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European Heart Journal Advance Access published online on July 8, 2008
European Heart Journal, doi:10.1093/eurheartj/ehn302
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Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2008. For permissions please email: journals.permissions@oxfordjournals.org

Left atrial linear lesions are required for successful treatment of persistent atrial fibrillation

Sébastien Knecht*, Mélèze Hocini, Matthew Wright, Nicolas Lellouche, Mark D. O’Neill, Seiichiro Matsuo, Isabelle Nault, Vijay S. Chauhan, Kevin J. Makati, Michela Bevilacqua, Kang-Teng Lim, Frederic Sacher, Antoine Deplagne, Nicolas Derval, Pierre Bordachar, Pierre Jaïs, Jacques Clémenty and Michel Haïssaguerre

Service de Rythmologie, Hôpital Cardiologique du Haut-Lévêque, CHU de Bordeaux/Université Victor Segalen Bordeaux II, Bordeaux-Pessac, France

Received 28 February 2008; revised 9 May 2008; accepted 12 June 2008.

* Corresponding author. Tel: +33 5 57 65 64 71, Fax: +33 5 57 65 65 09, Email sebastien.knecht{at}chu-brugmann.be


   Abstract
Top
 Abstract
Introduction
 Methods
 Results
 Discussion
 Conclusion
 Funding
 References
 
Aims: This study evaluates the clinical outcome and incidence of left atrial (LA) macro re-entrant atrial tachycardia (AT) in patients in whom persistent atrial fibrillation (AF) terminated during catheter ablation without the need of roof and mitral lines.

Methods and results: Persistent AF was terminated by ablation in 154 of 180 consecutive patients. AF history was 60 months including 11 months of continuous AF. Patients were divided into two groups: those who had not required both LA linear lesions to terminate AF (group A, 85 patients), and those who had (group B, 69 patients). There was no difference in clinical and echocardiographic characteristics between both groups except for a shorter duration of continuous AF in group A (9 vs.12 months, respectively) (P = 0.03). After 28 months of follow-up, the incidence of LA macro re-entrant AT necessitating linear ablation was higher in group A (76%) compared with group B (33%) (P = 0.002). When complete linear block could not be achieved during the index procedure, the incidence of subsequent roof (P = 0.008) or mitral isthmus (P = 0.010) dependent macro re-entrant AT was higher.

Conclusion: Although persistent AF can be terminated by catheter ablation without linear lesions, the majority will require linear lesions for macro re-entrant AT.

Key Words: Atrial fibrillation • Linear lesions • Mitral isthmus line • Roof line • Substrate ablation • Atrial tachycardia • Macro re-entry


   Introduction
Top
 Abstract
 Introduction
Methods
 Results
 Discussion
 Conclusion
 Funding
 References
 
Catheter ablation has emerged as a realistic therapeutic option for symptomatic atrial fibrillation (AF).1 The three main techniques described for ablation of persistent AF include pulmonary vein (PV) isolation,2,3 ablation based on electrogram analysis,4–7 and left atrial (LA) linear lesions.8–14 The combination of PV isolation and either electrogram-based ablation or LA lines has been shown to increase the efficacy of catheter ablation for paroxysmal and persistent AF.8–16 The most common LA linear lesions are the roof line which connects the two superior PVs17 and the mitral line which joins the mitral annulus to the PV either anteriorly or laterally.12,18 The ideal endpoint of linear lesions should be complete electrical block;10,12,17,19,20 however, this is technically challenging, time consuming, and potentially hazardous.10,12,21,22 These issues have led to some investigators to reserve linear lesions only for macro re-entrant atrial tachycardia (AT) occurring after AF termination. It is unknown, however, whether this strategy reduces the overall requirement for linear lesions for persistent AF.

This study evaluates the incidence of LA macro re-entrant AT and clinical outcome of patients in whom persistent AF was terminated by catheter ablation without the need of performing both roof and mitral linear lesion sets.


   Methods
Top
 Abstract
 Introduction
 Methods
Results
 Discussion
 Conclusion
 Funding
 References
 
Study population
Between March 2005 and July 2007, 180 consecutive patients underwent catheter ablation of drug refractory and symptomatic persistent AF. Persistent AF was defined as AF which is sustained beyond 7 days, or lasting <7 days but necessitating pharmacological or electrical cardioversion, as per the HRS/EHRA/ECAS consensus statement.23 The endpoint of the ablation procedure was AF termination using a sequential approach which included PV isolation, electrogram-based ablation, and, if necessary, linear lesions (roof line first followed by mitral isthmus line if the patients remained in AF).

Of the 180 patients, AF could not be terminated by catheter ablation in 26 (14%). Both LA linear lesions were performed in these 26 patients and all of them subsequently required antiarrhythmic medication and/or external cardioversion to restore sinus rhythm.

The 154/180 patients (86%) in whom AF terminated during the ablation procedure were classified into two groups: (i) group A: those who had not required both LA linear lesions during AF (i.e. no line or only the roof line but not a mitral line) and (ii) group B: those who had required both LA lines during AF. The characteristics and clinical outcome of both groups were compared.

Electrophysiological study
All patients provided written informed consent. Antiarrhythmic drugs, with the exception of amiodarone, were withdrawn at least five half- lives before the procedure. Oral anticoagulation (target INR, 2–3) was maintained for at least 1 month prior to the procedure, and all patients underwent transoesophageal echocardiography within 48 h prior to the procedure to exclude the presence of atrial thrombus.

Electrophysiological studies were performed in the fasting state using mild sedation. The following catheters were introduced via the right femoral vein: (i) a steerable decapolar catheter (5 mm electrode spacing, Xtrem, ELA Medical, Le-Plessis-Robinson, France) was positioned within the coronary sinus (CS); (ii) a 10-polar circumferential mapping catheter (Lasso, Biosense Webster, Diamond Bar, CA, USA) was introduced in the LA and stabilized using a long sheath (SL 0, Saint-Jude Medical, MN, USA) that was continuously perfused with heparinized saline; and (iii) a 3.5 mm externally irrigated-tip ablation catheter (Thermocool, Biosense Webster) for ablation.

