OUP user menu

Management of acute myocardial infarction in patients presenting with ST-segment elevation

Frans Van de Werf, Diego Ardissino, Amadeo Betriu, Dennis V. Cokkinos, Erling Falk, Keith A.A. Fox, Desmond Julian, Maria Lengyel, Franz-Josef Neumann, Witold Ruzyllo, Christian Thygesen, S. Richard Underwood, Alec Vahanian, Freek W.A. Verheugt, William Wijns
DOI: http://dx.doi.org/10.1016/S0195-668X(02)00618-8 28-66 First published online: 1 January 2003
  • Acute myocardial infarction
  • drug therapy
  • ischaemic heart disease

  • Introduction

  •     The definition of acute myocardial infarction

  •     The pathogenesis of acute myocardialinfarction

  •     The natural history of acute myocardial infarction

  •     Aims of management

  • Emergency care

  •     Initial diagnosis and early risk stratification

  •     Relief of pain, breathlessness and anxiety

  •     Cardiac arrest

  •     Basic life support

  •     Advanced life support

  • Pre-hospital or early in-hospital care

  •     Restoring coronary flow and myocardial tissue reperfusion

  •     Fibrinolytic treatment

  •     Fibrinolytic regimens

  •     Percutaneous coronary interventions (PCI)

  •     Primary PCI

  •     PCI combined with fibrinolysis

  •     ‘Rescue’ PCI

  •     Assessing myocardial salvage by fibrinolysis or PCI

  •     GP IIb/IIIa antagonists and early PCI

  •     Coronary artery bypass surgery

  •     Pump failure and shock

  •     Heart failure

  •     Mild and moderately severe heart failure

  •     Severe heart failure and shock

  •     Mechanical complications: cardiac rupture and mitral regurgitation

  •     Free wall rupture

  •     Ventricular septal rupture

  •     Mitral regurgitation

  •     Arrhythmias and conduction disturbances

  •     Ventricular arrhythmias

  •     Supraventricular arrhythmias

  •     Sinus bradycardia and heart block

  •     Routine prophylactic therapies in the acute phase

  •     Management of specific types of infarction

  •     Right ventricular infarction

  •     Myocardial infarction in diabetic patients

  • Management of the later in-hospital course

  •     Ambulation

  •     Management of specific in-hospital complications

  •     Deep vein thrombosis and pulmonary embolism

  •     Intraventricular thrombus and systemic emboli

  •     Pericarditis

  •     Late ventricular arrhythmias

  •     Post-infarction angina and ischaemia

  • Risk assessment, rehabilitation and secondary prevention

  •     Risk assessment

  •     Timing

  •     Clinical assessment and further investigations

  •     Assessment of myocardial viability, stunning and hibernation

  •     Evaluation of risk of arrhythmia

  •     Rehabilitation

  •     Secondary prevention

  • Logistics of care

  •     Pre-hospital care

  •     The coronary (cardiac) care unit (CCU)

  • The current use of therapies tested by clinical trials

  • Recommendations

  • References


The management of acute myocardial infarction continues to undergo major changes. Good practice should be based on sound evidence derived from well-conducted clinical trials. Because of the great number of trials on new treatments performed in recent years and because of new diagnostic tests, the European Society of Cardiology decided that it was opportune to upgrade the 1996 guidelines and appointed a Task Force. It must be recognized, that even when excellent clinical trials have been undertaken, their results are open to interpretation and that treatment options may be limited by resources. Indeed, cost-effectiveness is becoming an increasingly important issue when deciding upon therapeutic strategies.

In setting out these new guidelines, the Task Force has attempted to classify the usefulness or efficacy of the recommended routine treatments and the level of evidence on which these recommendations are based. The usefulness or efficacy of a recommended treatment will be presented as:

  • class I=evidence and/or general agreement that a given treatment is beneficial, useful and effective;

  • class II=conflicting evidence and/or a divergence of opinion about the usefulness/efficacy of the treatment;

  • IIa: weight of evidence/opinion is in favour of usefulness/efficacy;

  • IIb: usefulness/efficacy is less well established by evidence/opinion;

  • class III=evidence or general agreement that the treatment is not useful/effective and in some cases may be harmful.

The strength of evidence will be ranked according to three levels: level A, data derived from at least two randomized clinical trials; level B, data derived from a single randomized clinical trial and/or meta-analysis or from non-randomized studies; level C, consensus opinion of the experts based on trialsand clinical experience. As always with guidelines, they are not prescriptive. Patients vary so much from one another that individual care is paramount and there is still an important place for clinical judgment, experience and common sense.

The definition of acute myocardial infarction

Myocardial infarction can be defined from a number of different perspectives related to clinical, electrocardiographic (ECG), biochemical and pathologic characteristics.1 It is accepted that the term myocardial infarction reflects death of cardiac myocytes caused by prolonged ischaemia.

The ECG may show signs of myocardial ischaemia, specifically ST and T changes, as well as signs of myocardial necrosis, specifically changes in the QRS pattern. A working definition for acute evolving myocardial infarction in the presence of clinically appropriate symptoms has been established as (1) patients with ST-segment elevation, i.e. new ST-segment elevation at the J point with the cut-off points ≥0.2mV in V1through V3and ≥0.1mV in other leads, or (2) patients without ST-segment elevation, i.e. ST-segment depression or T wave abnormalities. Clinically established myocardial infarction may be defined by any Q wave in leads V1through V3, or Q wave ≥0.03s in leads I, II, aVL, aVF, V4, V5or V6.

Myocardial infarction can be recognized when blood levels of biomarkers are increased in the clinical setting of acute myocardial ischaemia. The preferred biomarker for myocardial damage is cardiac troponin (I or T) which has nearly absolute myocardial tissue specificity, as well as high sensitivity. The best alternative is CK-MB mass, which is less tissue-specific than cardiac troponin but its clinical specificity for irreversible injury is more robust. An increased value of cardiac troponin or CK-MB is defined as one that exceeds the 99th percentile of a reference population.

The present guidelines pertain to patients presenting with ischaemic symptoms and persistent ST-segment elevation on the ECG. The great majority of these patients will show a typical rise of biomarkers of myocardial necrosis and progressto Q-wave myocardial infarction. Separate guidelines2 have been developed by another Task Force of the European Society of Cardiology for patients presenting with ischaemic symptoms but without persistent ST-segment elevation.

The pathogenesis of acute myocardial infarction

An acute coronary syndrome is nearly always caused by a sudden reduction in coronary blood flow caused by atherosclerosis with thrombosis superimposed, with or without concomitant vasoconstriction.3 The clinical presentation and outcome depend on the location of the obstruction and the severity and duration of myocardialischaemia. In myocardial infarction with ST-segment elevation, occlusive and persistent thrombosis prevails. About 2/3 to 3/4 of fatal coronary thrombi are precipitated by sudden rupture of a vulnerable plaque (inflamed, lipid-rich plaque covered by a thin fibrous cap).4 Other poorly defined mechanisms such as plaque erosion account for the rest. As many as 3/4 of all infarct-related thrombi appear to evolve over plaques causing only mild-to-moderate stenosis prior to infarction and after thrombolysis.4 However,severe stenoses are more likely to undergo plaque events leading to infarction than mild ones.5 Myocardial infarction caused by complete coronary artery occlusion begins to develop after 15–30min of severe ischaemia (no forward or collateral flow) and progresses from the subendocardium to the subepicardium in a time-dependent fashion (the wave-front phenomenon). Reperfusion, including recruitment of collaterals, may save myocardium at risk from undergoing necrosis, and subcritical but persistent flow may extend the time-window for achieving myocardial salvage by complete reperfusion.

The thrombotic response to plaque disruptionis dynamic: thrombosis and thrombolysis, oftenassociated with vasospasm, occur simultaneously, causing intermittent flow obstruction and distal embolization.3,6 The latter leads to microvascular obstruction which may prevent successful myocardial reperfusion despite a patent epicardial infarct-related artery.7 In coronary thrombosis, the initial flow obstruction is usually due to platelet aggregation, but fibrin is important for the subsequent stabilization of the early and fragile platelet thrombus.6 Therefore, both platelets and fibrin are involved in the evolution of a persisting coronary thrombus.

The natural history of acute myocardial infarction

The true natural history of myocardial infarction is hard to establish for a number of reasons: the common occurrence of silent infarction, the frequency of acute coronary death outside hospital and the varying methods used in the diagnosis of the condition. Community studies8,9 have consistently shown that the overall fatality of acute heart attacks in the first month is between 30% and 50%, and of these deaths about one-half occur within the first 2h. This high initial mortality seems to have altered little over the last 30 years.10 By contrast with community mortality, there has been a profound fall in the fatality of those treated in hospital. Prior to the introduction of coronary care units in the 1960s, the in-hospital mortality seems to have averaged some 25–30%.11 A systematic review of mortality studies in the pre-thrombolytic era of the mid-1980s showed an average fatality of 18%.12 With the widespread use of fibrinolytic drugs, aspirin and coronary interventions the overall 1-month mortality has since been reduced to 6–7%, at least in those who participate in large-scale trials and qualify for fibrinolysis, aspirin and/or coronary interventions. In the recent European Heart Survey, mortality in patients presenting with ST-segment elevation acute coronary syndromes was 8.4% at 1 month.13 The WHO-MONICA investigators convincingly demonstrated that, also at the population level, the introduction of new treatments for coronary care was strongly linked with declining coronary event rates and 28-day case fatality.9

It was found many years ago that certain factors were predictive of death in patients admitted to hospital with myocardial infarction.11 Chief among these were age, previous medical history (diabetes, previous infarction), indicators of large infarct size, including site of infarction (anterior vs inferior), low initial blood pressure, Killip class on admission and the extent of ischaemia as expressed by ST-segment elevation and/or depression on the electrocardiogram. These factors remain operative today.14

Aims of management

While the primary concern of physicians is to prevent death, those caring for victims of myocardial infarction aim to minimize the patient's discomfort and distress and to limit the extent of myocardial damage. The care can be divided conveniently into four phases:

  1. Emergency care when the main considerations are to make a rapid diagnosis and early risk stratification, to relieve pain and to prevent or treat cardiac arrest.

  2. Early care in which the chief considerations are to initiate as soon as possible reperfusion therapy to limit infarct size and to prevent infarct extension and expansion and to treat immediate complications such as pump failure, shock and life-threatening arrhythmias.

  3. Subsequent care in which the complications that usually ensue later are addressed.

  4. Risk assessment and measures to prevent progression of coronary artery disease, new infarction, heart failure and death.

These phases may correspond to pre-hospital care, the emergency department or the coronary care unit (CCU), the post CCU and an ordinary ward, but there is much overlap and any categorization of this kind is artificial.

Emergency care

Initial diagnosis and early risk stratification

Rapid diagnosis and early risk stratification ofpatients presenting with acute chest pain areimportant to identify patients in whom early interventions can improve outcome. On the other hand, when the diagnosis of acute myocardialinfarction has been ruled out, attention can be focused on the detection of other cardiac or non-cardiac causes of the presenting symptoms.

A working diagnosis of myocardial infarction must first be made. This is usually based on the history of severe chest pain lasting for 20min or more, not responding to nitroglycerine. Important clues are a previous history of coronary artery disease, and radiation of the pain to the neck, lower jaw, or left arm. The pain may not be severe and, in the elderly particularly, other presentations such as fatigue, dyspnoea, faintness or syncope are common. There are no individual physical signs diagnostic of myocardial infarction, but most patients have evidence of autonomic nervous system activation (pallor, sweating) and either hypotension or a narrow pulse pressure. Features may also include irregularities of the pulse, bradycardia or tachycardia, a third heart sound and basal rales.

An electrocardiogram should be obtained as soon as possible. Even at an early stage, the ECG is seldom normal.15,16 In case of ST-segment elevations or new or presumed new left bundle-branch block, reperfusion therapy needs to be given and measures to initiate this treatment must be taken as soon as possible. However, the ECG is often equivocal in the early hours and even in proven infarction it may never show the classical features of ST-segment elevation and new Q waves. Repeated ECG recordings should beobtained and, when possible, the current ECG should be compared with previous records. Additional recordings of e.g. lead V7and V8may be helpful to make the diagnosis in selected cases (true posterior infarction). ECG monitoring should be initiated as soon as possible in all patients to detect life-threatening arrhythmias.

Blood sampling for serum markers is routinely done in the acute phase but one should not wait for the results to initiate reperfusion treatment. The finding of elevated markers of necrosis may sometimes be helpful in deciding to give reperfusion therapy (e.g. in patients with left bundle-branch block).

Two-dimensional echocardiography has become a useful bedside technique in the triage of patients with acute chest pain. Regional wall motion abnormalities occur within seconds after coronary occlusion well before necrosis.17 However, wall motion abnormalities are not specific for acute myocardial infarction and may be due to ischaemia or an old infarction. Two-dimensional echocardiography is of particular value for the diagnosis of other causes of chest pain such as acute aortic dissection, pericardial effusion or massive pulmonary embolism.18 The absence of wall motion abnormalities excludes major myocardial infarction. In difficult cases, coronary angiography may be helpful.

