European Heart Journal Advance Access originally published online on August 22, 2006
European Heart Journal 2006 27(20):2440-2447; doi:10.1093/eurheartj/ehl185
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Short QT syndrome: clinical findings and diagnostic–therapeutic implications
1 Department of Cardiology, Cardinal Massaia Hospital, Asti, Italy
2 Department of Medicine-Cardiology, University Hospital Mannheim, Germany
3 Division of Cardiology, Hopital Nord, Marseille, France
4 Division of Cardiology, Hospital, Aosta, Italy
5 Federation of Cardiology, University Hospital Rangueil, Toulouse, France
6 Division of Cardiology, Lahti Central Hospital, Lahti, Finland
7 Hopital Cardiologique du Haut-Leveque, Bordeaux-Pessac, France
Received 7 February 2006; revised 4 July 2006; accepted 20 July 2006; online publish-ahead-of-print 22 August 2006.
* Corresponding author. Tel: +39 0141 487121; fax: +39 0141 487134. E-mail address: cgiustetto{at}mac.com
See page 2382 for the editorial comment on this article (doi:10.1093/eurheartj/ehl223)
 |
Abstract |
|---|
 Top Abstract IntroductionMethodsResultsDiscussionConclusionsReferences |
|---|
Aims Clinical presentation, occurrence of sudden infant death, and results of the available therapies in the largest group of patients with short QT syndrome (SQTS), studied so far, are reported.
Methods and results Clinical history, physical examination, electrocardiogram (ECG), exercise stress testing, electrophysiological study, morphological evaluation, genetic analysis and therapy results in 29 patients with SQTS and personal and/or familial history of cardiac arrest are reported. The median age at diagnosis was 30 years (range 4–80). In all subjects, structural heart disease was excluded. Eighteen patients were symptomatic (62%): 10 had cardiac arrest (34%) and in 8 (28%) this was the first clinical presentation. Cardiac arrest had occurred in the first months of life in two patients. Seven patients had syncope (24%); 9 (31%) had palpitations with atrial fibrillation documented even in young subjects. At ECG, patients exhibited a QT interval 
320 ms and QTc 340 ms. Fourteen patients received an implantable cardioverter-defibrillator (ICD) and 10 hydroquinidine prophylaxis. At a median follow-up of 23 months (range 9–49), one patient received an appropriate shock from the ICD; no patient on hydroquinidine had sudden death or syncope.
Conclusion SQTS carries a high risk of sudden death and may be a cause of death in early infancy. ICD is the first choice therapy; hydroquinidine may be proposed in children and in the patients who refuse the implant.
Key Words: Short QT syndrome • Sudden death • Ion channelopathies • SIDS
|
Introduction |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionConclusionsReferences |
|---|
Although the association between QT prolongation and sudden death has been known since the 1950s,1–3 it has become necessary to wait until recent years to understand that short QT may also be related to an increased risk of sudden death. In fact, only recently the association between a familial history of sudden death4 or atrial fibrillation (AF)5 with a short QT interval has been recognized and short QT syndrome (SQTS) identified as a genetic disorder.6–8
Only one case of aborted sudden infant death has been reported to date,4 but, in general little is known about the clinical presentation of SQTS, because the published data includes only a small number of patients.4,5,7–10
The aim of this study was to evaluate the clinical presentation, the occurrence of sudden infant death, the electrocardiographic (ECG) morphology, the prevalence of the known genetic mutations, and the results of the available therapies at a mid-term follow-up in a relatively large group of patients with SQTS.
|
Methods |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionConclusionsReferences |
|---|
Inclusion criteria
This is an observational study designed to be partly prospective and partly retrospective. A total of 29 patients, 25 belonging to eight families and four sporadic cases (Figure 1), who had personal and/or a family history of sudden death or aborted sudden death and ECG documentation of short QT interval, were included in the study. Three out the these 29 patients were included after sudden death, having ECG documentation of short QT. The number of patients initially assessed was 14. After the screening of their family members, this number increased to 29. All patients gave their consent to the study protocol.
|
In the families, there were another 12 cases of sudden death without available ECG (Figure 1). For this reason, these subjects were not included in the study group. However, because all of them were apparently healthy people, who died suddenly, most <40 years of age, the association with SQTS may be hypothesized (Figure 1).