AF was induced at the start of the procedure if the patient was in sinus rhythm, by burst atrial pacing. Following transseptal access to the LA, a single bolus of heparin (50 IU/kg) was administered. Surface electrocardiograms and bipolar endocardial electrograms were continuously monitored and stored on a computer-based digital amplifier/recorder system with optical disk storage for off-line analysis (Bard Electrophysiology). Intracardiac electrograms were filtered from 30 to 500 Hz and measured with computer-assisted callipers at a sweep speed of 100 mm/s. The operator was protected with a dedicated radiation protection cabin (Cathpaxw, Lemer Pax, Carquefou, France).24

Ablation protocol
Radiofrequency (RF) ablation was performed in temperature-controlled mode with a target tip temperature limit of 42°C. Power settings of 20–35 W were used with manual titration of the saline perfusate ranging from 10–60 mL/min to achieve the desired power. Ablation was preferentially performed with the distal electrode parallel to the targeted atrial tissue rather than perpendicular in order to minimize the risk of steam popping25 and to allow electrograms to be recorded from the proximal electrode.

The effect of ablation was monitored by repeated evaluation of the AF cycle length (AFCL) until termination of AF as described previously.21 The AFCL was determined within both appendages prior and after each ablation step by averaging 30 consecutive cycles using automated monitoring software (Labsystem Pro, Bard Electrophysiology).26 The automated annotation of electrogram peaks were manually verified and corrected (if necessary) using online callipers at a sweep speed of 100 mm/s.

The apex of both appendages was selected for the accurate measurement of AFCL because of unambiguous high-voltage electrograms in contrast to the usually chaotic activity in the atrium.26 LA appendage cycle length was measured by positioning the ablation catheter in the LA appendage, whereas the 10-polar circumferential mapping catheter was positioned in the right atrial (RA) appendage after PV isolation for continuous monitoring of the RA cycle length.

Catheter ablation sequence

  1. PV isolation was performed using RF applications to eliminate electrograms as described previously.27
  2. Electrogram-based ablation was performed in the LA and the CS at all sites displaying any of the following electrogram features potentially representing arrhythmogenic tissue28,29: (a) complex fractionated atrial electrograms, especially continuous electrograms; (b) sites with a significant electrogram offset between the distal and proximal recording bipoles of the mapping catheter (gradient of activation) suggesting a local re-entrant wavefront; (c) regions with a cycle length shorter than the mean LA appendage AFCL (frequency gradient). Three-dimensional electroanatomical mapping systems quantifying complex fractionated atrial electrograms were not used because initial validation studies were based on visual assessment.5,6 In addition, a recent study demonstrated a similar value of automatic compared with visual assessment.30 If complex fractionated electrograms were ubiquitous in the LA and the CS, the regions that have the greatest influence in the AF process were first targeted, i.e. the base of the LA appendage and the inferior LA–CS interface.28 Ablation at all of these atrial sites was performed for 20–60 s. The endpoint of ablation in each region was transformation of complex fractionated electrograms into discrete electrograms and slowing of local cycle length compared with LA appendage length or elimination of electrograms. The RF delivery was also stopped after 60 s of application. Finally, when atrial activity had a consistent activation sequence with a varying cycle length focal sources (defined as a site with radial spread of activation to the surrounding tissue, i.e. centrifugal activation) were targeted.31
  3. If AF persisted following PV isolation and electrogram-based ablation, linear ablation was carried out. The roof line was performed first followed by the mitral line if AF persisted. Briefly, the roof line was carried out cranially at the LA roof using three different approaches17: (a) the catheter was aligned perpendicular to the roof and moved between both the superior PVs; (b) the catheter was looped around the LA to the left superior PV and was then pulled back to the right superior PV, keeping the catheter parallel to the roof; and (c) the catheter was directed towards the left superior PV and the sheath towards the right PV (or vice versa), also keeping the catheter parallel to the roof. The mitral line was carried out by positioning the ablation catheter at the ventricular side of the lateral mitral isthmus (atrial-to-ventriculogram ratio 1:1) and then turning the sheath and ablation catheter clockwise to reach the left inferior PV. During AF, the endpoint of linear ablation was significant reduction (<75%) or abolition of local electrograms on the line. After restoration of sinus rhythm, lines were checked for bidirectional block, with additional ablation if necessary. Complete block of mitral and roof lines was confirmed by observing the reversal of the expected activation sequence at one side of the line while pacing from the other side12,17 as follows: while pacing from LA appendage, activation of the LA posterior wall was ascending with a complete roof line (instead of descending with an incomplete line),15 and the CS sequence was activated proximal to distal with a complete mitral line (instead of distal to proximal if incomplete).12 Differential pacing was also used to exclude slow conduction on the mitral line.12,32
  4. The RA and superior vena cava were targeted for ablation if implicated as a source perpetuating AF and only after all LA ablation steps. The RA was mapped when LA ablation produced a lesser prolongation of AFCL in the RA, resulting in a left–right fibrillatory cycle gradient.26

Atrial fibrillation termination and subsequent atrial tachycardia mapping and ablation
Termination of AF was defined as a transition directly from AF to sinus rhythm or via one or more intermediately occurring ATs. No induction manoeuvres were attempted after AF termination, as the great majority of patients with persistent AF are inducible at the end of the index procedure, without predicting further arrhythmia recurrence.33

AF was defined as beat-to-beat variability in cycle length and morphology, whereas AT was defined as an organized atrial rhythm with a consistent endocardial activation sequence in both atria and a monomorphic P-wave on surface ECG. Macro re-entrant AT was defined by sequential mapping of the entire tachycardia cycle length within one chamber and entrainment manoeuvres. Perimitral macro re-entrant AT was defined demonstrating the entire tachycardia cycle around the mitral annulus and entrainment at two or more circuit sites displaying a post-pacing interval of no longer than 20 ms of the tachycardia cycle length. Similarly, roof-dependent macro re-entrant AT was diagnosed demonstrating the entire cycle within the LA either around the right or left PVs and entrainment at two or more circuits sites displaying a post-pacing interval of no longer than 20 ms than the tachycardia cycle length. Focal AT was defined as consistent activity originating from one atrial segment and spreading out centrifugally to the rest of the atrial tissue. Focal AT was either focal point AT or localized re-entry depending on local electrogram characteristics.34,35 Catheter ablation of these ATs was performed until restoration of sinus rhythm occurred.