Myocardial perfusion scintigraphy has also been used successfully, though unfrequently, in the triage of patients presenting with acute chest pain.19,20 A normal resting technetium-99m myocardial perfusion scintigram effectively excludes major myocardial infarction. An abnormal acute scintigram is not diagnostic of acute infarctionunless it is known previously to have been normal, but it does indicate the presence of coronary artery disease and the need for further evaluation.

When the history, ECG and serum markers are not diagnostic of acute myocardial infarction the patient can proceed safely to stress testing for investigation of underlying coronary artery disease.

Summary: initial diagnosis of acute myocardial infarction

  • History of chest pain/discomfort.

  • ST-segment elevations or (presumed) new left bundle-branch block on admission ECG. Repeated ECG recordings often needed.

  • Elevated markers of myocardial necrosis (CK-MB, troponins). One should not wait for the results to initiate reperfusion treatment!

  • 2D echocardiography and perfusion scintigraphy helpful to rule out acute myocardial infarction.

Relief of pain, breathlessness and anxiety

Relief of pain is of paramount importance, not only for humane reasons but because the pain is associated with sympathetic activation which causesvasoconstriction and increases the workload of the heart. Intravenous opioids—morphine or, where available, diamorphine—are the analgesics most commonly used in this context (e.g. 4 to 8mg morphine with additional doses of 2mg at intervals of 5min until the pain is relieved); intramuscular injections should be avoided. Repeated dosesmay be necessary. Side effects include nausea and vomiting, hypotension with bradycardia, andrespiratory depression. Antiemetics may be administered concurrently with opioids. The hypotension and bradycardia will usually respond to atropine, and respiratory depression to naloxone, which should always be available. If opioids fail to relieve the pain after repeated administration, intravenous beta-blockers or nitrates are sometimes effective. Oxygen (2–4l.min−1by mask or nasal prongs) should be administered especially to those who are breathless or who have any features of heart failure or shock. Non-invasive monitoring of blood oxygen saturation greatly helps in deciding on the need for oxygen administration or, in severe cases, ventilatory support.

Anxiety is a natural response to the pain andto the circumstances surrounding a heart attack. Reassurance of patients and those closely associated with them is of great importance. If thepatient becomes excessively disturbed, it maybe appropriate to administer a tranquilliser, but opioids are frequently all that is required.

Summary: relief of pain, breathlessness and anxiety.

  • Intravenous opioids (e.g. 4 to 8mg morphine) with additional doses of 2mg at 5min intervals.

  • O2(2–4l.min−1) if breathlessness or heart failure.

  • Consider intravenous beta-blockers or nitrates if opioids fail to relieve pain.

  • Tranquilliser may be helpful.

Cardiac arrest

Basic life support

Those not trained or equipped to undertake advanced life support should start basic life support as recommended in the international guidelines 2000 for resuscitation and emergency cardiovascular care.21

Advanced life support

Trained paramedics and other health professionals should undertake advanced life support, as described in the international guidelines for cardiopulmonary resuscitation and emergencycardiovascular care.22

Pre-hospital or early in-hospital care

Restoring coronary flow and myocardial tissue reperfusion

For patients with the clinical presentation of myocardial infarction and with persistent ST-segment elevation or new or presumed new left bundle-branch block, early mechanical or pharmacological reperfusion should be performed unless clearcontraindications are present.

Fibrinolytic treatment

The evidence for benefit

More than 150 000 patients have been randomized in trials of thrombolysis vs control, or one fibrinolytic regimen compared with another.23–35 Forpatients within 12h of the onset of symptoms of infarction, the overall evidence for the benefit of fibrinolytic treatment is overwhelming.

According to the Fibrinolytic Therapy Trialists' (FTT) analysis for those presenting within 6h of symptom onset, arid ST-segment elevation or bundle-branch block, approximately 30 deaths are prevented per 1000 patients treated, with 20 deaths prevented per 1000 patients treated for those between 7 and 12h. Beyond 12h there is no convincing evidence of benefit for the group as a whole.23 The amount of ST-segment elevationrequired and the type of bundle-branch block were not specified in this meta-analysis. However, most of the trials included in the analysis used ST-segment elevations of ≥1mm or new or presumed new left bundle-branch block as entry criteria.

The ISIS-224 study demonstrated the important additional benefit of aspirin so that there was a combined reduction of approximately 50 lives per 1000 patients treated. There is remarkable consistency of benefit across pre-stratified subgroups. Overall, the largest absolute benefit is seen among patients with the highest risk, even though the proportional benefit may be similar.

In patients over 75 and treated within 24h the survival benefit shown in the FTT analysis was small and not statistically significant.22 Two recent registry-type studies36,37 questioned the benefit of fibrinolytic therapy in the elderly, with one of these studies even suggesting more harm than good.36 However, a recent re-analysis by the FTT secretariat indicates that in approximately 3300 patients over the age of 75 presenting within 12h of symptom onset and with either ST-segment elevation or bundle-branch block, mortality rates were significantly reduced by fibrinolytic therapy (from 29.4% to 26%, P=0.03).38

Time to treatment

Most benefit is seen in those treated soonest after the onset of symptoms. Analysis of studies in which more than 6000 patients were randomized to pre-hospital or in-hospital thrombolysis has shown significant reduction (range 15 to 20%) in early mortality with pre-hospital treatment.39–41 Thefibrinolytic overview23 reported a progressivedecrease of about 1.6 deaths per hour of delay per 1000 patients treated. In another meta-analysis of 22 trials42 a larger mortality reduction was found in patients treated within the first 2h (44% vs 20% for those treated later). These calculations, based on studies in which the time to treatment was not randomized, must be interpreted with cautionbecause the time to presentation is not random. Nevertheless they should be considered as an additional indirect support for pre-hospital initiation of fibrinolytic treatment. The availability of new fibrinolytic agents that can be given as a bolus (cfr. infra) should facilitate pre-hospital thrombolysis.

Hazards of fibrinolysis

Thrombolytic therapy is associated with a small but significant excess of approximately 3.9 extra strokes per 1000 patients treated23 with all ofthe excess hazard appearing on the first dayafter treatment. The early strokes are largelyattributable to cerebral haemorrhage; later strokes are more frequently thrombotic or embolic. There is a non-significant trend for fewer thrombo-embolic strokes in the later period in those treated with fibrinolysis: Part of the overall excess of stroke is among patients who subsequently die and is accounted for in the overall mortality reduction (1.9 excess per 1000). Thus, there is an excess of approximately two non-fatal strokes per 1000 surviving patients treated. Of these, half are moderately or severely disabling. Advanced age, lower weight, female gender, prior cerebrovascular disease or hypertension, systolic and diastolic hypertension on admission are significant predictors of intracranial haemorrhage.43–45 Major non-cerebral bleeds (bleeding complications requiring blood transfusion or that are life-threatening), can occur in 4% to 13% of the patients treated.33,46 The most common sources of bleeding are procedure-related. Independent predictors of non-cerebral bleeding are older age, lower weight and female gender, also in patients not undergoing percutaneous interventions.

Administration of streptokinase and anistreplase may be associated with hypotension, but severe allergic reactions are rare. Routine administration of hydrocortisone is not indicated. Where hypotension occurs, it should be managed bytemporarily halting the infusion, lying thepatient flat or elevating the feet. Occasionally atropine or intravascular volume expansion may be required.

Comparison of fibrinolytic agents

Neither the GISSI-2/International Trials27 nor the Third International Study of Infarct Survival(ISIS 3)25 found a difference in mortality between the use of streptokinase and tissue plasminogen activator or anistreplase. Furthermore, the addition of subcutaneous heparin did not reduce mortality compared with the use of no heparin. However, the GUSTO Trial (Global Utilisation of Streptokinase and Tissue Plasminogen Activator for occluded coronary arteries)28 employed an accelerated t-PA (tissue type plasminogen activator) regimen given over 90min29 rather than the previously conventional period of 3h. Accelerated t-PA with concomitant APTT (activated partial thromboplastin time) adjusted intravenous heparin was reported to result in 10 fewer deaths per 1000 patients treated. The risk of stroke is higher with t-PA or anistreplase than with streptokinase.24,28 In the GUSTO trial, there were three additional strokes per 1000 patients treated with accelerated t-PA and heparin in comparison with streptokinase and subcutaneous heparin,28 but only one of these survived with a residual deficit. In assessing the net clinical benefit, this must be taken into account with the reduced death rate in the t-PA group. Several variants of t-PA have been studied. Double-bolus r-PA (reteplase) does not offer any advantage over accelerated t-PA except for its ease of administration. Single-bolus weight-adjusted TNK-tPA (tenecteplase) is equivalent to accelerated t-PA for 30-day mortality and associated with a significantly lower rate of non-cerebral bleeds and less need for blood transfusion. Bolus fibrinolytic therapy may facilitate more rapid treatment in and out of the hospital and reduce the risk of medication errors. The choice of fibrinolytic agent will depend on an individual assessment of risk and benefit, and also on factors such as availability and cost.45 For late treated patients more fibrin-specific agents may be more effective.30,33,48

Clinical implications

Based upon the substantial evidence now accumulated, there is unequivocal benefit, in terms of morbidity and mortality for prompt treatment of acute myocardial infarction with fibrinolytic agents and aspirin, the two agents being additive in their effect. Where appropriate facilities exist, with trained medical or paramedical staff able to analyse on-site or to transmit the ECG to the hospital for supervision, pre-hospital fibrinolysis is recommended provided that the patient exhibits the clinical features of myocardial infarction andthe ECG shows ST-segment elevation or new or presumed new left bundle-branch block.

Unless clearly contraindicated, patients withinfarction, as diagnosed by clinical symptoms and ST-segment elevation or left bundle-branch block, should receive aspirin and fibrinolytic therapy with the minimum of delay. A realistic aim is to initiate fibrinolysis within 90min of the patient calling for medical treatment (‘call to needle’ time) or within 30min of arrival at the hospital (‘door to needle’ time). In patients withslowly evolving, or stuttering myocardial infarction, a series of ECGs or ST-segment monitoring, clinical assessments and repeat testing of serum markers should be performed to detect evolving infarction.

Fibrinolytic therapy should not be given topatients in whom infarction has been established for more than 12h, unless there is evidence of ongoing ischaemia, with the ECG criteria forfibrinolysis. Elderly patients without contraindications should be given fibrinolytic therapy when timely mechanical reperfusion can not be performed.

Contra-indications to fibrinolytic therapy

Absolute and relative contraindications to fibrinolytic therapy are shown in Table 1. It should be stressed that diabetes, and more particularly diabetic retinopathy, is not a contraindication tofibrinolytic therapy. Although traumatic resuscitation is considered to represent a relativecontraindication to thrombolysis, out-of-hospitalthrombolytic therapy may improve outcome ofpatients in whom initial conventional cardiopulmonary resuscitation was unsuccessful.49

View this table:
Table 1

Contraindications to fibrinolytic therapy

Absolute contraindications
Haemorrhagic stroke or stroke of unknown origin at any time
Ischaemic stroke in preceding 6 months
Central nervous system damage or neoplasms
Recent major trauma/surgery/head injury (within preceding 3 weeks)
Gastro-intestinal bleeding within the last month
Known bleeding disorder
Aortic dissection
Relative contraindications
Transient ischaemic attack in preceding 6 months
Oral anticoagulant therapy
Pregnancy or within 1 week post partum
Non-compressible punctures
Traumatic resuscitation
Refractory hypertension (systolic blood pressure >180mmHg)
Advanced liver disease
Infective endocarditis
Active peptic ulcer

Fibrinolytic regimens

Dosages for the current fibrinolytic agents and the need for antithrombin co-therapy are provided in Table 2.

View this table:
Table 2

Fibrinolytic regimens for acute myocardial infarction

Initial treatmentAntithrombin co-therapySpecific contraindications
Streptokinase (SK)1.5 million units in 100ml of 5%dextrose or 0.9% saline over 30–60minNone or i.v. heparin for 24 to 48hPrior SK or anistreplase
Alteplase (tPA)15mg i.v. bolusi.v. heparin for 24 to 48h
0.75mg.kg−1over 30min then
0.5mg.kg−1over 60min i.v.
Total dosage not to exceed 100mg
Reteplase (r-PA)10 U+10 U i.v. bolus given 30min aparti.v. heparin for 24 to 48h
Tenecteplase (TNK-tPA)single i.v. bolusi.v. heparin for 24 to 48h
30mg if <60kg
35mg if 60 to <70kg
40mg if 70 to <80kg
45mg if 80 to <90kg
50mg if ≥90kg
  • This table describes frequently used fibrinolytic regimens.

    N.B. Aspirin should be given to all patients without contraindications.

Re-administration of a fibrinolytic agent

If there is evidence of re-occlusion or reinfarction with recurrence of ST-segment elevation or bundle-branch block, further fibrinolytic therapy shouldbe given if mechanical reperfusion is not available.50 Streptokinase and anistreplase should not be re-administered since antibodies to streptokinase persist for at least 10 years, at levels which can impair its activity.51 Alteplase (t-PA) and its variants do not result in antibody formation.Re-administration of fibrinolytic agents may lead to excessive bleeding complications.