A value of QT/QTp=80% (where QTp is the predicted QT value following Rautaharju's formula),11 as previously reported,12 was chosen as the upper limit for short QT. These patients, all Caucasian, were referred to our institution from different countries. Familial and personal medical histories, paying particular attention to the cases of sudden infant death, were collected from each patient. The patients underwent an extensive evaluation, including physical examination, exercise stress testing, ECG, and cardiac magnetic resonance (MR), in order to rule out structural heart disease. Blood samples were taken to exclude any electrolyte abnormalities and to perform a genetic analysis.
QT measurement
The QT interval was evaluated in all 12-lead ECGs. The QT interval was measured at a speed of 25 or 50 mm/s and with a 200% magnification, usually in V2, by two independent examiners. The QT was manually measured as the time interval between QRS onset and the point at which the isoelectric line intersected a tangential line drawn at the maximum downslope of the T-wave. The QT interval was corrected for the heart rate using Bazett's formula (QTc).13
The QT interval at different heart rates during the stress test was compared with the expected QT intervals using the Framingham linear regression formula,14 as Bazett's formula may not be appropriate for correcting the QT interval for short cardiac cycle lengths.
Electrophysiological study
After informed written consent was obtained, a detailed electrophysiological study was carried out. Ventricular programmed stimulation was performed at two ventricular sites (right ventricular apex and outflow tract) at two or three different pacing cycle lengths, with two to three extrastimuli up to refractoriness, without any limits for the shortest coupling interval. Atrial programmed stimulation was performed at a pacing cycle length of 600 ms in the high lateral right atrium.
Therapeutic approach
The implant of an automatic implantable cardioverter-defibrillator (ICD) was proposed to all the patients, except the young children. In these latter patients, the decision to implant an ICD was considered after taking into account the weight and the age as well. The young children and the patients who refused the implant were treated with hydroquinidine, which had already been proved to prolong the QT interval in a previous study.12
Follow-up
The patients underwent regular outpatient visits at the reference centre.
Statistical analysis
Quantitative data was expressed as a mean±SD or as a median, range, and interquartile range (IQR) as appropriate. Statistical analysis was performed using STATA® software (8.0). The probability of survival free from cardiac arrest, from birth and before the age of 40 years or before pharmacological therapy, was assessed using the Kaplan–Meier product-limit estimates. To assess the presence of predictors of the occurrence of cardiac arrest before therapy and accounting for possible within-group correlation, a shared frailty Cox proportional hazard regression model (latent familiar-level random effect) based on 12 clusters (eight families and one group for each sporadic patient) was fitted. The Cox model was used to estimate hazard ratios (HR) and corresponding 95% CI according to the potential prognostic variables sex and QTc.
All tests performed were two-sided and statistical significance level was set at 0.05.
|
Results |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionConclusionsReferences |
|---|
Clinical characteristics
Of the 29 patients, 21 were males and eight females. The median age at diagnosis was 30 years (IQR: 18–49 years; range 4–80). At the time of inclusion in the study, 18 out of 29 patients (62%) were symptomatic. Nine patients had a history of cardiac arrest (31%), resuscitated in six, two of whom had serious neurological damage. In eight of these nine patients cardiac arrest was the first clinical presentation. It occurred in patients from 4 months to 62 years of age. One more case of cardiac arrest was observed during the follow-up (patient IV, family B). The survival probability free from a first cardiac arrest is reported in Figure 2.
|
Six of the 29 patients had syncope and one patient pre-syncope (24%). In four (14%), this was the first clinical presentation. In three patients syncope was prolonged and resuscitation attempts were performed by bystanders; one episode occurred in an infant at 8 months of age (Table 1).
|
Nine patients (31%) had palpitations, with AF or flutter documented in seven (24%). In five patients (17%), AF was the first clinical manifestation. Two subjects had AF before 20 years of age, whereas in the other five AF occurred after 40 years of age. Frequent ventricular extrasystoles were documented in five patients.