Follow-up
Patients remained in hospital for 2 days following the ablation procedure. In addition to routine follow-up by the referring cardiologist, patients were hospitalized at 3, 6, 9, and 12 months following the ablation procedure for clinical interview and ambulatory 24 h monitoring. Antiarrhythmic medication was discontinued after the ablation procedure except in the case of arrhythmia recurrence, where the previously ineffective drug was used (or amiodarone in the presence of structural heart disease). A repeat ablation procedure was undertaken beyond a 3 month blanking period in the event of arrhythmia recurrence that was refractory to drug and external cardioversion. Warfarin anticoagulation was continued for at least 6 months after the last procedure. When patients had been asymptomatic and in sinus rhythm for 1 year, they were followed up by their referring cardiologist at 6 monthly intervals. The last time point for follow-up was scheduled in April 2008, and additional ambulatory 24 h monitoring and clinical interview were performed within the last 3 months of follow-up.

Statistical analysis
Continuous variables are expressed as mean ± SD except for count and time variables which are expressed as median and interquartile (IQ) range. Statistical significance was assessed using the unpaired Student’s t-test or Mann–Whitney test if necessary. Categorical variables, expressed as numbers or percentages, were analysed with the {chi}2 test or Fisher’s exact test. All tests were two-tailed and a P-value < 0.05 was considered statistically significant. Cumulative event rates (i.e. occurrence of subsequent arrhythmia) were calculated according to the Kaplan–Meier method.


   Results
Top
 Abstract
 Introduction
 Methods
 Results
Discussion
 Conclusion
 Funding
 References
 
Patients’ characteristics
Persistent AF was terminated during the first ablation procedure in 154 patients. These patients (132 males) were aged 56 ± 10 years (28–80) and were refractory to two (IQ range 1–3) antiarrhythmic drugs and three (IQ range 2–4) external cardioversions. Forty-two patients (27%) were treated with amiodarone within 3 months preceding the procedure. The time since the initial diagnosis of AF was 60 months (IQ range 36–116), and AF had been continuous for 11 months (IQ range 6–25). Seventy patients (45%) had structural heart disease, and 22 (14%) had heart failure at the time of the procedure. Left ventricular ejection fraction was 57% (IQ range 49–67), with a left ventricular diastolic diameter of 52 mm (IQ range 48–57) and an LA antero-posterior diameter of 47 mm (IQ range 44–51).

Procedural results
LA and RA appendages cycle lengths prior to ablation were 156 ms (IQ range 140–168) and 154 ms (IQ range 139–165), respectively. The total procedural, fluoroscopic, and RF delivery durations were 240 min (IQ range 200–270), 71 min (IQ range 69–90), and 81 min (IQ range 68–96), respectively. RF delivery for electrogram-based ablation was 27 min (IQ range 17–33), including ablation inside the CS in 108 patients (70%). One patient developed cardiac tamponade requiring pericardiocentesis and two patients had volume overload that required treatment with diuretics without long-term sequelae.

AF termination occurred before performing both roof and mitral lines in 85/154 patients (55%) (group A). Conversely, 69/154 patients (45%) required two LA linear lesions to terminate persistent AF (group B).

The only parameter associated with the necessity of both linear lesions to achieve termination of AF was the duration of continuous AF [9 (IQ range 5–18) vs. 12 months (IQ range 7–24), respectively] (P = 0.03) (Table 1).


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  		Table 1 Parameters associated with the necessity of linear lesions to achieve termination of AF

 
Atrial tachycardia occurring after atrial fibrillation termination
In 130/154 patients (84%), AF terminated to one or more AT instead of direct sinus rhythm restoration. There were 87 focal ATs and 92 LA macro re-entrant ATs (mean 1.4 AT per patient). Focal ATs were located in CS/inferior LA interface (18 patients), LAA (18 patients), septum (11 patients), anterior LA (five patients), posterior LA (five patients), RA (one patient), and PV recurrence (eight patients). In 21 patients, after exclusion of an LA macro re-entrant AT, the exact origin of the focal AT could not be determined or confirmed by catheter ablation, and DC cardioversion (18 patients) or pace termination (three patients) was required to restore sinus rhythm.

LA macro re-entrant AT consisted of two major mechanisms: circuits involving the LA roof or the left mitral isthmus. There were 68 left mitral isthmus-dependent and 24 roof-dependent ATs. Sixteen patients had both mitral and roof macro re-entrant AT, including two patients with a ‘dual-loop’ AT.36

In group A, 53/85 patients (62%) had LA macro re-entrant AT occurrence after AF termination: three had a roof-dependent macro re-entrant AT, 37 had a perimitral macro re-entrant AT, and 12 had both. In group B, 23/69 (35%) patients had LA macro re-entrant AT occurrence: four had a roof-dependent macro re-entrant AT, 14 had a perimitral macro re-entrant AT, and five had both. The number of LA macro re-entrant ATs occurring at the index procedure was significantly higher in group A compared with group B (P = 0.02). In six patients (five perimitral and one roof dependent), linear ablation could not discontinue LA macro re-entrant AT, and subsequent DC cardioversion (four patients) or pace termination was needed. Linear lesions were subsequently attempted during sinus rhythm.

Left atrial linear lesions performed during the index procedure
In total, 146/154 patients (95%) underwent a roofline ablation during the index procedure (140 patients during AF and an additional six for roof-dependent macro re-entrant AT) (Figure 1). Conduction block was achieved in 131 of the 146 roof lines (90%) with an RF application time of 8 min (IQ range 6–11).