Adjunctive anticoagulant and antiplatelet therapy

The independent and additive benefits of aspirin have been described above. It is not clear whether aspirin works by enhancing fibrinolysis, preventing reocclusion or by limiting the microvascular effects of platelet activation. In studies on late reocclusion, aspirin was more effective in preventingrecurrent clinical events than in maintainingpatency.52 The first dose of 150–325mg should be chewed (no enteric-coated aspirin!), and a lower dose (75–160mg) given orally daily thereafter. If oral ingestion is not possible aspirin can be given intravenously (250mg).

Platelet aggregation is only partly inhibited by aspirin and progress has been made with the development of platelet glycoprotein IIb/IIIa inhibitors, which block the final pathway of platelet aggregation. Angiographic trials53–57 demonstrated that the combination of GP IIb/IIIa inhibitors with half-dose fibrinolytic and reduced doses of heparin, induces similar or slightly higher TIMI grade 3 flow rates when compared with full-dose fibrinolytic alone and is associated with more complete resolutionof ST-segment elevations, suggesting an improvement in tissue reperfusion. The clinical benefit and safety of these combinations has been tested in two large trials.58,59 No reductions in 30-day mortality or intracranial haemorrhage rates but lower rates of in-hospital reinfarction were observed, however, at the cost of an increase in (mostly spontaneous) non-cerebral bleeding complications especially in elderly patients. Therefore, the routine use of a reduced dose fibrinolytic with abciximab or other platelet glyco-protein IIb/IIIa inhibitors cannotbe recommended. Whether this combination therapy may be beneficial in specific subgroups of patients (for example those at high risk or those likely to undergo early PCI) needs to be further evaluated.

Heparin has been extensively used during and after fibrinolysis, especially with tissue plasminogen activator. Heparin does not improve immediate clot lysis60 but coronary patency evaluated in the hours or days following thrombolytic therapywith tissue plasminogen activator appears to be better with intravenous heparin.61,62 No difference in patency was apparent in patients treated with either subcutaneous or intravenous heparin and streptokinase.63 Prolonged intravenous heparin administration has not been shown to prevent reocclusion after angiographically proven successful coronary fibrinolysis.64 Heparin infusion after tissue plasminogen activator therapy may be discontinued after 24–48h. Close monitoring of intravenous heparin therapy is mandatory; aPTT values over 70s are associated with higher likelihood of mortality, bleeding and reinfarction.65 Although no randomized trials have beenperformed, there is evidence from recent trials suggesting that more frequent monitoring ofaPTT and a full weight adjustment of heparinmay decrease the risk of non-cerebral bleeding complications.59,66

Low-molecular-weight heparin is a subfraction of standard heparin. It has a number of theoretical advantages over standard heparin: better prevention of new thrombin generation due to its greater degree of factor-Xa inhibition, more predictable kinetics, less protein-binding, less platelet activation, a lower rate of thrombocytopenia and the lack of a need to monitor the aPTT. Low-molecular-weight heparins have been studied in large numbers of patients with non-ST-segment elevation acute coronary syndromes but only recently has testing begun in combination with fibrinolytic agents. Two earlier clinical studies suggest that dalteparin compared with heparin may reduce the risks of recurrent ischaemia67 and of ventricular thrombus formation, albeit at the expense of a higher rate of bleeding.68 In three more recent angiographicstudies69–71 enoxaparin or dalteparin were associated with a trend towards less reocclusion and/or more late patency of the infarct vessel. In the ASSENT-3 trial, the first large-scale trial with a low-molecular-weight heparin, enoxaparin (30mg i.v. bolus and 1mg.kg−1every 12h) given in association with tenecteplase for a maximum of7 days59 reduced the risk of in-hospital reinfarction or in-hospital refractory ischaemia when compared with heparin. There was no increase in intracranial haemorrhage rate and only a modest increase in non-cerebral bleeding complications when compared with heparin. Mortality at 30 days also tended to be lower with enoxaparin. However, in the ASSENT-3 PLUS trial71a prehospital administration of the same dose of enoxaparin resulted in a significant increase in intracranial haemorrhage rate when compared with heparin. This excess was only seen in patients ≥75 years. Larger studies (especially in the elderly) are needed beforerecommendations can be given on the use of enoxaparin or other low-molecular-weight heparins in combination with fibrinolytic agents.

In early studies, the direct thrombin inhibitors, hirudin, bivalirudin and argatroban, as an adjunct to fibrinolysis showed superior patencies at adecreased rate of bleeding compared with heparin.72–74 Nevertheless, in two large-scale clinical trials, hirudin showed no clear clinical benefit over heparin in patients given fibrinolytic therapy.75,76 A multicentre trial with bivalirudin in combination with streptokinase has recently been published.77 When compared with intravenous heparin no mortality reduction at 30 days but significantly fewer reinfarctions were seen with intravenous bivalirudin given for 48h at the cost of a modest and non-significant increase in non-cerebral bleeding complications. Bivalirudin is not approved in Europe. Recommended doses for heparin are given in Table 3.

View this table:
Table 3

Heparin co-therapy

Heparini.v. bolus: 60U.kg−1with a maximum of 4000U
i.v. infusion: 12U.kg−1for 24 to 48h with a maximum of 1000U.h−1target aPTT: 50–70ms
aPTT to be monitored at 3, 6, 12, 24h after start of treatment

Percutaneous coronary interventions (PCI)

The role of percutaneous coronary interventions (PCI) during the early hours of myocardial infarction can be divided into primary PCI, PCI combined with pharmacological reperfusion therapy, and ‘rescue PCI’ after failed pharmacological reperfusion.

Primary PCI

This is defined as angioplasty and/or stenting without prior or concomitant fibrinolytic therapy, and is the preferred therapeutic option when it can be performed within 90min after the first medical contact. It requires an experienced team, which includes not only interventional cardiologists, but also skilled supporting staff. This means that only hospitals with an established interventional cardiology programme should use primary PCI as a routine treatment option for patients presenting with the symptoms and signs of acute myocardial infarction. Lower mortality rates among patients undergoing primary PCI are observed in centres with a high volume of PCI procedures.78 For patients admitted to a hospital without catheterization facilities on site, a careful individual assessment should be made of thepotential benefits of mechanical reperfusion in relation to the risks and treatment delay of transportation to the nearest interventional catheterization laboratory. Recently the DANAMI-2 investigators have investigated whether a strategy of routine transfer to a tertiary care hospital for primary PCI is superior to in-hospital thrombolysis.79 Transfer times up to 3h from admission at community hospitals to arrival at the invasive centre were allowed per protocol. The observedmedian transport time by ambulance was <32min and the median time between arrival at the community hospital and start of PCI was <2h. A significant reduction in the combined end-point of death, reinfarction and stroke was found after 30 days in the transferred patients undergoing primary PCI (14.2% to 8.5%, P<0.002), while mortality reduction was not significant (8.6% vs 6.5%, P=0.20). In the CAPTIM study comparing pre-hospital (ambulance) fibrinolysis with primaryPCI, no significant difference was found for this combined end-point (8.2% vs 6.2%) and 30-day mortality was 1% higher in the primary PCI arm (3.8% vs 4.8%).80

Primary PCI is effective in securing and maintaining coronary artery patency and avoids some of the bleeding risks of fibrinolysis. Randomized clinical trials comparing timely performed primary PCI with fibrinolytic therapy in high-volume, experienced centres have shown more effective restorationof patency, less reocclusion, improved residualleft ventricular function and better clinical outcome.81–87 Routine coronary stent implantation in patients with acute myocardial infarction decreases the need for target-vessel revascularization but is not associated with significant reductions in death or reinfarction rates88,89 when compared with primary angioplasty.

Patients with contra-indications to fibrinolytic therapy have a higher morbidity and mortality than those eligible for this therapy.90 Primary PCI can be performed with success in a large majority of these patients.91 Primary PCI is the preferred treatment for patients in shock.

PCI combined with fibrinolysis

PCI performed as a matter of policy immediately after fibrinolytic therapy, in order to enhance reperfusion or reduce the risk of reocclusion, has proved disappointing in a number of earlier trialsall showing a tendency to an increased risk of complications and death.92–94 Increased experience and the availability of stents and more potent antiplatelet agents (glycoprotein IIb/IIIa receptor antagonists and thienopyridines) have made PCI following fibrinolysis effective and safe. A combined pre-hospital pharmacological and mechanical reperfusion strategy might prove to be beneficial95 and is currently under investigation.

‘Rescue PCI’

‘Rescue PCI’ is defined as PCI performed on a coronary artery which remains occluded despite fibrinolytic therapy. Limited experience from two randomized trials96,97 suggests a trend towards clinical benefit if the infarct-related vessel canbe recanalized at angioplasty. Although angioplasty success rates are high, an unsolved problem is the lack of reliable non-invasive methods for assessing patency of the infarct-relatedcoronary artery. Limited data from a number of studies indicate that transfer to a tertiary care hospital for rescue PCI can be performed safely.98 Coronary intervention in patients who received full-dose fibrinolytics and a glycoprotein IIb/IIIa antagonist may lead to excessive bleeding complications.

Assessing myocardial salvage by fibrinolysis or PCI

Although not commonly used in clinical practice, myocardial perfusion scintigraphy can be a valuable research technique for assessing the amount of myocardium salvaged by fibrinolysis or PCI. A technetium-99m perfusion tracer can be given intravenously before the intervention and imaging of the territory at risk is possible for up to 6h. Repeat injection and imaging in the recovery phase defines the final size of infarction and the amount of myocardium salvaged by comparison with the territory at risk.85,99

GP IIb/IIIa antagonists and early PCI

Randomized trials with abciximab as conjunctive antiplatelet therapy during PCI of the infarct-related coronary artery have been performed in recent years.89,100–102

The RAPPORT study102 showed that abciximab improves the immediate clinical outcome (death, myocardial infarction, and urgent revascularization) and decreases the need for ‘bail-out’ stenting. Haemorrhagic complications, however, were significantly increased in the abciximab group, likely as a result of relatively high heparin doses. In addition, the combined primary end-point of death, reinfarction, and any revascularization was not significantly improved by abciximab at 6 months. The role of abciximab during primary PCI has been further investigated in the ISAR-2, CADILLAC and ADMIRAL trials. In the ISAR-2 study101 the administration of abciximab and reduced-dose heparin during primary stenting was associated with a significant reduction in the composite of death, reinfarction and target lesion revascularization at 30 days but did not reduce angiographic restenosis rate. In the ADMIRAL study abciximab, given before catheterization, improved angiographic and clinical outcomes after primary stenting.100 In the largest study, the CADILLAC trial, a favourable effect of abciximab was only observed when abciximab was given duringprimary angioplasty but not during primary stenting.89

Thus the current data support the use of abciximab in primary angioplasty in combination with low-dose heparin. The routine administration of abciximab with primary stenting is still a matter of debate.

Coronary artery bypass surgery

The number of patients who need coronary artery bypass surgery in the acute phase of myocardial infarction is limited. It may, however, be indicated when PCI has failed, when there has been a sudden occlusion of a coronary artery during catheterization, if PCI is not feasible, in selected patients in cardiogenic shock or in association with surgeryfor a ventricular septal defect or mitral regurgitation due to papillary muscle dysfunction and rupture.

Reperfusion therapy
RecommendationsClass IIIaIIbIIILevel of evidence
Reperfusion therapy is indicated in all patients with history of chest pain/discomfort of <12h and associated with ST-segment elevation or (presumed) new bundle-branch block on the ECGXA
Primary PCI
•preferred treatment if performed by experienced team <90min after first medical contactXA
•indicated for patients in shock and those with contraindications to fibrinolytic therapyXC
•GP Ilb/IIIa antagonists and primary PCI
no stentingXA
with stentingXA
Rescue PCI
•after failed thrombolysis in patients with large infarctsXB
Fibrinolytic treatment
In the absence of contraindications (see Table 1) and if primary PCI cannot be performed within 90min after first medical contact by an experienced team pharmacological reperfusion should be initiated as soon as possibleXA
•choice of fibrinolytic agent depends on individual assessment of benefit and risk, availability and cost
In patients presenting late (>4h after symptom onset) a more fibrin-specific agent such as tenecteplase or alteplase is preferredXB
For dosages of fibrinolytic and antithrombin agents see Tables 2 and 3
•pre-hospital initiation of fibrinolytic therapy if appropriate facilities existXB
•readministration of a non-immunogenic lytic agent if evidence of reocclusion and mechanical reperfusion not availableXB
•if not already on aspirin 150–325mg chewable aspirin (no enteric-coated tablets)XA
•with alteplase and reteplase a weight-adjusted dose of heparin should be given with early and frequent adjustments according to the aPTTXB
•with streptokinase heparin is optional X B

Pump failure and shock

The various haemodynamic states that can arise in myocardial infarction are tabulated in Table 4.In addition, heart failure may arise from arrhythmic or mechanical complications (see respective sections).