Electrocardiography
The number of analysed ECGs for each patient was 1–8 with a median of 3 (IQR 2–5). In all the available ECGs, the QT/QTp interval was always <80%, with an absolute QT interval 320 ms, ranging from 210 to 320 ms, and a QTc 340 ms, varying from 250 to 338 ms. In most cases, the T-wave showed a narrow, peaked, high voltage, and symmetrical appearance and an ST-segment was almost absent (Figure 3). No relationship was observed between the T-wave amplitude and the prognosis, as cardiac arrest was observed both in subjects with high peaked T-waves and in the few subjects without high peaked T-waves.
|
The QTc interval was 300±20 ms in the 10 patients with cardiac arrest and 309±19 ms in the other 19 patients.
The sex and the QTc interval were evaluated in a multivariable analysis to assess the presence of predictors of the occurrence of cardiac arrest. Neither the sex (P=0.275), nor the QTc interval (P=0.319) resulted to be significantly related to cardiac arrest. Syncope was not evaluated as a possible predictor of cardiac arrest, because the patients who presented syncope were subsequently treated.
Thirteen patients underwent an exercise stress test. A physiological heart rate increase was observed in all patients. Heart rate at rest was 71±9 b.p.m., with a QT interval of 273±19 ms. The maximum heart rate was 148±32 b.p.m., with a mean QT interval of 233±27 ms. With increasing heart rate, only a slight further reduction of the QT interval was observed and its values tended to be closer to the expected values.
Electrophysiological study
Eighteen patients underwent an electrophysiological study. The ventricular effective refractory period (ERP) at the right ventricular apex at a cycle length of 600–500 ms varied between 140 and 180 ms (mean 155±12 ms) and at a pacing cycle of 430–400 ms varied between 130 and 180 ms (mean 150±13 ms). Programmed ventricular stimulation was performed with two to three premature stimuli up to refractoriness, except in two patients in which extrastimuli <180 ms were not used. Ventricular fibrillation was induced in 11 out of the 18 patients (61%): three had a history of aborted sudden death, four had syncope, two experienced palpitations, and two were asymptomatic. In seven patients, ventricular fibrillation was not induced: four were asymptomatic; two had a previous resuscitated cardiac arrest (in these two patients, two extrastimuli on two pacing cycle lengths up to 180 ms were used) and one patient was symptomatic for syncope, but later had a ventricular fibrillation interrupted by the ICD (this patient was studied using three extrastimuli on three pacing cycle lengths up to refractoriness).
As only three patients out of six with documented ventricular fibrillation were induced, the sensitivity of electrophysiological study was 50%.
Atrial ERPs were measured in the high lateral right atrium in 12 patients and at a cycle length of 600 ms varied between 120 and 180 ms, with a mean of 157±22 ms.
Genetics and other diagnostic tests
Genetic screening was performed in all the eight families and in the sporadic patient I and III; HERG mutation (encoding for IKr) was found in two families (A and B, Figure 1), whereas none of the known mutations were found in six families and in the two sporadic patients. Concerning the other patients, the parents of the sporadic patient II have refused it and the sporadic patient IV died before genetic screening could be performed (Table 1).
The ECG was normal in all the patients. Eight patients underwent cardiac MR, which was normal in all of them.