Figure 1
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  		Figure 1 Flow chart of the population study depicting the necessity of left atrial (LA) linear lesions during the index procedure and the follow-up. During atrial fibrillation (AF), 140/154 patients were ablated along the roof and 69/154 along the mitral isthmus. Among the 14 patients who did not require the roof line to terminate atrial fibrillation, six still required the roof line for roof-dependent atrial tachycardia during the index procedure and an additional one patient for roof-dependent atrial tachycardia during the follow-up. Among the 85 patients who did not require the mitral line to terminate atrial fibrillation, 49 required the mitral line for perimitral atrial tachycardia during the index procedure and an additional 11 patients for perimitral atrial tachycardia during the follow-up. In total, 147/154 patients were ablated at the roof line and 129/154 at the mitral line.

 
In comparison, 118/154 patients (77%) underwent a mitral line ablation during the index procedure (69 patients during AF and an additional 49 for mitral-dependent macro re-entrant AT) (Figure 1). Conduction block was achieved in 102 of the 118 mitral lines attempted (86%) with an RF application time of 18 min (IQ range 13–28). The duration of RF application for the mitral line was significantly longer compared with the roofline (P < 0.001).

Atrial tachycardia occurring during the follow-up
During a follow-up of 28 months (IQ range 23–33), 66/154 patients (43%) had AT recurrence (all resistant to antiarrhythmic drug and external cardioversion) and underwent a re-ablation procedure (1.7 procedures per patient). There were 58 focal and 57 LA macro re-entrant ATs (mean 1.7 AT per patient). Focal ATs were located at the CS/inferior LA interface (six patients), LAA (five patients), LA septum (18 patients), anterior LA (10 patients), posterior LA (two patients), RA (one patient) and PVs (14 patients). In two patients, the exact origin of the focal AT could not be ascertained and DC cardioversion was required to restore sinus rhythm.

LA macro re-entrant ATs included 32 roof-dependent and 45 left mitral isthmus–dependent ATs. Twenty patients had both mitral and roof macro re-entrant ATs. In group A, 33/85 patients (39%) had LA macro re-entrant AT recurrence, including 32 who had already required at least one LA linear lesion during the index procedure: six had a roof-dependent macro re-entrant AT, 13 had a perimitral macro re-entrant AT, and 14 had both. In group B, 24/69 (35%) patients had LA macro re-entrant AT recurrence: six had a roof-dependent macro re-entrant AT, 12 had a perimitral macro re-entrant AT, and six had both. In three patients (three perimitral), LA macro re-entrant AT could not be discontinued and required DC cardioversion. Linear lesions were subsequently completed during sinus rhythm in all.

Among the 154 patients in whom AF terminated during the ablation procedure, 126 (82%) ultimately required both a mitral line and a roof line, 21 (14%) required the roof line only, three (2%) required the mitral line only, and four (2%) required no LA linear ablation (Figure 1). In group A, 65/85 patients (76%) required an additional linear lesion for left macro re-entrant AT either acutely or within the follow-up period. In group B, the incidence of macro re-entrant was less, accounting for 24 of the 69 patients (P = 0.002, hazard ratio 1.75, 95% confidence interval 1.27–3.08) (Figure 2). Amiodarone had no impact on the occurrence of LA macro re-entrant AT (P = 0.59, hazard ratio 0.90, 95% confidence interval 0.53–1.43).


Figure 2
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  		Figure 2 Kaplan–Meier analysis of long-term freedom from left atrial macro re-entrant atrial tachycardia depending on the necessity of performing both left atrial linear lesions (group B) or not (group A) to terminate atrial fibrillation by catheter ablation.

 
In total, of the 180 patients ablated for persistent AF, 173 (96%) ultimately required the roof line and 155 (86%) the mitral line during the follow-up period.

Importance of linear electrical block
Of the 10 patients without conduction block of the roof line at the index procedure, five (50%) developed roof-dependent macro re-entrant AT. Conversely, among the 137 patients with linear block, only 24 (19%) developed roof-dependent macro re-entrant AT (P = 0.008, hazard ratio 0.3, 95% confidence interval 0.02–0.57) (Figure 3).


Figure 3
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  		Figure 3 Kaplan–Meier analysis of long-term freedom from left atrial roof-dependent macro re-entrant atrial tachycardia depending on bidirectional conduction block at the roof line during the first procedure.

 
Similarly, of the 16 patients without bidirectional conduction block of the left mitral line at the index procedure, nine (56%) developed mitral isthmus-dependent macro re-entrant AT. Conversely, among the 102 patients with linear block, only 26 (25%) developed mitral isthmus-dependent macro re-entrant AT (P = 0.010, hazard ratio 2.5, 95% confidence interval 1.39–11.48) (Figure 4). Interestingly, 12/35 patients (34%) with gap-related perimitral AT were ablated inside the CS to complete the bidirectional linear electrical block.


Figure 4
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  		Figure 4 Kaplan–Meier analysis of long-term freedom from left mitral isthmus-dependent macro re-entrant atrial tachycardia depending on bidirectional conduction block at the mitral line during the first procedure.

 
Atrial fibrillation recurrence
Among the 154 patients in whom AF terminated by catheter ablation, only nine (6%) (four in group A and five in group B) had a recurrence of AF after the first procedure: five patients (one lone AF and four with concomitant macro re-entrant ATs) had a repeat ablation and then had no further arrhythmia recurrences, three patients with paroxysmal AF with minimal symptoms are controlled by antiarrhythmic medication and one patient remains in AF but is asymptomatic and is treated with rate control. Of note, 15/154 patients (10%) who had AT recurrence despite both linear lesions (two persistent and nine paroxysmal) are still on the waiting list for a redo ablation procedure. Two patients (2%) died from terminal heart failure after 3 and 6 months of follow-up despite maintenance of sinus rhythm.