View this table:
Table 4

Clinical spectrum of haemodynamic states in myocardial infarction and their treatment

Normal:normal blood pressure, heart and respiration rates, good peripheral circulation.
Hyperdynamic state:tachycardia, loud heart sounds, good peripheral circulation. Beta-blocker therapy indicated.
Bradycardia-hypotension:‘warm hypotension’, bradycardia, venodilatation, normal jugular venous pressure, decreased tissue perfusion. Usually in inferior infarction, but may be provoked by opiates. Responds to atropine or pacing.
Hypovolaemia:venoconstriction, low jugular venous pressure, poor tissue perfusion. Responds to fluid infusion.
Right ventricular infarction:high jugular venous pressure, poor tissue perfusion or shock, bradycardia, hypotension. See text.
Pump failure:tachycardia, tachypnoea, small pulse pressure, poor tissue perfusion, hypoxaemia, pulmonary oedema. See text.
Cardiogenic shock:very poor tissue perfusion, oliguria, severe hypotension, small pulse pressure, tachycardia, pulmonary oedema. See text.

Heart failure

Left ventricular failure during the acute phase of myocardial infarction is associated with a poor short and long-term prognosis.103 The clinical features are those of breathlessness, sinus tachycardia, a third heart sound and pulmonary rales which are at first basal but may extend throughout both lung fields. However, pronounced pulmonary congestion can be present without auscultatory signs. Repeated auscultation of the heart and lung fields should be practised in all patients during the early period of myocardial infarction, together with the observation of other vital signs.

General measures include monitoring for arrhythmias, checking for electrolyte abnormalities, and for the diagnosis of concomitant conditions such as valvular dysfunction or pulmonary disease. Pulmonary congestion can be assessed by portable chest X-rays. Echocardiography is very useful in assessing the extent of myocardial damage, mechanical ventricular function and complications, such as mitral regurgitation and ventricular septal defect, which may be responsible for poor cardiac performance. In patients with severe heart failure or shock percutaneous or surgical revascularization can improve survival.

The degree of failure may be categorized according to the Killip classification:104 class 1: no rales or third heart sound; class 2: rales over less than 50% of the lung fields or third heart sound; class 3: rales over 50% of the lung fields; class 4: shock.

Mild and moderately severe heart failure

Oxygen should be administered early by mask or intranasally, but caution is necessary in the presence of chronic pulmonary disease. Monitoring blood oxygen saturation is recommended.

Minor degrees of failure often respond quicklyto diuretics, such as furosemide 20–40mg given slowly intravenously, repeated at 1–4 hourlyintervals, if necessary. If there is no satisfactoryresponse, intravenous nitroglycerine or oralnitrates are indicated. The dose should be titrated while monitoring blood pressure to avoid hypotension. ACE inhibitors should be initiated within 48h in the absence of hypotension, hypovolaemia or significant renal failure.

Severe heart failure and shock

Oxygen should be administered and a loop diuretic given as mentioned above. Unless the patient is hypotensive, intravenous nitroglycerine should be given, starting with 0.25μg.kg−1min−1, and increasing every 5min until a fall in blood pressure by 15mmHg is observed or the systolic blood pressure falls to 90mmHg. Consideration should be given to measuring the pulmonary artery and wedge pressures, and the cardiac output with a balloon flotation catheter with a view to obtaining a wedge pressure of less than 20mmHg and a cardiac index in excess of 2l.min−1.m−2.

Inotropic agents may be of value if there is hypotension. If signs of renal hypoperfusion are present, dopamine is recommended intravenously in a dosage of 2.5–5.0μg.kg−1min−1. If pulmonary congestion is dominant, dobutamine is preferred with an initial dosage of 2.5μg.kg−1min−1. This may be increased gradually at 5–10min intervalsup to 10μg.kg−1min−1or until haemodynamicimprovement is achieved.

The blood gases should be checked. Endotracheal intubation with ventilatory support may be indicated if an oxygen tension of more than 60mmHg cannot be maintained in spite of 100% oxygen delivered at 8–10l.min−1by mask and the adequate use of bronchodilators. Patients with acute heart failure may have stunned (reperfused myocardium but with delayed contractile recovery) or hypoperfused, viable myocardium. Identification and revascularization of hypoperfused myocardium can lead to improved ventricular function.

Cardiogenic shock

Cardiogenic shock is a clinical state of hypoperfusion characterized by systolic pressure <90mmHg and central filling pressure >20mmHg, or a cardiac index <1.8l.min−1.m−2. Shock is also considered present if intravenous inotropes and/or intraaortic balloon pump are needed to maintain a systolic blood pressure >90mmHg and a cardiac index of >1.8l.min−1.m−2. Early thrombolysis reduces the incidence of cardiogenic shock.

The diagnosis of cardiogenic shock should be made when other causes of hypotension have been excluded such as hypovolaemia, vasovagal reactions, electrolyte disturbance, pharmacological side effects, or arrhythmias. It is usually associated with extensive left ventricular damage, but may occur in right ventricular infarction (vide infra). Left ventricular function and associated mechanical complications should be evaluated by two-dimensional Doppler echocardiography. Haemodynamic assessment is usually performed with a balloon floating catheter. A filling pressure (pulmonary wedge) of at least 15mmHg should be aimed for with a cardiac index of >2l.kg−1min−1. Low-dose dopamine 2.5–5μg.kg−1min−1may be given to improve renal function and the additional administration of dobutamine 5–10μg.kg−1min−1should be considered.

Patients in cardiogenic shock can be assumed to be acidotic. Correction of acidosis is important as catecholamines have little effect in an acidmedium. Supportive treatment with a balloon pump is strongly recommended as a bridge tomechanical interventions.

Emergency PCI or surgery may be life-saving and should be considered at an early stage.105,106 If neither of these are available or can only be provided after a long delay, fibrinolytic therapy should be given.

Summary: pump failure and shock.

  • Diagnosis: chest X-ray, echocardiography, right heart catheterization.

  • Treatment of mild and moderately severe heart failure:


    furosemide: 20–40mg intravenously repeated at 1–4 hourly intervals if necessary

    nitrates: if no hypotension

    ACE inhibitors in the absence of hypotension, hypovolaemia or renal failure.

  • Treatment of severe heart failure:


    furosemide: cfr. supra

    nitrates if no hypotension

    inotropic agents: dopamine and/or dobutamine

    haemodynamic assessment with balloon floating catheter

    ventilatory support if inadequate oxygen tension

    consider early revascularization.

  • Treatment of shock:


    haemodynamic assessment with balloon floating catheter

    inotropic agents: dopamine and dobutamine

    ventilatory support if inadequate oxygen tension

    intraaortic balloon pump

    consider left ventricular assist devices and early revascularization.

Mechanical complications: cardiac rupture and mitral regurgitation

Free wall rupture

Acute free wall rupture

This is characterized by cardiovascular collapse with electromechanical dissociation i.e. continuing electrical activity with a loss of cardiac output and pulse. It is usually fatal within a few minutes, and does not respond to standard cardiopulmonaryresuscitation measures. Only very rarely is there time to bring the patient to surgery.

Subacute free wall rupture

In about 25% of cases, small quantities of blood reach the pericardial cavity and produce a progressive haemodynamic burden.107,108 The clinical picture may simulate reinfarction because of the recurrence of pain and re-elevation of ST segments, but more frequently there is sudden haemodynamic deterioration with transient or sustained hypotension. The classical signs of cardiac tamponade occur and can be confirmed by echocardiography. Although echocardiography is usually not able to show the site of rupture, it can demonstrate pericardial fluid with or without signs of tamponade. The presence of pericardial fluid alone is not sufficient to diagnose a subacute free wall rupture, because it is relatively common after acute myocardial infarction. The typical finding is an echo-dense mass in the pericardial space consistent with clot (haemopericardium). Immediate surgery should be considered depending on the clinical status. Pericardiocentesis may relieve tamponade in shock patients awaiting surgery.109

Ventricular septal rupture

Ventricular septal defect appears early after myocardial infarction, with an incidence of about 1–2% of all infarctions.110 Without surgery, the mortality is 54% within the first week, and 92% within the first year.111 The diagnosis, first suspected because of severe clinical deterioration, is confirmed by the occurrence of a loud systolic murmur, by echocardiography and/or by detecting an oxygen step-up in the right ventricle. Themurmur may, however, be soft or absent. Echocardiography reveals the location and size of the ventricular septal defect, the left-to-right shunt can be depicted by colour Doppler and further quantified by pulsed Doppler technique. Peak flow velocity across the rupture measured by continuous-wave Doppler can be used to estimate right ventricular (pulmonary) systolic pressure. Pharmacological treatment with vasodilators, such as intravenous nitroglycerine, may produce some improvement if there is no cardiogenic shock, but intra-aortic balloon counterpulsation is the most effective method of providing circulatory support while preparing for surgery. Urgent surgery offers the only chance of survival in large post-infarction ventricular septal defect with cardiogenic shock.112,113 Even if there is no haemodynamic instability early surgery is usually indicated, also because the defect may increase.114 Successful percutaneous closure of the ventricular septal defect has been reported but more experience is needed before it can be recommended.

Pre-operative coronary angiography should be performed. Bypass grafts are inserted as necessary. Predictors of poor postoperative outcome are cardiogenic shock, posterior location, right ventricular dysfunction, age, and long delay between septal rupture and surgery.111,112 Hospital mortality after surgery is estimated to be between 25% and 60%,114,115 and 95% of survivors are in NYHA class I or II.115

Mitral regurgitation

Mitral regurgitation is common after acute myocardial infarction. There are three mechanisms of acute mitral regurgitation in this setting: (1) mitral valve annulus dilatation due to left ventricular dilatation and dysfunction, (2) papillary muscle dysfunction usually due to inferior myocardial infarction, and (3) papillary muscle rupture. Papillary muscle rupture typically presents as a sudden haemodynamic deterioration. Due to the abrupt and severe elevation of left atrial pressure, the murmur is often soft. The severity of mitral regurgitation is best assessed by colour Doppler-echocardiography. The most frequent cause of partial or total papillary muscle rupture is a small infarct of the posteromedial papillary muscle in the right or circumflex artery distribution.117,118 In some patients transoesophageal echocardiography may be necessary to clearly establish thediagnosis.

Cardiogenic shock and pulmonary oedema with severe mitral regurgitation require emergency surgery. Intra-aortic balloon pump placement is helpful during preparation115 and coronary angiography should be performed.

Valve replacement is the procedure of choicefor rupture of the papillary muscle, although repair can be attempted in selected cases.119 If there isno rupture of the papillary muscle mechanical reperfusion of the infarct-related artery can be attempted.

Arrhythmias and conduction disturbances

Arrhythmias and conduction disturbances are extremely common during the early hours after myocardial infarction. In some cases, such as ventricular tachycardia, ventricular fibrillation and total atrioventricular block, these are life threatening and require immediate correction. Often arrhythmias are a manifestation of a serious underlying disorder, such as continuing ischaemia, pump failure, altered autonomic tone, hypoxia, electrolyte (e.g. hypokalaemia) and acid-base disturbances, that requires attention and corrective measures. The necessity for treatment and itsurgency depend mainly upon the haemodynamic consequences of the rhythm disorder.

Ventricular arrhythmias

Ventricular ectopic rhythms

Ventricular ectopic beats are almost universal on the first day, and complex arrhythmias (multiform complexes, short runs, or the R-on-T phenomenon) are common. Their value as predictors of ventricular fibrillation is questionable. No specific therapy is required.

Ventricular tachycardia

Runs of non-sustained ventricular tachycardia may be well tolerated and do not necessarily require treatment. More prolonged episodes may causehypotension and heart failure and may degenerate into ventricular fibrillation. Beta-blockers, unless contraindicated, are the first line of therapy. If the estimated risk for (recurrent) ventricular fibrillation is high, lidocaine is usually the drug of first choice: an initial loading dosage of 1mg.kg−1of intravenous lidocaine may be followed by half this dose every 8–10min to a maximum of 4mg.kg−1or a continuous infusion (1–3mg.min−1). Intravenous amiodarone (5mg.kg−1in the first hour to be followed by 900 to 1200mg.24h−1) may besuperior, however, especially in patients withrecurrent sustained ventricular tachycardia requiring cardioversion or in the case of ventricularfibrillation. Countershock is indicated if haemodynamically significant ventricular tachycardia persists. If no defibrillator is available, a precordial thump is worth trying.

It is important to differentiate true ventricular tachycardia from accelerated idioventricular rhythm, usually a harmless consequence of reperfusion, in which the ventricular rate is less than 120beats.min−1.