Therapeutic approach
Of the 29 patients, three died before clinical evaluation, 14 received an ICD and 12 patients did not receive an implant as two patients were very young children and 10 patients refused the implant. The ICD was implanted in nine patients who had ventricular fibrillation induced at electrophysiological study. Of the other five patients, two had a previous resuscitated cardiac arrest, one had a history of syncope and two were asymptomatic. Seven patients who did not receive the ICD were started on hydroquinidine, as well as another three patients implanted with an ICD, who were symptomatic for episodes of AF. Of the 10 patients who received hydroquinidine, five had HERG mutation; these patients had an increase in the QTc from 289±14 to 405±26 ms, with a change score of 116±18 ms. Moreover, in these patients an ST-segment became more evident and the T-waves increased in duration and decreased in amplitude (Figure 4). An electrophysiological study performed during therapy showed a mean ventricular ERP increase from 150±12 ms to a mean of 200±21 ms, with a change score of 66±11 ms. In these patients ventricular fibrillation was not induced any more. In the other five patients without HERG mutation, the QTc increment was lower and less homogeneous, varying from 307±22 ms to 352±41 ms, with a change score of 45±25 ms. In this latter group, only the two patients with the higher QTc increase underwent an electrophysiological study during therapy: the ventricular ERP increased, respectively, from 160 to 200 ms and from 150 to 190 ms. Also in these patients ventricular fibrillation was not induced any more.
|
Children
Three children had aborted sudden death or syncope during infancy: patient III, family A; sporadic patient II and patient IV, family B.
Patient III, family A was observed at the age of 6 years. He had severe neurological damage as a consequence of aborted sudden death at the age of 8 months. An ECG recorded at the age of 35 months showed, at HR 120 b.p.m., a QT interval of 240 ms (QTc 339 ms, QT/QTp 80%). When he was 6 years old, he had, at HR 76 b.p.m., a QT interval of 260 ms (QTc 293 ms, QT/QTp 70%). He did not undergo an electrophysiological study because of the severe neurological damage; he was genotyped (HERG mutation).
The sporadic patient II was observed at the age of 4 years. She had an aborted sudden death at the age of 4 months. The child had two episodes of cardiac arrest treated with resuscitation manoeuvres; one of these occurred in the hospital and ventricular fibrillation was documented at ECG. When she was 8 months old an ECG showed, at HR 128 b.p.m., a QT interval of 210 ms (QTc 307 ms, QT/QTp 73%). An ECG recorded at the age of 35 months showed the following values: HR of 143 b.p.m., QT interval of 210 ms (QTc 324 ms, QT/QTp 78%). An electrophysiological study was tried when the child was 6 months old. The study had to be interrupted because ventricular fibrillation was induced twice by mechanical stimulation during catheter positioning. The genetic screening was not performed because of the parents' refusal.
The values of QT and QTc of these two children are below the minimum value for children of the same age reported in literature.11,15
Patient IV, family B experienced a syncope at the age of 8 months. SQTS was diagnosed at the age of 15 years; at this age, an ECG showed, at HR 80 b.p.m., a QT of 260 ms (QTc 300 ms, QT/QTp 71%). At the electrophysiological study there was no induction of ventricular arrhythmias. He received an ICD due to the short QT interval and the family history of sudden death over three generations. One year later he had an appropriate ICD discharge at night.16 He has HERG mutation.
In the families studied there were two other babies which died suddenly: the infant which died at 3 months in family A and the one which died at 4 months in family C. These babies are shown in the family trees in Figure 1, but were not included in the study as they had no investigations performed during life, including ECG, as they were healthy.
Follow-up
For the 26 surviving patients included in the study, the median follow-up was 23 months (IQR: 20–35 months; range: 9–49). No patient died. Patient IV, family B, with a history of syncope and not inducible ventricular fibrillation, had an appropriate ICD intervention. In three patients, drug therapy was discontinued due to enteric side effects: two patients with an ICD did not receive any further antiarrhythmic therapy; the other one was a child (patient III, family A) with severe neurological sequelae due to a previous cardiac arrest and he was treated with flecainide and nadolol. The median follow-up of the seven patients in hydroquinidine was 29 months (IQR: 22–36 months; range 21–36).