   Discussion
Top
 Abstract
 Introduction
 Methods
 Results
 Discussion
Conclusion
 Funding
 References
 
Main findings
This study highlights that although PV isolation and electrogram-based ablation without linear lesions are effective for terminating persistent AF in a significant number of patients, macro re-entrant AT requiring LA linear ablation is very likely to occur during the overall follow-up period. After a follow-up of more than 2 years, among all the patients ablated for persistent AF, 96% ultimately required a roofline and 86% a mitral line.

Macro re-entrant atrial tachycardia and atrial fibrillation ablation
Macro re-entrant AT has been shown to occur in <21% of patients after paroxysmal AF ablation,9,10,12,20,37–40 but appears more frequently in the context of persistent AF ablation.3,6,28,33 With an ablation strategy targeting only fractionated atrial electrograms, two studies reported subsequent macro re-entrant AT in 365 and 26%6 of cases. Another study demonstrated that restoration and maintenance of sinus rhythm with an approach combining PV isolation, electrogram ablation, and eventually linear lesions required ablation of subsequent AT in 75% of the cases, the majority of which were macro re-entrant circuits.28

In some of the aforementioned studies, macro re-entrant circuits have been assumed to arise from a pro-arrhythmic effect of incomplete conduction block or later partial recovery of linear lesions,12,17,19,20,41 which was also confirmed by our study. However, our study has also shown that these macro re-entrant circuits may also occur in the majority of patients without previously performed linear lesions in the long-term follow-up. The large proportion of patients that require LA lines to terminate AF and restore sinus rhythm could result from either pre-existing macro re-entrant loops potentially participating in the AF process42,43 or from macro re-entrant AT favoured by prior extensive LA ablation.9

Technical challenges when performing left atrial linear ablation
Conduction block of the roof line was reached sooner and more frequently compared with the mitral line, in agreement with earlier studies.12,17,44 Post-mortem anatomical and in vivo studies have shown that the atrial myocardium from the left inferior PV to the lateral aspect of the mitral valve has a wall thickness up to 10 mm.45 In comparison, the atrial myocardium of the LA roof is thinner, ranging between 3.5 and 6 mm in post-mortem studies.46 Numerous recesses and cavities along the left mitral isthmus have been reported,44 as well as epicardial muscular connections necessitating ablation within the CS in the majority of patients.12

The necessity of bidirectional conduction block of linear lesions and its appropriateness has been debated in the literature. Some authors suggested that complete bidirectional conduction block should not be the endpoint of a linear lesion33 despite the fact that this has been associated with a decrease in subsequent arrhythmia during follow-up.14,44 Our study confirmed that when the LA linear lesions could not be blocked, there was a significant higher risk of corresponding macro re-entrant AT recurrence. This supports the HRS/EHRA/ECAS consensus statement on the endpoint of linear lesions.23

Clinical outcome
In this study, only 6% of patients with persistent AF in whom AF was terminated by RF ablation had recurrence of AF during a follow-up of >2 years. A study has previously shown that in order to obtain such results, extensive LA ablation was necessary; however, significant improvement in atrial mechanical function and symptoms after 1 month of follow-up was also demonstrated.47 Together, using previously observed data in conjunction with the findings in the present study, AF termination may be considered a predictor of clinical success, although this requires confirmation in larger prospective studies.

Limitations
Patients characterized as having no linear lesions may have had unintended functional lines of block created by extensive electrogram abatement in the areas of the roof or mitral isthmus which might have altered the interpretation of data.

Moreover, the applied lesion set could have resulted in an ‘iatrogenic’ substrate with gap-related macro re-entrant AT. However, there is still no consensus concerning the precise moment to stop electrogram-based ablation and to move on to linear lesions ablation or to end the procedure. In a previous study that used an ablation strategy consisting of PV isolation and LA linear lesions alone, although there was a lower rate of macro re-entrant AT, AF recurrence was far higher than the present study.13 Furthermore, our study confirms that the absence of bidirectional block at linear lesions (which is not uncommon) may also create the substrate for macro re-entrant AT.

On the basis of previous studies documenting procedural efficiency regarding the performance of linear lesions,12,15,21 the roof line was performed prior to the mitral line when electrogram-based ablation failed to terminate AF. The effect of changing the order of linear lesions and potential impact on clinical outcome in this study is therefore unknown.

Finally, some patients might have some asymptomatic arrhythmia recurrences as long term Holter monitoring was not systematically used.


   Conclusion
Top
 Abstract
 Introduction
 Methods
 Results
 Discussion
 Conclusion
Funding
 References
 
LA linear ablation in combination with PV isolation and electrogram-based ablation is the main electrophysiological approach to treat persistent AF. Although PV isolation and electrogram-based ablation are effective in terminating persistent AF in some patients, further LA linear ablation will likely be required owing to macro re-entrant AT. The recurrence of AF for these patients is very low. The absence of complete linear block predicts a higher risk of macro re-entrant AT occurrence.

Conflict of interest: none declared.


   Funding
Top
 Abstract
 Introduction
 Methods
 Results
 Discussion
 Conclusion
 Funding
References
 
M.D.O’N. is supported by the British Heart Foundation, and S.K. is supported by the Belgian Foundation for Cardiac Surgery.


   References
Top
 Abstract
 Introduction
 Methods
 Results
 Discussion
 Conclusion
 Funding
 References
 