Ventricular fibrillation

Immediate defibrillation should be performed. The recommendations of the international guidelines 2000 for cardiopulmonary resuscitation andemergency cardiovascular care should be followed.21,22

Supraventricular arrhythmias

Atrial fibrillation complicates some 15–20% of myocardial infarctions, and is frequently associated with severe left ventricular damage and heart failure. It is usually self-limited. Episodes may last from minutes to hours, and are often repetitive. In many cases, the ventricular rate is not fast, the arrhythmia is well tolerated, and no treatment is required. In other instances, the fast rate contributes to heart failure and prompt treatment is needed. Beta-blockers and digoxin are effective in slowing the rate in many cases, but amiodarone may be more efficacious in terminating the arrhythmia.120 Countershock may also be used, but should only be employed if mandatory, since recurrences are so common.

Other supraventricular tachycardias are rare and usually self-limited. They may respond to carotid sinus pressure. Beta-blockers may be effective, if not contra-indicated, but verapamil is not recommended. Intravenous adenosine may be considered in this setting, if atrial flutter is ruled out and the haemodynamic status is stable; the ECG should be monitored during administration. Countershock should be employed if the arrhythmia is poorly tolerated.

Sinus bradycardia and heart block

Sinus bradycardia is common in the first hour,especially in inferior infarction. In some cases, opioids are responsible. It may be accompanied by quite severe hypotension, in which case it should be treated by intravenous atropine, starting with a dosage of 0.3–0.5mg, repeated up to a total of 1.5–2.0mg. Later in the course of myocardialinfarction, it is usually a favourable sign andrequires no treatment. Occasionally it may, however, be associated with hypotension. If it then fails to respond to atropine, temporary pacing may be advisable.

First-degree heart block needs no treatment

Type I second degree (Mobitz I or Wenckebach) AV (atrio-ventricular) block is usually associated with inferior infarction and seldom causes adverse haemodynamic effects. Should it do so, however, atropine should be given first; if this fails, pacing should be instituted.

Type II second degree (Mobitz II) and complete AV block are indications for the insertion of a pacing electrode, certainly if bradycardia causes hypotension or heart failure. If the haemodynamic disturbance is severe, consideration should be given to AV sequential pacing. The development of a new bundle-branch block or hemiblock usually indicates extensive anterior infarction. There is a high likelihood both for developing complete AV block as well as pump failure. The preventive placement of a temporary pacing wire may be warranted. Asystole may follow AV block, bi- or trifas-cicular block, or electrical countershock. Ifa pacing electrode is in place, pacing should be attempted. Otherwise, chest compression andventilation should be initiated, and transthoracic pacing started.

A transvenous pacing electrode should beinserted, as discussed above, in the presence of advanced AV block, and considered if bifascicular or trifascicular block develop. Some cardiologists prefer the subclavian route but this should be avoided following fibrinolysis or in the presence of anticoagulation. Alternative sites should be chosen in this situation.

Routine prophylactic therapies in the acute phase


Convincing evidence of the effectiveness of aspirin was demonstrated by the ISIS-2 trial,23 in whichit was shown that the benefits of aspirin andstreptokinase were additive.

There are few contra-indications to the use of aspirin, but it should not be given to those with a known hypersensitivity, bleeding peptic ulcer, blood dyscrasia, or severe hepatic disease. Aspirin may occasionally trigger bronchospasm in asthmatics. Unlike the situation with fibrinolysis, there is no clear evidence of a relationship between effectiveness and the time from the onset of symptoms. Nonetheless, aspirin should be given to all patients with an acute myocardial infarction as soon as possible after the diagnosis is deemed probable. This represents about 85–95% of those sustaining a myocardial infarction.

Anti-arrhythmic drugs

Although it has been demonstrated that lidocaine can reduce the incidence of ventricular fibrillation in the acute phase of myocardial infarction,121,122 this drug significantly increases the risk of asystole.122 A meta-analysis of 14 trials showed anon-significantly higher mortality in lidocaine-treated patients than in controls.123 The routine prophylactic use of this drug is not justified.


Many trials of intravenous beta-blockade havebeen undertaken in the acute phase of myocardial infarction, because of their potential to limit infarct size, reduce the incidence of fatal arrhythmias, and to relieve pain. Pooling of 28 trials124 of intravenous beta-blockade reveals an absolute reduction of mortality at 7 days from 4.3% to 3.7% or six lives saved per 1000 treated. These studies were conducted prior to the use of fibrinolytic agents or the performance of primary PCI. Two randomized trials of intravenous beta-blockade were undertaken since the widespread use of fibrinolysis.125,126 The number of events was too small to allow conclusions to be drawn. A post-hoc analysis of the use of atenolol in the GUSTO-I trial and a systematic review do not support the routine early intravenous use of beta-blockers.127,128 As discussed below, the use of beta-blockade in the acute phase of infarction in many countries is extremely low. There is a good case for the greater use of an intravenous beta-blocker when there is tachycardia (in the absence of heart failure), relative hypertension, or pain unresponsive to opioids. It may be prudent to test the patient's response to this form of therapy by first using a short-acting preparation. In most patients, however, oral beta-blockade will suffice.


A meta-analysis of 10 trials of early intravenous nitrate therapy conducted in 2041 patients showed a significant mortality reduction of about one-third.129 Each of the trials was small and with only 329 deaths in all, the results, although highly significant, had wide confidence limits. The GISSI-3130 trial tested a strategy of routine intravenous administration of nitrates vs selected administration because of ongoing ischaemia in 19 394 patients. No significant reduction in mortality was observed with the routine administration. The ISIS-4 trial,131 in which oral mononitrate was administered acutely and continued for 1 month, also failed to show a benefit. Furthermore, a benefit was not seen in the ESPRIM trial of molsidomine,132 a nitric oxide donor. The routine use of nitrates in the initial phase of myocardial infarction has, therefore, not convincingly been shown to be of value and is, therefore, not recommended.

Calcium antagonists

A meta-analysis of trials involving calcium antagonists early in the course of acute myocardial infarction showed a non-significant adverse trend.133 There is no case for using calciumantagonists for prophylactic purposes in the acute phase of myocardial infarction.

Angiotensin-converting enzyme (ACE) inhibitors

It is now well established that ACE inhibitors should be given to patients who have an impaired ejection fraction or who have experienced heart failure in the early phase. The GISSI-3,130 ISIS-4131 and Chinese Study134 have shown that ACE inhibitors started on the first day reduce mortality in the succeeding 4–6 weeks by a small but significant amount. The CONSENSUS II study,135 however, failed to show a benefit. This may have been due to the play of chance, or the fact that treatment was initiated early with an intravenous formulation. A systematic overview of trials of ACE inhibition early in acute myocardial infarction indicated that this therapy is safe, well tolerated and associated with a small but significant reduction in 30-day mortality with most of the benefit observed in the first week.131 There is now general agreement on starting ACE inhibitors in the first 24h if no contraindications are present.136 Opinions still differ as to whether to give ACE inhibitors to all patients or to high-risk patients only.


A meta-analysis of trials of magnesium therapy in acute myocardial infarction suggested a significant benefit,137,138 but the subsequent large ISIS-4trial131 did not support this, although it has been argued that the magnesium regimen in ISIS-4was not optimal. The large, recently presentedMAGIC trial confirmed the lack of benefit ofmagnesium.139


There is experimental and limited clinical evidence that routine administration of glucose-insulin-potassium may favourably influence metabolism in the ischaemic myocardium and therefore confer a clinical benefit. Meta-analysis of the available data in 1928 patients suggests a 28% reduction in hospital mortality (95% CI, 10–43%). The number of lives saved per 1000 patients treated was 49 (95% CI, 14–83).140 Whether this inexpensive treatment should be routinely recommended depends on the results of an ongoing large mortality trial.

Routine prophylactic therapies in the acute phase
RecommendationsClass IIIaIIbIIILevel of evidence
•Aspirin: 150–325mg (no enteric-coated formulation)XA
•Intravenous beta-blocker: for all patients in whom it is not contraindicatedXA
Oral beta-blockers: cfr. infra
•ACE inhibitors: oral formulation on first day
to all patients in whom it is not contraindicatedXA
to high-risk patientsXA
•Calcium antagonistsXB
•Lidocaine XB

Management of specific types of infarction

Right ventricular infarction

The recognition of right ventricular infarction is important because it may manifest itself as cardiogenic shock, but the appropriate treatmentstrategy is quite different from that for shock due to severe left ventricular dysfunction.

Right ventricular infarction may be suspected by the specific, but insensitive, clinical triad of hypotension, clear lung fields, and raised jugular venous pressure in a patient with inferior myocardialinfarction.141 ST-segment elevation in V4R is very suggestive of the diagnosis;142 this lead shouldcertainly be recorded in all cases of shock, if not done as a routine. Q waves and ST-segment elevation in V1–3also suggest the diagnosis. Echocardiography may confirm the diagnosis of right ventricular infarction by the following features: the right ventricle is dilated and hypokinetic to akinetic, the right atrium is also dilated and low velocity tricuspid regurgitation becomes significant due to tricuspid annulus dilatation.

When right ventricular infarction can be implicated in hypotension or shock, it is important to maintain right ventricular preload. It is desirable to avoid (if possible) vasodilator drugs such as the opioids, nitrates, diuretics and ACE inhibitors.Intravenous fluid loading is effective in many cases: initially, it should be administered rapidly, forexample at a rate of 200ml in 10min. It may require the infusion of 1–21 of normal saline in the first few h, and 200ml.h−1thereafter. Careful haemodynamic monitoring is required during intravenous fluid loading. Right ventricular infarction is often complicated by atrial fibrillation. This should be corrected promptly as the atrial contribution to right ventricular filling is important in this context. Likewise, if heart block develops, dual chamber pacing should be undertaken in spite of theincreased risk of catheter-induced ventricularfibrillation. There has been some question of the effectiveness of fibrinolytic therapy in right ventricular infarction,143 but it certainly seems appropriate in the hypotensive patient. Alternatively, direct PCI may result in rapid haemodynamicimprovement.144

Myocardial infarction in diabetic patients

Up to one quarter of all patients with myocardial infarction have diabetes and this figure is expected to increase. Importantly, diabetic patients may present with atypical symptoms and heart failure is a common complication. Diabetic patients who sustain a myocardial infarction still have doubled mortality compared to non-diabetic patients. There are indications that patients with diabetes do not receive the same extensive treatment as non-diabetics, presumably due to fear for treatment complications. Diabetes is not a contra-indication for fibrinolytic therapy, even in the presence of retinopathy. Furthermore, treatment with beta-blockers and ACE inhibitors seems to be even more effective than in non-diabetic patients and the risk for complications is negligible.145 The acute phase is often characterized by deterioration of the metabolic control and hyperglycaemia is an independent predictor of mortality. Strict attention to the glycaemic control by use of insulinglucose infusion followed by multiple-dose insulin treatment has been shown to reduce long-term mortality.146,147

Management of the later in-hospital course

Management of the later in-hospital phase will be determined by the amount of myocardial necrosis, the demographic characteristics of the patients and the presence or absence of co-morbidity. While the patient who became asymptomatic and with minimum myocardial damage may go home after a few days, particularly if the coronary anatomy is known, patients with significant left ventricular dysfunction or those who are at risk of new events require a longer hospitalization.


Patients with significant left ventricular damage should rest in bed for the first 12–24h, by which time it will be apparent whether the infarction is going to be complicated. In uncomplicated cases, the patient can sit out of bed late on the first day, be allowed to use a commode and undertake self-care and self-feeding. Ambulation can start the next day and such patients can be walking up to 200m on the flat, and walking up stairs within a few days. Those who have experienced heart failure, shock or serious arrhythmias should be kept in bed longer, and their physical activity increased slowly, dependent upon their symptoms and the extent of myocardial damage.

Management of specific in-hospital complications

Deep vein thrombosis and pulmonary embolism

These complications are now relatively uncommon after infarction, except in patients kept in bed because of heart failure. In such patients, they can be prevented by prophylactic doses of a low-molecular-weight heparin. When they occur they should be treated with therapeutic doses of alow-molecular-weight heparin, followed by oralanticoagulation for 3–6 months.

Intraventricular thrombus and systemic emboli

Echocardiography may reveal intraventricular thrombi, especially in patients with large anterior infarctions. If the thrombi are mobile or protuberant, they should be treated initially withintravenous unfractionated heparin or low-molecular-weight heparin and subsequently with oral anticoagulants for at least 3–6 months.


Acute pericarditis may complicate myocardialinfarction and is associated with a worse outcome. It gives rise to chest pain that may be misinterpreted as recurrent infarction or angina. The pain is, however, distinguished by its sharp nature, and its relationship to posture and respiration. The diagnosis may be confirmed by a pericardial rub. If the pain is troublesome, it may be treated by high-dose oral or intravenous aspirin, non-steroidal anti-inflammatory agents, or steroids. A haemorrhagic effusion with tamponade is uncommon and is particularly associated with anticoagulant treatment. It can usually be recognized echocardiographically. Treatment is by pericardiocentesis if haemodynamic embarrassment occurs.