None of the patients on hydroquinidine had documented or symptomatic AF episodes.
|
Discussion |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionConclusionsReferences |
|---|
Only in recent years an inherited short QT interval has been identified as a cause of familial sudden death.4 As only a few families with different clinical histories are available, many questions remain unanswered. Little is known about what is the symptom prevalence associated with SQTS, what is the first clinical manifestation and at what age it can occur, what are the QT interval limits in the affected subjects, the role of the electrophysiological study in the stratification of the risk of sudden death, and the efficacy of the available therapies. This study analyses the clinical characteristics of 29 patients with SQTS, which up to now has been the largest group of patients reported.
Cardiac arrest was the most frequent symptom and the most frequent first clinical presentation. It was also observed in the first year of life, suggesting that this new ion channel disease may be one of the causes of the sudden infant death syndrome (SIDS). Syncope was observed less frequently and it occurred at any age. The most likely mechanism of syncope in SQTS, as in other channelopathies, is self-terminating VT/VF episodes.
Patients often presented palpitations, which were not only related to AF, but also to ventricular extrasystoles. AF was also observed in young patients and should presumably be related to the presence of short ERPs in the atria.
Concerning the ECG, in the first publication relating a short QT interval to familial sudden death, two families were described with QT and QTc 300 ms.4 In this larger cohort of patients, the QT interval ranges from values as short as 210 ms to values of 320 ms; similarly the QTc varies from 250 to 340 ms. The multivariable analysis did not indicate the QTc interval as a significant risk factor for the occurrence of cardiac arrest, although it would be reasonable to suppose that a shorter QTc could predispose to a higher risk of ventricular arrhythmias. However, the absence of statistical significance might depend on the low number of patients.
A short QT interval is easier to recognize at low heart rates, whereas with increasing heart rates it tends to be closer to the normal values, as was observed, for example, during the exercise stress test. However, the QT values are still always below the normal values also at higher rates and this also makes possible the diagnosis in infants, who typically show high heart rates. This is particularly important considering that sudden death occurs also in the first months of life. It is likely that infants affected by SQTS could be identified by an ECG performed in the first months of life, as can be seen for those with long QT syndrome.15 Besides the QT interval, also the T-wave morphology appears to be very important in order to identify short QT patients. High, peaked, and narrow T-waves particularly in the precordial leads appear to be the typical morphology of T-waves in congenital SQTS.
The electrophysiological study showed extremely short ERPs at both atrial and ventricular level. It is well known that short refractory periods cause a reduction in the wavelength (the product of refractory period and conduction velocity) and this might in itself explain atrial and ventricular vulnerability to arrhythmias. A heterogeneous shortening of the action potential duration among the different cell types spanning the ventricular wall has been proposed as an additional mechanism for re-entry responsible for tachycardia/fibrillation in SQTS.17 Ventricular fibrillation was induced in most patients, however, the sensitivity of the electrophysiological study appears low and thus its value in defining the risk of sudden death in this population remains uncertain as the lack of ventricular fibrillation induction does not allow us to predict a good prognosis.
As far as genetics is concerned, mutations in three different genes have been linked to the SQTS until now: two different missense mutations in KCNH2 (HERG), the gene encoding for IKr, the rapidly activating delayed rectifier potassium channel, causing a gain of function in the channel,6 two mutations in KCNQ1 (KvLQT1), causing a gain of function in IKs, the slowly activating delayed rectifier potassium channel7,18 and a mutation in KCNJ2 (Kir2.1), causing a gain of function in IK18. However, the prevalence of these mutations does not seem high, as a mutation in HERG was found in only two of the families described in this study and neither a mutation in KCNQ1 nor in KCNJ2 was present in any of them. It is thus reasonable to suppose that mutations involving other genes will be identified in the future, similarly to what happened in long QT syndrome. The small number of genotyped families and the presence of a history of sudden death in all families does not allow us, up to now, to conclude that the genetic screening may help in identifying high-risk patients.