  1. Fuster V, Ryden LE, Cannom DS, Crijns HJ, Curtis AB, Ellenbogen KA, Halperin JL, Le Heuzey JY, Kay GN, Lowe JE, Olsson SB, Prystowsky EN, Tamargo JL, Wann S, Smith SC Jr, Jacobs AK, Adams CD, Anderson JL, Antman EM, Hunt SA, Nishimura R, Ornato JP, Page RL, Riegel B, Priori SG, Blanc JJ, Budaj A, Camm AJ, Dean V, Deckers JW, Despres C, Dickstein K, Lekakis J, McGregor K, Metra M, Morais J, Osterspey A, Zamorano JL. ACC/AHA/ESC 2006 Guidelines for the Management of Patients with Atrial Fibrillation: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines (Writing Committee to Revise the 2001 Guidelines for the Management of Patients with Atrial Fibrillation): developed in collaboration with the European Heart Rhythm Association and the Heart Rhythm Society. Circulation (2006) 114:e257–e354.[Free Full Text]
  2. Oral H, Knight BP, Tada H, Ozaydin M, Chugh A, Hassan S, Scharf C, Lai SW, Greenstein R, Pelosi F Jr, Strickberger SA, Morady F. Pulmonary vein isolation for paroxysmal and persistent atrial fibrillation. Circulation (2002) 105:1077–1081.[Abstract/Free Full Text]
  3. Kanagaratnam L, Tomassoni G, Schweikert R, Via S, Bash D, Beheiry S, Lesh M, Niebauer M, Saliba W, Chung M, Tchou P, Natale A. Empirical pulmonary vein isolation in patients with chronic atrial fibrillation using a three-dimensional nonfluoroscopic mapping system: long-term follow-up. PACE (2001) 24:1774–1779.[Medline]
  4. Sanders P, Berenfeld O, Hocini M, Jais P, Vaidyanathan R, Hsu LF, Garrigue S, Takahashi Y, Rotter M, Sacher F, Scavee C, Ploutz-Snyder R, Jalife J, Haissaguerre M. Spectral analysis identifies sites of high-frequency activity maintaining atrial fibrillation in humans. Circulation (2005) 112:789–797. Published online ahead of print August 2005.[Abstract/Free Full Text]
  5. Nademanee K, McKenzie J, Kosar E, Schwab M, Sunsaneewitayakul B, Vasavakul T, Khunnawat C, Ngarmukos T. A new approach for catheter ablation of atrial fibrillation: mapping of the electrophysiologic substrate. J Am Coll Cardiol (2004) 43:2044–2053.[Abstract/Free Full Text]
  6. Oral H, Chugh A, Good E, Wimmer A, Dey S, Gadeela N, Sankaran S, Crawford T, Sarrazin JF, Kuhne M, Chalfoun N, Wells D, Frederick M, Fortino J, Benloucif-Moore S, Jongnarangsin K, Pelosi F Jr, Bogun F, Morady F. Radiofrequency catheter ablation of chronic atrial fibrillation guided by complex electrograms. Circulation (2007) 115:2606–2612.[Abstract/Free Full Text]
  7. Schmitt C, Estner H, Hecher B, Luik A, Kolb C, Karch M, Ndrepepa G, Zrenner B, Hessling G, Deisenhofer I. Radiofrequency ablation of complex fractionated atrial electrograms (CFAE): preferential sites of acute termination and regularization in paroxysmal and persistent atrial fibrillation. J Cardiovasc Electrophysiol (2007) 18:1039–1046.[CrossRef][Web of Science][Medline]
  8. Kottkamp H, Tanner H, Kobza R, Schirdewahn P, Dorszewski A, Gerds-Li J-H, Carbucicchio C, Piorkowski C, Hindricks G. Time courses and quantitative analysis of atrial fibrillation episode number and duration after circular plus linear left atrial lesions: trigger elimination or substrate modification: early or delayed cure? J Am Coll Cardiol (2004) 44:869–877.[Abstract/Free Full Text]
  9. Pappone C, Manguso F, Vicedomini G, Gugliotta F, Santinelli O, Ferro A, Gulletta S, Sala S, Sora N, Paglino G, Augello G, Agricola E, Zangrillo A, Alfieri O, Santinelli V. Prevention of iatrogenic atrial tachycardia after ablation of atrial fibrillation: a prospective randomized study comparing circumferential pulmonary vein ablation with a modified approach. Circulation (2004) 110:3036–3042. Published online ahead of print November 2004.[Abstract/Free Full Text]
  10. Ernst S, Ouyang F, Lober F, Antz M, Kuck KH. Catheter-induced linear lesions in the left atrium in patients with atrial fibrillation: an electroanatomic study. J Am Coll Cardiol (2003) 42:1271–1282.[Abstract/Free Full Text]
  11. Sanders P, Hocini M, Jais P, Sacher F, Hsu L-F, Takahashi Y, Rotter M, Rostock T, Nalliah CJ, Clementy J, Haissaguerre M. Complete isolation of the pulmonary veins and posterior left atrium in chronic atrial fibrillation. Long-term clinical outcome. Eur Heart J (2007) 18:1862–1871.
  12. Jais P, Hocini M, Hsu LF, Sanders P, Scavee C, Weerasooriya R, Macle L, Raybaud F, Garrigue S, Shah DC, Le Metayer P, Clementy J, Haissaguerre M. Technique and results of linear ablation at the mitral isthmus. Circulation (2004) 110:2996–3002. Published online ahead of print November 2004.[Abstract/Free Full Text]
  13. Hsu LF, Jais P, Sanders P, Garrigue S, Hocini M, Sacher F, Takahashi Y, Rotter M, Pasquie JL, Scavee C, Bordachar P, Clementy J, Haissaguerre M. Catheter ablation for atrial fibrillation in congestive heart failure. N Engl J Med (2004) 351:2373–2383.[Abstract/Free Full Text]
  14. Gaita F, Riccardi R, Caponi D, Shah D, Garberoglio L, Vivalda L, Dulio A, Chiecchio A, Manasse E, Gallotti R. Linear cryoablation of the left atrium versus pulmonary vein cryoisolation in patients with permanent atrial fibrillation and valvular heart disease: correlation of electroanatomic mapping and long-term clinical results. Circulation (2005) 111:136–142.[Abstract/Free Full Text]