Late ventricular arrhythmias

Ventricular tachycardia and ventricular fibrillation occurring on the first day have a low predictive value for recurring arrhythmias. Arrhythmiasdeveloping later are liable to recur and are associated with a high risk of death. VT or VF during the first week post infarction is associated with more extensive myocardial damage; a careful assessment of coronary anatomy and ventricular function should always be undertaken. If it is probable that the arrhythmia is induced by ischaemia, revascularization by PCI or surgery should beconsidered. If this is unlikely, a variety oftherapeutic approaches are available which are, as yet, inadequately researched. These include the use of beta-blockers, amiodarone, electro-physiologically guided antiarrhythmic therapy and/or insertion of an implantable converterdefibrillator (cfr. infra).

Post-infarction angina and ischaemia

Angina or recurrent or inducible ischaemia in the early post-infarction phase requires further investigation.

The routine use of elective PCI following fibrinolytic therapy has been compared with a conservative approach in several randomized trials.148–150 It can be concluded that routine PCI in the absence of spontaneous or provocable ischaemia does notimprove left ventricular function or survival. In treating angina or recurrent or inducible ischaemia, however, whether due to reocclusion or to aresidual stenosis, revascularization PCI or coronary artery bypass surgery) has a definite role.151 It may also be of value in managing arrhythmias associated with persistent ischaemia. Although analyses from several trials have identified a patent infarct-related vessel as a marker for good long-termoutcome, it has not been shown that late PCI with the sole aim of restoring patency influenceslate events.152 Randomized trials are currently evaluating this issue.

Coronary artery bypass surgery may be indicated if symptoms are not controlled by other means or if coronary angiography demonstrates lesions, such as left main stenosis or three-vessel disease withpoor left ventricular function, for which surgery improves prognosis.153

Risk assessment, rehabilitation and secondary prevention

Risk assessment


After acute myocardial infarction it is important to identify patients at high risk of further events such as reinfarction or death and hopefully to intervene in order to prevent these events. Because the risk of events decreases with time, early risk assessment is desirable. Clinical assessment and assessment of infarct size and resting left ventricular function will be undertaken within the first 24 to 48h but the timing of further investigation will depend upon local facilities. Traditionally, exercise electrocardiography with maximal dynamic exercise was performed within 6 weeks in order to detect inducible ischaemia. Perfusion scintigraphy using vasodilator stress and dobutamine echocardiography are more recent tools for early risk assessment. They are able to distinguish between ischaemia in remote territories and in viablemyocardium remaining in the infarct territory.Adenosine perfusion scintigraphy and stress echocardiography (vasodilator stress and dobutamine) can be performed at ±5 days and usedto guide the need for coronary angiography ordischarge and medical therapy.154

When a primary coronary intervention has been performed successfully, then early risk assessment is less important since it can be assumed that the infarct-related coronary lesion has been treated and stabilized and the main concern is to detect inducible ischaemia in other territories. Outpatient stress testing at 6 weeks using the ECG or imaging techniques would be appropriate in these patients.

Clinical assessment and further investigations

Figure 1outlines an appropriate algorithm for risk assessment after myocardial infarction and Table 6summarizes indications for imaging techniques. Clinical indicators of high risk in the acute phase include hypotension, persistent heart failure,malignant arrhythmias, and persistent chest pain or early angina on minimal exertion.155–158

View this table:
Table 5

Dosages in ACE inhibitor trials

Initial dosageTarget dosage
CONSENSUS II135 enalapril1mg i.v. enalaprilat over 2h followed by 2–5mg b.i.d. increasing to 20mg, if toleratedup to 20mg daily
GISSI-3130 lisinopril5mg initiallyup to 10mg daily
ISIS-4131 captopril6.25mg initially, 12.5mg in 2h, 25mg at 10–12hup to 50mg b.i.d.
CHINESE134 captopril6.25mg initially, 12.5mg 2h later if toleratedup to 12.5mg t.i.d.
SMILE206 zofenopril7.5mg initially, repeated after 12h and repeatedly doubled if toleratedup to 30mg b.i.d.
AIRE205 ramipril2.5mg b.i.d. increased to 5mg b.i.d. if toleratedup to 5mg b.i.d.
SAVE204 captopriltest of 6.25mg, increased if tolerated to 25mg t.i.d.up to 50mg t.i.d.
TRACE207 trandolapriltest of 0.5mgup to 4mg daily
View this table:
Table 6

Summary of indications for imaging and stress testing

At presentationWithin 48hBefore dischargeAfter dischargea
Rest echoif required for diagnosisfor LV function and thrombusfor LV function, heart failure, shock or new murmurb
Stress echofor viability and ischaemiacif not before dischargec or if primary PCI
Rest MPSif required for diagnosis
Stress MPSfor viability and ischaemiacif not before dischargec or if primary PCI
Rest RNValternative to echo for LV function
Stress ECGfor ischaemiacif not before dischargec or if primary PCI
CAGif required for primary PCIif clinical high riskif imaging high risk, medium risk with symptoms, or intractable symptoms
  • a =early risk assessment preferred

  • b =rest echo indicated at any stage for heart failure, shock or new murmur.

  • c =choice between techniques will depend upon local expertise but imaging technique preferable

  • Echo=transthoracic echocardiography or transoesophageal if required, MPS=myocardial perfusion scintigraphy, RNV=radionuclide ventriculography, CAG=coronary arteriography, PCI=percutaneous coronary intervention

Patients with high-risk clinical markers tend to be older, to have multiple risk factors, and to have had previous infarction, and they are candidatesfor early coronary angiography.159 If angiographyreveals coronary anatomy that is suitable for intervention and if there is evidence of viable myocardium that is jeopardized, then revascularization is appropriate.

Patients without high-risk clinical markers are at lower risk as a group but they still contain patients who will suffer events and further risk stratification is indicated. Although coronary angiography is often performed in these patients especially in hospitals with catheterization facilities, initial non-invasive testing is also appropriate. After the acute phase, prognosis is related to the degree of left ventricular dysfunction and the extent and severity of residual ischaemia, both of which can beassessed objectively by myocardial perfusionscintigraphy or echocardiography. Ejection fraction and end-systolic volume are strong predictors of mortality, and patients with impaired left ventricular function in particular can benefit from perfusion imaging since viable but ischaemic myocardium can be a substrate for further cardiac events.160,161

Patients at high risk by imaging criteria are those with left ventricular ejection fraction <35% or those with extensive or profound inducible ischaemia that affects more than 50% of the remaining viable myocardium. These patients should undergo coronary arteriography and be managed in the same way as those who are at high risk by clinical criteria alone.

Patients at low risk by imaging criteria are those with an ejection fraction >50% or those with limited or mild inducible ischaemia that affects less than 20% of the remaining viable myocardium, particularly if the ischaemia is in the infarct zone rather than remote. These patients can bemanaged medically unless intervention is required for symptom relief.

Patients who are at neither high nor low risk by imaging criteria can be managed according to symptomatic status. Thus, those with persistent angina that is not adequately controlled on medical therapy are candidates for coronary arteriography and possible intervention whereas those withminimal or controlled symptoms can be managed medically in the first instance.

All patients should have their metabolic risk markers measured including total, LDL- and HDL-cholesterol, fasting triglyceride, and plasmaglucose.

Assessment of myocardial viability, stunning and hibernation

The search for myocardial viability and ischaemia after infarction are complementary because only viable myocardium can be ischaemic and because the imaging techniques used to detect the two are similar. Left ventricular dysfunction after acute infarction may be due to necrosis, to stunning of viable myocardium remaining in the infarct territory, to hibernation of viable myocardium, or to a combination of all three. Simple stunning should recover within 2 weeks of the acute ischaemic insult if ischaemia does not persist, but if it does persist then recurrent stunning may become hibernation and require revascularization for recovery of function.

These concepts are of most relevance in the patient with severely impaired left ventricular function after infarction when the need for revascularization to improve function is considered. They are less relevant in the patient whose dominant symptoms are not those of left ventricular dysfunction.

Several diagnostic techniques can detect myocardial viability. Of these, it is most common touse myocardial perfusion scintigraphy or stress echocardiography initially, and to use the more complex techniques such as magnetic resonance imaging or positron emission tomography in cases of doubt.

Positron emission tomography is able to quantify myocardial perfusion using 13N-ammonia or 15O-water, and glucose metabolism using 18F-fluorodeoxyglucose.162 Conventional single photon nuclear cardiology uses uptake of thallium-201and its technetium-99m analogues to evaluate both myocardial perfusion and cell membraneviability.163 Dobutamine stress-echocardiography and magnetic resonance imaging assess resting myocardial thickness and thickening and contractile reserve.164 Resting myocardial thickness of less than 5mm indicates the absence of significantviable myocardium in the chronic setting, but this is less helpful acutely. In contrast, delayed magnetic resonance imaging after Gd-DTPA injection candefine the area of necrosis in the acute phasewith sufficient resolution to visualize subendocardial infarction. Myocardial contrast echocardiography, positron emission tomography and perfusion magnetic resonance imaging have been used with some success to assess microvascular integrity and tissue perfusion but these techniques are still investigational and are not widelyused.165–168

Evaluation of risk of arrhythmia

Holter monitoring and electrophysiological studies may be helpful in patients considered to be at high risk of arrhythmias. Heart rate variability, QT dispersion, baroreflex sensitivity, and late potentials have all been found to be of prognostic value after myocardial infarction, but further clinical experience is needed to establish whether they add substantially to the more conventional prognostic tests. Although preliminary results from the MADIT II trial showed improved survival with prophylactic implantation of a defibrillator in patients with a prior myocardial infarction and an ejection fraction of ≤30% irrespective of electrophysiological testing, further analysis is needed to determine whether the benefit was largely confined to patients who had inducible sustained ventricular arrhythmia.169


Rehabilitation is aimed at restoring the patient to as full a life as possible, including return to work. It must take into account physical, psychological and socio-economic factors. Rehabilitation is indicated in patients with significant left ventricular dysfunction. The process should start as soon as possible after hospital admission, and be continued in the succeeding weeks and months. The details of rehabilitation will not be discussed here, as full consideration of its principles and methods are dealt with in the reports of the Working Groupon Rehabilitation of the European Society ofCardiology.170

Psychological and socio-economic aspects

Anxiety is almost inevitable, both in patientsand their associates, so that reassurance andexplanation of the nature of the illness is of great importance and must be handled sensitively. It is also necessary to warn of the frequent occurrence of depression and irritability that more frequently occurs after return home. It must also be recognized that denial is common; while this may have a protective effect in the acute stage, it may make subsequent acceptance of the diagnosis more difficult. The presence or absence of a type D personality may influence the clinical course of patients with an impaired left ventricular function after myocardial infarction171 and reducing emotional distress in a rehabilitation programme may improve prognosis.172 The question of return to work and resuming other activities should be discussed prior to hospital discharge.

Lifestyle advice

The possible causes of coronary disease should be discussed with patients and their partners during hospitalization, and individualized advice on a healthy diet, weight control, smoking and exercise given.

Physical activity

All patients should be given advice with regard to physical activity based upon their recovery from the heart attack, taking into account their age, their pre-infarction level of activity, and their physical limitations. Assessment is greatly aided by a pre-discharge exercise test, which not only provides useful clinical information but can be reassuring to the over-anxious patient. A meta-analysis of rehabilitation programmes performed in the pre-reperfusion era which included exercise suggested a significant reduction in mortality.173

It should be appreciated that apart from its influence on mortality, exercise rehabilitation can have other beneficial effects, such as an increase in collaterals, as expressed in a reduction of reversible defects by thallium scintigraphy.174 Exercise capacity, cardiorespiratory fitness, perception of well-being175 have also been reported to improve, at least during the actual training period, even in elderly patients.176 The recommended frequency of exercise to attain a meaningful increase in functional status is three to five times per week. Each single-stage increase in physical work capacity is associated with a reduction in all-cause mortality risk in the range of 8%–14%.177

Thus, participation in a rehabilitation programme should be advised to all post-infarction patients with significant left ventricular dysfunction after risk assessment.

Secondary prevention


Compelling evidence from observational studies shows that those who stop smoking have a mortality in the succeeding years less than half that of those who continue to do so.178 This is, therefore, potentially the most effective of all secondary prevention measures; much effort should be devoted to this end. Most patients will not have smoked during the acute phase and the convalescent period is ideal for health professionals to help smokers quit the habit. Resumption of smoking is common after return home and continued support and advice is needed during rehabilitation. A randomized study has demonstrated the effectiveness of a nurse-directed programme:179 a smoking cessation protocol should be adopted by each hospital.

Diet and dietary supplements

The Lyon Diet Heart study has shown that a Mediterranean-type diet reduces the rate of recurrence in patients who suffered a first myocardial infarction during at least 4 years.180 All patients should be advised to take a Mediterranean-type diet low in saturated fat; high in polyunsaturated fat and high in fruit and vegetables. One study suggests that taking fatty fish at least twice a week reduces the risk of reinfarction and death.181 In another, larger trial dietary supplementation with fish oil n-3 polyunsaturated fatty acids (1g daily) but not vitamin E was associated with a significant reduction in all-cause mortality and sudden death.182 There is no evidence for the use ofsupplements of antioxidants post infarction.