Because of the high incidence of sudden cardiac death, at the present time the implant of an ICD is the first choice therapy in patients with SQTS.4 However, an ICD implant in very young children is technically difficult and is associated to a higher risk of complications through life compared with adults and, moreover, some patients refuse the implant. In these cases, hydroquinidine has been proposed, as it prolongs the QT interval and the ventricular ERPs and prevents ventricular arrhythmias induction in patients with HERG mutation.12 However, in this study it was observed that patients without HERG mutation show a lower and less homogeneous QTc increment. In these patients, the effectiveness of hydroquinidine should be evaluated on the basis of individual cases. A quinidine test showing a marked QT interval prolongation could suggest a high probability of HERG mutation and could be useful in identifying potential responders to the drug.
|
Conclusions |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionConclusionsReferences |
|---|
SQTS is a genetic arrhythmogenic disorder with a high incidence of sudden death during life including the first months of life, and therefore should be considered as a possible cause of SIDS. The inheritance is autosomal dominant, with genetic heterogeneity. The diagnosis of short QT can be made with an ECG and it should always be considered in the presence of a family history of sudden death, particularly a history of sudden death in infants. It should also be considered in patients with idiopathic AF at a young age and in patients with syncope and a structurally normal heart. The outcome of SQTS patients becomes relatively safe when they are identified and treated. Unfortunately, without therapy the outcome is not so good. For this reason today, subjects with SQTS and family history of sudden death must be treated with ICD in primary prevention. At the moment there is no information on the prevalence of short QT in the general population. Further studies should also clarify whether subjects with short QT identified in a community-based survey have the same risk.
Conflict of interest: none declared.
|
References |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionConclusionsReferences |
|---|
- Jervell A and Lange-Nielsen F. (1957) Congenital deaf-mutism, functional heart disease with prolongation of the QT interval and sudden death. Am Heart J 54:59–68.[CrossRef][Web of Science][Medline]
- Romano C, Gemme G, Pongiglione R. (1963) Aritmie cardiache rare dell'età pediatrica. Clin Pediatr 45:656–615.
- Ward OC. (1964) A new familial cardiac syndrome in children. J Irish Med Assoc 54:103–106.[Medline]
- Gaita F, Giustetto C, Bianchi F, Wolpert C, Schimpf R, Riccardi R, Grossi S, Richiardi E, Borggrefe M. (2003) Short QT syndrome. A familial cause of sudden death. Circulation 108:965–970.
[Abstract/Free Full Text] - Gussak I, Brugada P, Brugada J, Wright RS, Kopecky SL, Chaltman BR, Bjerregaard P. (2000) Idiopathic short QT interval: a new clinical syndrome? Cardiology 94:99–102.[CrossRef][Web of Science][Medline]
- Brugada R, Hong K, Dumaine R, Cordeiro J, Gaita F, Borggrefe M, Menendez TM, Brugada J, Pollevick GD, Wolpert C, Burashnikov E, Matsuo K, Sheng Wu Y, Guerchicoff A, Bianchi F, Giustetto C, Schimpf R, Brugada P, Antzelevitch C. (2004) Sudden death associated with short QT syndrome linked to mutations in HERG. Circulation 109:30–35.
[Abstract/Free Full Text] - Bellocq C, van Ginneken AC, Bezzina CR, Alders M, Escande D, Mannens MM, Barò I, Wilde AA. (2004) Mutation in the KCNQ1 gene leading to the short QT-interval syndrome. Circulation 109:2394–2397.