  15. Willems S, Klemm H, Rostock T, Brandstrup B, Ventura R, Steven D, Risius T, Lutomsky B, Meinertz T. Substrate modification combined with pulmonary vein isolation improves outcome of catheter ablation in patients with persistent atrial fibrillation: a prospective randomized comparison. Eur Heart J (2006) 27:2871–2878.[Abstract/Free Full Text]
  16. Martinek M, Aichinger J, Nesser H-J, Ziegler PD, Purerfellner H. New insights into long-term follow-up of atrial fibrillation ablation: full disclosure by an implantable pacemaker device. J Cardiovasc Electrophysiol (2007) 18:818–823.[CrossRef][Web of Science][Medline]
  17. Hocini M, Jais P, Sanders P, Takahashi Y, Rotter M, Rostock T, Hsu LF, Sacher F, Reuter S, Clementy J, Haissaguerre M. Techniques, evaluation, and consequences of linear block at the left atrial roof in paroxysmal atrial fibrillation: a prospective randomized study. Circulation (2005) 112:3688–3696.[Abstract/Free Full Text]
  18. Sanders P, Jais P, Hocini M, Hsu LF, Scavee C, Sacher F, Rotter M, Takahashi Y, Pasquie JL, Shah DC, Garrigue S, Clementy J, Haissaguerre M. Electrophysiologic and clinical consequences of linear catheter ablation to transect the anterior left atrium in patients with atrial fibrillation. Heart Rhythm (2004) 1:176–184.[CrossRef][Web of Science][Medline]
  19. Rostock T, O’Neill MD, Sanders P, Rotter M, Jais P, Hocini M, Takahashi Y, Sacher F, Jonsson A, Hsu LF, Clementy J, Haissaguerre M. Characterization of conduction recovery across left atrial linear lesions in patients with paroxysmal and persistent atrial fibrillation. J Cardiovasc Electrophysiol (2006) 14:14.
  20. Cummings JE, Schweikert R, Saliba W, Hao S, Martin DO, Marrouche NF, Burkhardt JD, Kilicaslan F, Verma A, Beheiry S, Belden W, Natale A. Left atrial flutter following pulmonary vein antrum isolation with radiofrequency energy: linear lesions or repeat isolation. J Cardiovasc Electrophysiol (2005) 16:293–297.[CrossRef][Web of Science][Medline]
  21. Takahashi Y, Jais P, Hocini M, Sanders P, Rotter M, Rostock T, Sacher F, Jais C, Clementy J, Haissaguerre M. Acute occlusion of the left circumflex coronary artery during mitral isthmus linear ablation. J Cardiovasc Electrophysiol (2005) 16:1104–1107.[CrossRef][Web of Science][Medline]
  22. Jais P, Shah DC, Haissaguerre M, Takahashi A, Lavergne T, Hocini M, Garrigue S, Barold SS, Le Metayer P, Clementy J. Efficacy and safety of septal and left-atrial linear ablation for atrial fibrillation. Am J Cardiol (1999) 84:139R–146R.[CrossRef][Web of Science][Medline]
  23. Calkins H, Brugada J, Packer DL, Cappato R, Chen S-A, Crijns HJG, Damiano RJ Jr, Davies DW, Haines DE, Haissaguerre M, Iesaka Y, Jackman W, Jais P, Kottkamp H, Kuck KH, Lindsay BD, Marchlinski FE, McCarthy PM, Mont JL, Morady F, Nademanee K, Natale A, Pappone C, Prystowsky E, Raviele A, Ruskin JN, Shemin RJ. HRS/EHRA/ECAS Expert Consensus Statement on Catheter and Surgical Ablation of Atrial Fibrillation: Recommendations for Personnel, Policy, Procedures and Follow-Up: A report of the Heart Rhythm Society (HRS) Task Force on Catheter and Surgical Ablation of Atrial Fibrillation. Developed in partnership with the European Heart Rhythm Association (EHRA) and the European Cardiac Arrhythmia Society (ECAS); in collaboration with the American College of Cardiology (ACC), American Heart Association (AHA), and the Society of Thoracic Surgeons (STS). Endorsed and approved by the governing bodies of the American College of Cardiology, the American Heart Association, the European Cardiac Arrhythmia Society, the European Heart Rhythm Association, the Society of Thoracic Surgeons, and the Heart Rhythm Society. Heart Rhythm (2007) 4:816–861.[CrossRef][Web of Science][Medline]
  24. Dragusin O, Weerasooriya R, Jais P, Hocini M, Ector J, Takahashi Y, Haissaguerre M, Bosmans H, Heidbuchel H. Evaluation of a radiation protection cabin for invasive electrophysiological procedures. Eur Heart J (2007) 28:183–189.[Abstract/Free Full Text]
  25. Eick OJ, Gerritse B, Schumacher B. Popping phenomena in temperature-controlled radiofrequency ablation: when and why do they occur? Pacing Clin Electrophysiol (2000) 23:253–258.[CrossRef][Medline]
  26. Haissaguerre M, Lim K-T, Jacquemet V, Rotter M, Dang L, Hocini M, Matsuo S, Knecht S, Jais P, Virag N. Atrial fibrillatory cycle length: computer simulation and potential clinical importance. Europace (2007) 9:vi64–vi70.[Abstract/Free Full Text]
  27. Haissaguerre M, Shah DC, Jais P, Hocini M, Yamane T, Deisenhofer I, Chauvin M, Garrigue S, Clementy J. Electrophysiological breakthroughs from the left atrium to the pulmonary veins. Circulation (2000) 102:2463–2465.[Abstract/Free Full Text]
  28. Haissaguerre M, Sanders P, Hocini M, Takahashi Y, Rotter M, Sacher F, Rostock T, Hsu LF, Bordachar P, Reuter S, Roudaut R, Clementy J, Jais P. Catheter ablation of long-lasting persistent atrial fibrillation: critical structures for termination. J Cardiovasc Electrophysiol (2005) 16:1125–1137.[CrossRef][Web of Science][Medline]