Antiplatelet and anticoagulant treatment

The Antiplatelet Trialists Collaboration183 meta-analysis demonstrated about a 25% reduction in reinfarction and death in post-infarction patients. In the trials analysed, aspirin dosages ranged from 75 to 325mg daily. There is some evidence thatthe lower dosages are effective with fewer side effects.

Clinical trials undertaken before the widespread use of aspirin showed that oral anticoagulants are effective in preventing reinfarction and deathin survivors of myocardial infarction.184,185 Thepatients in these trials were randomized at least2 weeks after the index infarction. The role of routine early oral anticoagulation vs aspirin following acute myocardial infarction has been evaluated in the AFTER study.186 In such patients there wasno clear benefit over aspirin. Possibly, subsets ofpatients, e.g. those with large anterior akinesia,atrial fibrillation or echographically proven left ventricular thrombus might benefit from oral anticoagulation, but large randomized trials for these indications are lacking. Aspirin plus fixed low-dose or low-intensity oral anticoagulants are not better than aspirin alone in preventing new ischaemic events.187–189 Moderate-to-high-intensity oral anticoagulation (INR >2.0) plus aspirin, however,resulted in fewer reocclusions after successful lysis when compared with aspirin alone.190 This combination therapy was also found to reduce the composite of death, reinfarction and stroke in two recent post-infarction studies (ASPECT-2, n=993 and WARIS-2, n=3640),191–192 however at thecost of a significant increase in non-fatal bleeding complications. At present no recommendations can be made for the combined routine use oforal anticoagulants and aspirin after acute myocardial infarction. Oral anticoagulation shouldbe considered in patients who do not tolerate aspirin.

Clopidogrel, a thienopyridine, has recently been studied for secondary prevention after an acute coronary syndrome without persistent ST-segment elevation.193 No data are availableregarding the routine use of clopidogrel inaddition to aspirin following reperfusiontherapy. In patients who do not tolerate aspirin,clopidogrel is a good alternative antiplatelet therapy.194


Several trials and meta-analyses have demonstrated that beta-adrenoreceptor blocking drugs reduce mortality and reinfarction by 20–25% in those who have recovered from acute myocardial infarction.124,128,195–200 Positive trials have been conducted with propranolol, metoprolol, timolol, acebutolol and carvedilol, but studies with other beta-blockers, although not significant, are compatible with a comparable effect. A meta-analysis of 82 randomized trials provides strong evidence for long-term use of beta-blockers to reduce morbidity and mortality after acute myocardial infarction even if fibrinolytic agents have been given orACE inhibitors are co-administered.128 The significant mortality reductions observed with beta-blockers in heart failure in general, furthersupport the use of these agents after myocardial infarction. Evidence from all available studies suggests that beta-blockers should be used indefinitely in all patients who recovered from anacute myocardial infarction and without contraindications.128,199,200

Calcium antagonists

The evidence for a possible benefit of calcium antagonists is much weaker than for beta-blockers. Older trials with verapamil201 and diltiazem202have suggested that they may prevent reinfarction and death. In a trial in 874 patients with acute myocardial infarction treated with fibrinolytic agents but without congestive heart failure the 6-month use of diltiazem (300mg daily) reduced the rate of coronary interventions.203 The use of verapamil and diltiazem may be appropriate when beta-blockers are contra-indicated, especially in obstructive airways disease. Caution must be exercised in the presence of impaired ventricular function.

Trials with dihydropyridines have failed to show a benefit in terms of improved prognosis after myocardial infarction; they should, therefore, only be prescribed for clear clinical indications.133


There is no evidence that oral or transdermalnitrates improve prognosis after myocardial infarction, the ISIS-4131 and GISSI-3130 trials failingto show a benefit at 4–6 weeks after the event. Nitrates, of course, continue to be first line therapy for angina pectoris.

Angiotensin-converting enzyme (ACE) inhibitors

Several trials have established that ACE inhibitors reduce mortality after acute myocardial infarction with reduced residual left ventricular function.204–207 In the SAVE trial,204 patients were entered a mean of 11 days after the acute event if they had an ejection fraction less than 40% on nuclear imaging, and if they were free of manifest ischaemia on an exercise test. No mortality benefit was seen in the first year, but there was a 19% reduction in the succeeding 3–5 years of follow-up (from 24.6 to 20.4%). Fewer re-infarctions and less heart failure were, however, seen even within the first year.

In the AIRE trial205 patients were randomized to ramipril a mean of 5 days after the onset of a myocardial infarction that was complicated by the clinical or radiological features of heart failure. At an average of 15 months later, the mortality was reduced from 22.6% to 16.9% (a 27% relative reduction). In the TRACE study,207 patients were randomized to trandolapril or placebo a median of4 days after infarction, if they had left ventricular dysfunction as demonstrated by a wall motion index of 1.2 or less. At an average follow-up of 108 weeks, the mortality was 34.7% in the treated group and 42.3% in the placebo group. The same authors208 followed their patients for a minimum of 6 years and showed an increase in life expectancy of15.3 months (27%). Taking the three studies209together, there is a strong case for administering ACE inhibitors to patients who have experienced heart failure in the acute event, even if nofeatures of this persist, who have an ejection fraction of less than 40%, or a wall motion index of 1.2 or less, provided there are no contra-indications.

As discussed above, there is a case for administering ACE inhibitors to all patients with acute infarction from admission, provided there are no contraindications.130,131,210 Against such a policy is the increased incidence of hypotension and renal failure in those receiving ACE inhibitors in the acute stage, and the small, early, benefit in those at relatively low risk, such as patients with small inferior infarctions.

Follow-up data from the post-infarctionstudies207,209 and the data from the HOPE trial211 suggest a benefit if administration of an ACE-inhibitor is continued for at least 4 to 5 years, even in the absence of ventricular dysfunction. This benefit may even be greater in diabetics who suffered a myocardial infarction.212 A policy of continued administration of an ACE-inhibitor after myocardial infarction similar to and in combination with aspirin and a beta-blocker can bedefended if tolerated well. More support for the continued use of an ACE inhibitor after myocardial infarction may come from ongoing trials (EUROPA and PEACE).

Lipid-lowering agents

The Scandinavian Simvastatin Survival Study (4S)213 clearly demonstrated the benefits of lipid lowering in a population of 4444 anginal and/or post-infarction patients with serum cholesterol levelsof 212–308mg.dl−1(5.5–8.0mmol.1−1) afterdietary measures had been tried. Patients were not entered into the trial until 6 months after an acute infarction, and a relatively low-risk group ofpatients was recruited. Overall mortality at amedian of 5.4 years was reduced by 30% (from12% to 8%) representing 33 lives saved per 1000 patients treated over this period. There were substantial reductions in coronary mortality, and in the need for coronary bypass surgery. Patients over 60 years of age appeared to benefit as much as younger patients. Women benefited as far as major coronary events were concerned, but astatistically significant reduction in death was not demonstrated probably due to the relativelysmall number of women recruited. In the CARE study214 4159 post-infarction patients ‘with average cholesterol levels’ (mean 209mg.dl−1)received either pravastatin 40mg or placebo 3 to 20 months after the acute event. Pravastatinresulted in a relative risk reduction of fatal coronary events or confirmed myocardial (re)infarction of 24%. Similar beneficial effects were seen in a subgroup of patients who underwent myocardial revascularization.215

In the LIPID study216 around 9000 patients witha previous myocardial infarction or unstableangina and widely ranging cholesterol levels [42% ≤213mg.dl−1(5.5mmol.l−1), 44% between213–250mg.dl−1(5.5–6.4mmol.l−1), and 13% ≥251mg.dl−1(6.5mmol.l−1)] were randomized to receive either 40mg pravastatin daily or placebo, for 6 years. Pravastatin resulted in a 24% decrease in coronary deaths and a 29% reduction in the risk of myocardial (re)infarction.

In a study with gemfibrozil (a fibrate)217patients with HDL-cholesterol levels ≤40mg.dl−1(1.04mmol.l−1) but LDL-cholesterol levels ≤140mg.dl−1(3.6mmol.l−1) and triglycerides ≤300mg.dl−1(7.7mmol.l−1) were enrolled.Patients with a previous myocardial infarction benefited from gemfibrozil with a 24% reduction in death rate. In the BIP study, bezafibrate given to patients with a previous myocardial infarction or stable angina and with low (≤45mg.dl−1) HDL-cholesterol levels was associated with a non-significant 7.3% reduction in the incidence of fatal or non-fatal myocardial infarction or sudden death. A larger benefit was seen for this end-point in patients with high triglycerides at baseline.218 The key results of the various trials of lipid-lowering therapy are summarized in Tables 7 and 8.

View this table:
Table 7

Results of post-myocardial infarction patients given lipid-lowering therapy

StudyPatient number% with previous infarctionFollow-up duration in years% decrease in LDL-C% decrease in composite events% decrease in CV mortalityDrug
4S2134444795.4353233simvastatin 63%: 20mg; 37%: 40mg
CARE2154159100532 (28 vs placebo)2420pravastatin 40mg
LIPID2169014646.125 vs placebo2924pravastatin 40mg
Gemfibrozil study2172531615.1NS Increase in HDL-C 6% vs placeboa24 (all patients)24 (with previous infarction)gemfibrozil 1200mg
BIP2183090786.2NS Increase in HDL-C 18% vs placeboa7.3−7 (all patients)bezafibrate 400mg
  • a NS: not significant.

View this table:
Table 8

Initial and final lipid values after lipid-lowering therapy

Initial levelsLipid changes %
Gemfibrozil study217175±25111±2232±5161±68↓9.7a↑1.8a↑6.25a↓28.6a
  • a measured at 1 year.

  • Cholesterol levels±SD are shown in mg.dl−1and in mmol.l−1for the 4S, CARE and gemfibrozil studies. Median values with interquartile range are given for the LIPID study; ↑ or ↓: % changes over initial levels or placebo (PL); NA: no median or mean values available.

Lipid-lowering agents should be prescribed for patients who correspond to those recruited intothe trials mentioned above. In general, and inaccordance with the ESC guidelines,219 patients should be prescribed lipid-lowering therapy with statins if, in spite of dietary measures, totalcholesterol levels of ≥190mg.dl−1(4.9mmol.l−1) and/or LDL-cholesterol levels of ≥115mg.dl−1(2.97mmol.l−1) still persist. The results from the recent HPS study,220 however, suggests that statin treatment should be extended to those with even lower lipid levels, including elderly patients. In patients with low HDL-cholesterol levels, a fibrate should be considered. Controversy also exists as to how soon treatment should be started after the event. Data from a recent Swedish registry suggest that an early and aggressive treatment with lipid-lowering agents might be preferable.221

Secondary prevention
RecommendationsClass IIIaIIbIIILevel of evidence
•Stop smokingXC
•Optimal glycaemic control in diabetic patientsXB
•Blood pressure control in hypertensive patientsXC
•Mediterranean-type dietXB
•Supplementation with 1g fish oil n-3 poly-unsaturated fatty acidsXB
•Aspirin: 75 to 160mg dailyXA
If aspirin is not tolerated
clopidogrel (75mg daily)XC
oral anticoagulantXB
•Oral beta-blockers: to all patients if no contraindicationsXA
•Continuation of ACE-inhibition started on the first day (cfr. supra)XA
if in spite of dietary measures total cholesterol >190mg.dl−1and/or LDL cholesterol >115mg.dl−1XA
if HDL cholesterol ≤45mg.dl−1and triglycerides ≥200mg.dl−1XA
•Calcium antagonists (diltiazem or verapamil) if contra indications to beta-blockers and no heart failureXB
•Nitrates in the absence of anginaXA

Logistics of care

Pre-hospital care

Patient delay

The most critical time in an acute heart attack is the very early phase, during which the patient is often in severe pain and liable to cardiac arrest. Furthermore, the earlier that some treatments, notably reperfusion therapy, are given, the greater the beneficial effect. Yet, it is often an hour or more after the onset before aid is requested. Sometimes this reflects the fact that the symptoms are not severe, or typical, orabrupt in onset, but frequently immediate action is not taken even when they are. It should be a normal part of the care of patients with known ischaemic heart disease to inform them andtheir partners of the symptoms of a heart attack and how to respond to it. It is less certain what should be the role of education of the general public. Certainly, the public must be aware of how to call the emergency services, but although they have achieved some success, it is questionable whether public education campaigns have had a significant impact on outcome.222–224

Public education in cardiopulmonary resuscitation

The techniques of basic life support should be part of the school curriculum. Those most likely toencounter cardiac arrest while at work, such asthe police and fire service personnel, should be proficient in cardiopulmonary resuscitation.