[Abstract/Free Full Text] - Priori GS, Pandit SV, Rivolta I, Barenfeld O, Ronchetti E, Dhamoon A, Napoletano C, Anumowo J, Raffaele di Barletta M, Gaudapakkam S, Bosi G, Stramba-Badiale M, Jalife J. (2005) A novel form of short QT syndrome (SQT3) is caused by a mutation in the KCNJ2 gene. Circ Res 96:800–807.
[Abstract/Free Full Text] - Schimpf R, Wolpert C, Gaita F, Giustetto C, Borggrefe M. (2005) Short QT syndrome. Cardiovasc Res 67:357–366.
[Abstract/Free Full Text] - Wolpert C, Schimpf R, Giustetto C, Antzelevitch C, Cordeiro J, Dumaine R, Brugada R, Hong K, Gaita F, Borggrefe M. (2005) Further insights into the effect of quinidine in short QT syndrome caused by a mutation in HERG. J Cardiovasc Electrophysiol 16:1–5.
- Rautaharju PM, Zhou SH, Wong S, Calhoun H, Berenson GS, Prineas R, Davignon A. (1992) Sex differences in the evolution of the electrocardiographic QT interval with age. Can J Cardiol 8:690–695.[Web of Science][Medline]
- Gaita F, Giustetto C, Bianchi F, Schimpf R, Haissaguerre M, Calò L, Brugada R, Antzelevitch C, Borggrefe M. (2004) Short QT syndrome: pharmacological treatment. J Am Coll Cardiol 43:1294–1299.
- Bazett HC. (1920) An analysis of the time-relations of electrocardiograms. Heart 7:35–70.
- Sagie A, Larson MG, Goldberg RJ, Bengtson JR, Levy D. (1992) An improved method for adjusting the QT interval for heart rate (the Framingham Heart Study). Am J Cardiol 70:797–801.[CrossRef][Web of Science][Medline]
- Mc Cammon RW. (1961) A longitudinal study of electrocardiographic intervals in healthy children. Acta Pediatrica 50:2–52.
- Schimpf R, Bauersfeld U, Gaita F, Wolpert C. (2005) Short QT-syndrome: successful prevention of sudden cardiac death in an adolescent by implantable cardioverter-defibrillator treatment for primary prophylaxis. Heart Rhythm 2:416–417.[CrossRef][Web of Science][Medline]
- Extramiana F and Antzelevitch C. (2004) Amplified transmural dispersion of repolarization as the basis for arrhythmogenesis in a canine ventricular-wedge model of short-QT syndrome. Circulation 110:3661–3666.
[Abstract/Free Full Text] - Hong K, Piper DR, Diaz-Valdecantos A, Brugada J, Oliva A, Burashnikov E, Santos-de-Soto J, Grueso-Montero J, Diaz-Enfante E, Brugada P, Sachse F, Sanguinetti MC, Brugada R. De novo KCNQ1 mutation responsible for atrial fibrillation and short QT syndrome in utero. Cardiovasc Res Published online ahead of print August 16, 2005.
CiteULike 
Connotea 
Del.icio.us What's this?