  29. Takahashi Y, O’Neill MD, Hocini M, Dubois R, Matsuo S, Knecht S, Mahapatra S, Lim K-T, Jais P, Jonsson A, Sacher F, Sanders P, Rostock T, Bordachar P, Clementy J, Klein GJ, Haissaguerre M. Characterization of electrograms associated with termination of chronic atrial fibrillation by catheter ablation. J Am Coll Cardiol (2008) 51:1003–1010.[Abstract/Free Full Text]
  30. Wu J, Estner H, Luik A, Ucer E, Reents T, Pflaumer A, Zrenner B, Hessling G, Deisenhofer I. Automatic 3D mapping of complex fractionated atrial electrograms (CFAE) in patients with paroxysmal and persistent atrial fibrillation. J Cardiovasc Electrophysiol (2008) in press.
  31. Haissaguerre M, Hocini M, Sanders P, Takahashi Y, Rotter M, Sacher F, Rostock T, Hsu LF, Jonsson A, O’Neill MD, Bordachar P, Reuter S, Roudaut R, Clementy J, Jais P. Localized sources maintaining atrial fibrillation organized by prior ablation. Circulation (2006) 113:616–625.[Abstract/Free Full Text]
  32. Shah D, Haissaguerre M, Takahashi A, Jais P, Hocini M, Clementy J. Differential pacing for distinguishing block from persistent conduction through an ablation line. Circulation (2000) 102:1517–1522.[Abstract/Free Full Text]
  33. Oral H, Pappone C, Chugh A, Good E, Bogun F, Pelosi F Jr, Bates ER, Lehmann MH, Vicedomini G, Augello G, Agricola E, Sala S, Santinelli V, Morady F. Circumferential pulmonary-vein ablation for chronic atrial fibrillation. N Engl J Med (2006) 354:934–941.[Abstract/Free Full Text]
  34. Sanders P, Hocini M, Jaïs P, Hsu L-F, Takahashi Y, Rotter M, Scavée C, Pasquié J-L, Sacher F, Rostock T, Nalliah CJ, Clémenty J, Haïssaguerre M. Characterization of focal atrial tachycardia using high-density mapping. J Am Coll Cardiol (2005) 46:2088–2099.[Abstract/Free Full Text]
  35. Chen SA, Chiang CE, Yang CJ, Cheng CC, Wu TJ, Wang SP, Chiang BN, Chang MS. Sustained atrial tachycardia in adult patients. Electrophysiological characteristics, pharmacological response, possible mechanisms, and effects of radiofrequency ablation. Circulation (1994) 90:1262–1278.[Abstract/Free Full Text]
  36. Shah D, Jais P, Takahashi A, Hocini M, Peng JT, Clementy J, Haissaguerre M. Dual-loop intra-atrial reentry in humans. Circulation (2000) 101:631–639.[Abstract/Free Full Text]
  37. Oral H, Scharf C, Chugh A, Hall B, Cheung P, Good E, Veerareddy S, Pelosi F Jr, Morady F. Catheter ablation for paroxysmal atrial fibrillation: segmental pulmonary vein ostial ablation versus left atrial ablation. Circulation (2003) 108:2355–2360.[Abstract/Free Full Text]
  38. Gerstenfeld EP, Callans DJ, Dixit S, Russo AM, Nayak H, Lin D, Pulliam W, Siddique S, Marchlinski FE. Mechanisms of organized left atrial tachycardias occurring after pulmonary vein isolation. Circulation (2004) 110:1351–1357. Published online ahead of print September 2004.[Abstract/Free Full Text]
  39. Villacastin J, Perez-Castellano N, Moreno J, Gonzalez R. Left atrial flutter after radiofrequency catheter ablation of focal atrial fibrillation. J Cardiovasc Electrophysiol (2003) 14:417–421.[CrossRef][Web of Science][Medline]
  40. Mesas CE, Pappone C, Lang CC, Gugliotta F, Tomita T, Vicedomini G, Sala S, Paglino G, Gulletta S, Ferro A, Santinelli V. Left atrial tachycardia after circumferential pulmonary vein ablation for atrial fibrillation: electroanatomic characterization and treatment. J Am Coll Cardiol (2004) 44:1071–1079.[Abstract/Free Full Text]
  41. Oral H, Chugh A, Lemola K, Cheung P, Hall B, Good E, Han J, Tamirisa K, Bogun F, Pelosi F Jr, Morady F. Noninducibility of atrial fibrillation as an end point of left atrial circumferential ablation for paroxysmal atrial fibrillation: a randomized study. Circulation (2004) 110:2797–2801. Published online ahead of print October 2004.[Abstract/Free Full Text]
  42. Schuessler RB, Boineau JP, Bromberg BI, Hand DE, Yamochi S, Cox JL. Normal and abnormal activation of the atrium. In: Cardiac Electrophysiology—Zipes, Jalife, eds. (1995) 2nd ed. Philadelphia, PA: Saunders. 543–562.
  43. Konings KT, Kirchhof CJ, Smeets JR, Wellens HJ, Penn OC, Allessie MA. High-density mapping of electrically induced atrial fibrillation in humans. Circulation (1994) 89:1665–1680.[Abstract/Free Full Text]
  44. Fassini G, Riva S, Chiodelli R, Trevisi N, Berti M, Carbucicchio C, Maccabelli G, Giraldi F, Bella PD. Left mitral isthmus ablation associated with PV isolation: long-term results of a prospective randomized study. J Cardiovasc Electrophysiol (2005) 16:1150–1156.[CrossRef][Web of Science][Medline]
  45. Becker AE. Left atrial isthmus: anatomic aspects relevant for linear catheter ablation procedures in humans. J Cardiovasc Electrophysiol (2004) 15:809–812.[CrossRef][Web of Science][Medline]
  46. Ho SY, Sanchez-Quintana D, Cabrera JA, Anderson RH. Anatomy of the left atrium: implications for radiofrequency ablation of atrial fibrillation. J Cardiovasc Electrophysiol (1999) 10:1525–1533.[Web of Science][Medline]
  47. Takahashi Y, O’Neill MD, Hocini M, Reant P, Jonsson A, Jais P, Sanders P, Rostock T, Rotter M, Sacher F, Laffite S, Roudaut R, Clementy J, Haissaguerre M. Effects of stepwise ablation of chronic atrial fibrillation on atrial electrical and mechanical properties. J Am Coll Cardiol (2007) 49:1306–1314.[Abstract/Free Full Text]

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