The ambulance service

The ambulance service has a critical role in the management of acute myocardial infarction and cardiac arrest. The quality of the care givendepends on the training of the staff concerned. At the most simple level, all ambulance personnel should be trained to recognize the symptoms of myocardial infarction, administer oxygen and pain relief, and provide basic life support. All emergency ambulances should be equipped with defibrillators and at least one person on board trained inadvanced life support. Doctor-manned ambulances, available in only a few countries, can provide more advanced diagnostic and therapeutic skills, including the authorization to give opioids and fibrinolytic drugs. Since pre-hospital administration of fibrinolytic therapy is the most effective way to shorten delay times225 training of paramedics to undertake these functions is recommended.226

It is desirable for ambulance staff to record an ECG for diagnostic purposes and either interpret it or transmit it so that it can be reviewed by experienced staff in a coronary care unit or elsewhere. The recording of an ECG prior to admission can greatly accelerate in-hospital management.227,228

General practitioners

In some countries, general practitioners play a major role in the early care of myocardial infarction. In these countries, they are often the first to be called by patients. If they can respond quickly and have been suitably trained, they can be very effective, because they may know the individual patient, record and interpret an ECG, be able to administer opioids and fibrinolytic drugs, and undertake defibrillation.228,229

In most areas, general practitioners are not so trained. In this circumstance, although it is desirable that they attend the patient without delay, they should immediately call for an ambulance.

Admission procedures

The processing of patients once they arrive in hospital must be speedy, particularly with regard to diagnosis and the administration of fibrinolytic agents or the performance of a PCI, if indicated. In some hospitals, direct admission to a coronary care unit may be the best option, but in most, patients are first delivered to an emergency department. Delays here can be substantial; it is essential that suitably qualified staff are available to assess and treat patients with suspected myocardial infarction in this environment. Patients with clear-cut features of myocardial infarction, whose ECG demonstrate either ST-segment elevation or left bundle-branch block, should enter a ‘fast-track’ system, in which fibrinolytic therapy is instituted in the emergency department so that the ‘door-to-needle’ time is no more than 30min or in which the patient is immediately transferred to the catheterization laboratory for PCI. Other cases may require more detailed assessment which may be better undertaken in the coronary care unit.

The coronary (cardiac) care unit (CCU)

All patients with suspected myocardial infarction should initially be assessed and cared for in a designated unit, where appropriately trained staff are constantly available and where the necessary equipment for monitoring and treatment areimmediately at hand. It is important that satisfactory arrangements exist for the rapid transfer to other wards of those not needing its highly specialized facilities.

Non-invasive monitoring

Electrocardiographic monitoring for arrhythmias should be started immediately in any patient suspected of having sustained an acute myocardial infarction. This should be continued for at least 24h or until an alternative diagnosis has been made. Further ECG monitoring for arrhythmias is dependent upon the perceived risk to the patient and upon the equipment available. When a patient leaves the CCU, monitoring of rhythm may be continued, if necessary, by telemetry. More prolonged monitoring is appropriate for those who have sustained heart failure, shock or serious arrhythmias in the acute phase as the risk of further arrhythmias is high. Monitoring the recovery of ST-segment deviations or the lack thereof during the first hours following admission provides important prognostic information and may be helpful for selecting further treatment such as rescue PCI.230,231

Invasive monitoring

All coronary care units should have the skills and equipment to undertake invasive monitoring of the arterial and pulmonary artery pressures. Arterial pressure monitoring should be undertaken inpatients with cardiogenic shock. Balloon flotation catheters are of value for the assessment and care of patients with low cardiac output. They permit measurement of right atrial, pulmonary artery and pulmonary wedge pressures, and cardiac output. Balloon flotation catheters are indicated in the presence of cardiogenic shock, progressive heart failure, and suspected ventricular septal defect or papillary muscle dysfunction.

The current use of therapies tested by clinical trials

The results of clinical trials have often not been implemented in practice and treatments which have been shown to be of little or no value continue to be used widely. For instance, two recent large registry studies have demonstrated that approximately 40% of all ST-segment elevation acute myocardial infarctions did not receive reperfusion therapy.232,233 There is a great need both for continuing medical education and for ongoing auditto ensure the implementation of therapeuticadvances. The ongoing European Heart Survey and ESC guidelines implementation programmes fulfil this need. Centres which participate in multicentre clinical trials are more likely to implement evidence-based changes in clinical practice.234



Patients with a suspected heart attack have a right to expect prompt diagnosis, pain relief, resuscitation and, if indicated, reperfusion treatment.

Patients with suspected or confirmed myocardial infarction should be cared for by staff trained and experienced in modern coronary care. They should have access to advanced methods of diagnosis and treatment either at the initial place of management or following transfer to a specialist unit. They should have appropriate facilities for post-discharge follow-up, rehabilitation and secondary prevention. They and their associates should be informed of how to recognize and respond to a further heart attack.


Cardiologists, in association with emergency care physicians and health authorities, should ensure that an optimal system for the care of heartattack patients is operative in their area accordingto local resources. At the minimum level, this should include the appropriate training of ambulance personnel and first-line doctors, efficientarrangements for the diagnosis and treatment of suspected myocardial infarctions in the emergency department, and development of critical pathways for the prompt initiation of reperfusion therapy.

Cardiologists, in association with anaesthetists and other relevant specialists, should ensure that medical and paramedical hospital staff are competent in resuscitation techniques. Registers should be kept of the time from the call for care and the administration of fibrinolytic therapy (‘call-to-needle’ time) and that from hospital admission to reperfusion (‘door-to-needle’ or ‘door-to-balloon’ time). The former should be no longer than 90min and for ‘fast track’ patients with clear indications for reperfusion therapy, the ‘door-to needle’ time should not exceed 20min and the ‘door-to-balloon’ time should not exceed 60min.

Registers should also be kept of the proportion of patients with definite myocardial infarctionadmitted within 12h of the onset of symptoms with ST-segment elevation or new or presumed new left bundle-branch block who receive pharmacological and mechanical reperfusion therapy. This proportion should probably be in excess of 90%.

PCI is regarded as an alternative to fibrinolytic therapy when the appropriate skills and facilities are immediately available. The results of primary PCI should be recorded in local and nationalregisters.

Most patients with an uncomplicated infarction, especially those in whom reperfusion therapy was successful, can be discharged after 4 to 5 days.235

Appropriate strategies for assessment of future coronary risk should be implemented. This will normally include assessment of left ventricular function and one form of early stress testing (ECG, scintigraphy or echocardiography).

A rehabilitation programme should be made available for all patients, tailored to their individual needs.

There should be a policy for smoking cessation. This must consist of a continuing programme run by health professionals that not only encourages patients to stop, but endeavours to maintain cessation.

Records should be kept of secondary prevention therapy prescribed to survivors of definite myocardial infarction. Aspirin, beta-blockers and ACE inhibitors should be prescribed if no contraindications are present.

All patients should have their lipids measured, preferably on the day of admission. Those with raised lipids should first receive dietary advice. Should this fail to reduce raised lipid levels sufficiently, lipid-lowering drugs should be given,according to the criteria of the European Society of Cardiology.219

General practitioners

When general practitioners are the first point of contact for cases of suspected myocardial infarction, they must either be able to respond immediately or make provision for the emergency services to do so, or (preferably) both.

If general practitioners can respond quickly and are appropriately trained and equipped, they can provide defibrillation and fibrinolysis effectively.

They should be involved in the co-ordinatedlocal programme for the management of cardiac emergencies.

They should see patients as soon as possible after discharge from hospital, ensure that their rehabilitation is properly organized, and oversee theappropriate secondary prevention measures.

Health authorities

Health authorities should encourage the training of the public in basic cardiopulmonary resuscitation techniques and the ambulance personnel in basic and advanced life support.

They should ensure that an optimal system of care is available for patients suspected of sustaining cardiac arrest or myocardial infarction, by co-ordinating the activities of the ambulance service, general practitioners, and the hospital service.

They should ensure that emergency departments have appropriate protocols for the prompt management of patients with suspected myocardial infarction, and that there are appropriately trained staff available at all times.

They should provide sufficient beds for theintensive care of patients with myocardial infarction. Physicians with a formal training in cardiology must be available.

They should make provision for the rehabilitation of patients discharged from hospital after myocardial infarction.

They should ensure that facilities are available in their own hospital or district for the advanced investigation and treatment of patients with the complications of myocardial infarction or, if not available locally, arrangements have been made with tertiary centres elsewhere.

Procedure of the Task Force

The Task Force on the Management of AcuteMyocardial Infarction was created by the Committee for Scientific and Clinical Initiatives of the European Society of Cardiology in 1999. Individual members were invited to submit draft papers in their area of expertise and these were first discussed at a meeting in Brussels on 3 June 2000. After several revisions the members met again in Amsterdam on 30 August 2000 and in Stockholm on 5 September 2001. Specific additional contributions were obtained from K. Malmberg, H.Heidbüchel and F. Rademakers. The document was widely circulated among experts and openly discussed with the board of the European Society of Cardiology and with representatives of the national societies at a meeting held at the European Heart House on 7–8 February 2002. The final document was submitted to the Committee for Practice Guidelines (J. W. Deckers, G. De Backer, A. Parkhomenko, G. Mazzoto, W. Klein, chairman) for its approval on 20 June 2002. Invaluable assistance in processing the document was provided by Ms R. Struyven. The guidelines were developed without any involvement of the industry.


  • The full text of this document is available on the website ofthe European Society of Cardiology: www.escardio.orgin the section ‘Scientific information’, Guidelines.


  1. 1.
  2. 2.
  3. 3.
  4. 4.
  5. 5.
  6. 6.
  7. 7.
  8. 8.
  9. 9.
  10. 10.
  11. 11.
  12. 12.
  13. 13.
  14. 14.
  15. 15.
  16. 16.
  17. 17.
  18. 18.
  19. 19.
  20. 20.
  21. 21.
  22. 22.
  23. 23.
  24. 24.
  25. 25.
  26. 26.
  27. 27.
  28. 28.
  29. 29.
  30. 30.
  31. 31.
  32. 32.
  33. 33.
  34. 34.
  35. 35.
  36. 36.
  37. 37.
  38. 38.
  39. 39.
  40. 40.
  41. 41.
  42. 42.
  43. 43.
  44. 44.
  45. 45.
  46. 46.
  47. 47.
  48. 48.
  49. 49.
  50. 50.
  51. 51.
  52. 52.
  53. 53.
  54. 54.
  55. 55.
  56. 56.
  57. 57.
  58. 58.
  59. 59.
  60. 60.
  61. 61.
  62. 62.
  63. 63.
  64. 64.
  65. 65.
  66. 66.
  67. 67.
  68. 68.
  69. 69.
  70. 70.
  71. 71.
  72. 71a.
  73. 72.
  74. 73.
  75. 74.
  76. 75.
  77. 76.
  78. 77.
  79. 78.
  80. 79.
  81. 80.
  82. 81.
  83. 82.
  84. 83.
  85. 84.
  86. 85.
  87. 86.
  88. 87.
  89. 88.
  90. 89.
  91. 90.
  92. 91.
  93. 92.
  94. 93.
  95. 94.
  96. 95.
  97. 96.
  98. 97.
  99. 98.
  100. 99.
  101. 100.
  102. 101.
  103. 102.
  104. 103.
  105. 104.
  106. 105.
  107. 106.
  108. 107.
  109. 108.
  110. 109.
  111. 110.
  112. 111.
  113. 112.
  114. 113.
  115. 114.
  116. 115.
  117. 116.
  118. 117.
  119. 118.
  120. 119.
  121. 120.
  122. 121.
  123. 122.
  124. 123.
  125. 124.
  126. 125.
  127. 126.
  128. 127.
  129. 128.
  130. 129.
  131. 130.
  132. 131.
  133. 132.
  134. 133.
  135. 134.
  136. 135.
  137. 136.
  138. 137.
  139. 138.
  140. 139.
  141. 140.
  142. 141.
  143. 142.
  144. 143.
  145. 144.
  146. 145.
  147. 146.
  148. 147.
  149. 148.
  150. 149.
  151. 150.
  152. 151.
  153. 152.
  154. 153.
  155. 154.
  156. 155.
  157. 156.
  158. 157.
  159. 158.
  160. 159.
  161. 160.
  162. 161.
  163. 162.
  164. 163.
  165. 164.
  166. 165.
  167. 166.
  168. 167.
  169. 168.
  170. 169.
  171. 170.
  172. 171.
  173. 172.
  174. 173.
  175. 174.
  176. 175.
  177. 176.
  178. 177.
  179. 178.
  180. 179.
  181. 180.
  182. 181.
  183. 182.
  184. 183.
  185. 184.
  186. 185.
  187. 186.
  188. 187.
  189. 188.
  190. 189.
  191. 190.
  192. 191.
  193. 192.
  194. 193.
  195. 194.
  196. 195.
  197. 196.
  198. 197.
  199. 198.
  200. 199.
  201. 200.
  202. 201.
  203. 202.
  204. 203.
  205. 204.
  206. 205.
  207. 206.
  208. 207.
  209. 208.
  210. 209.
  211. 210.
  212. 211.
  213. 212.
  214. 213.
  215. 214.
  216. 215.
  217. 216.
  218. 217.
  219. 218.
  220. 219.
  221. 220.
  222. 221.
  223. 222.
  224. 223.
  225. 224.
  226. 225.
  227. 226.
  228. 227.
  229. 228.
  230. 229.
  231. 230.
  232. 231.
  233. 232.
  234. 233.
  235. 234.
  236. 235.
View Abstract