Related articles in EHJ:
- Short QT syndrome and arrhythmogenic cardiac diseases in the young: the challenge of implantable cardioverter-defibrillator therapy for children
- Giuseppe Boriani, Mauro Biffi, Cinzia Valzania, Gabriele Bronzetti, and Cristian Martignani
EHJ 2006 27: 2382-2384.[Extract] [FREE Full Text]
This article has been cited by other articles:
|
|
 |
|
  Developed in collaboration with, European Heart Rhythm Association (EHRA), Heart Failure Association (HFA), and Heart Rhythm Society (HRS), Endorsed by the following societies, European Society of Emergency Medicine (EuSEM), European Federation of Internal Medicine (EFIM), European Union Geriatric Medicine Society (EUGMS), American Geriatrics Society (AGS), European Neurological Society (ENS), et al. Guidelines for the diagnosis and management of syncope (version 2009): The Task Force for the Diagnosis and Management of Syncope of the European Society of Cardiology (ESC) Eur. Heart J., November 1, 2009; 30(21): 2631 - 2671. [Full Text] [PDF]
|
|
|
|
 |
|
 P. Kirchhof, J. Bax, C. Blomstrom-Lundquist, H. Calkins, A. J. Camm, R. Cappato, F. Cosio, H. Crijns, H.-C. Diener, A. Goette, et al. Early and comprehensive management of atrial fibrillation: Proceedings from the 2nd AFNET/EHRA consensus conference on atrial fibrillation entitled 'research perspectives in atrial fibrillation' Europace, July 1, 2009; 11(7): 860 - 885. [Full Text] [PDF]
|
|
|
|
 |
|
 R M Campbell, S Berger, and J Drezner Sudden cardiac arrest in children and young athletes: the importance of a detailed personal and family history in the pre-participation evaluation Br. J. Sports Med., May 1, 2009; 43(5): 336 - 341. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 F. G. Cosío, J.#x. Palacios, A.#x.;n Pastor, and A. Núñez CHAPTER 2 The Electrocardiogram ESC Textbook of Cardiovascular Medicine, January 1, 2009; 2(1): med-9780199566990-chapter - med-9780199566990-chapter. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. J. Camm, P. Kirchhof, G. Y.H. Lip, I. Savelieva, and S. Ernst CHAPTER 29 Atrial Fibrillation ESC Textbook of Cardiovascular Medicine, January 1, 2009; 2(1): med-9780199566990-chapter - med-9780199566990-chapter. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. E. Lehnart, M. J. Ackerman, D. W. Benson Jr, R. Brugada, C. E. Clancy, J. K. Donahue, A. L. George Jr, A. O. Grant, S. C. Groft, C. T. January, et al. Inherited Arrhythmias: A National Heart, Lung, and Blood Institute and Office of Rare Diseases Workshop Consensus Report About the Diagnosis, Phenotyping, Molecular Mechanisms, and Therapeutic Approaches for Primary Cardiomyopathies of Gene Mutations Affecting Ion Channel Function Circulation, November 13, 2007; 116(20): 2325 - 2345. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. A. Stephenson and C. I. Berul Electrophysiological Interventions for Inherited Arrhythmia Syndromes Circulation, August 28, 2007; 116(9): 1062 - 1080. [Full Text] [PDF]
|
|
|
|
|
|
O. Anttonen, M.J. Junttila, H. Rissanen, A. Reunanen, M. Viitasalo, and H.V. Huikuri Prevalence and Prognostic Significance of Short QT Interval in a Middle-Aged Finnish Population Circulation, August 14, 2007; 116(7): 714 - 720. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. G. Reinig and T. R. Engel The Shortage of Short QT Intervals Chest, July 1, 2007; 132(1): 246 - 249. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. E. Hunt and F. R. Hauck Sudden infant death syndrome Can. Med. Assoc. J., April 24, 2007; 176(9): 1309 - 1310. [Full Text] [PDF]
|
|
|
|
|
|
C. Antzelevitch, G. D. Pollevick, J. M. Cordeiro, O. Casis, M. C. Sanguinetti, Y. Aizawa, A. Guerchicoff, R. Pfeiffer, A. Oliva, B. Wollnik, et al. Loss-of-Function Mutations in the Cardiac Calcium Channel Underlie a New Clinical Entity Characterized by ST-Segment Elevation, Short QT Intervals, and Sudden Cardiac Death Circulation, January 30, 2007; 115(4): 442 - 449. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. Boriani, M. Biffi, C. Valzania, G. Bronzetti, and C. Martignani Short QT syndrome and arrhythmogenic cardiac diseases in the young: the challenge of implantable cardioverter-defibrillator therapy for children Eur. Heart J., October 2, 2006; 27(20): 2382 - 2384. [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||