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Background and Aims: Patterns of atrial fibrillation (AF) recurrence post-catheter ablation for persistent AF (PsAF) are not well described. This study aimed to describe the pattern of AF recurrence seen following catheter ablation for PsAF and the implications for healthcare utilization and quality of life (QoL)., Methods: This was a post-hoc analysis of the CAPLA study, an international, multicentre study that randomized patients with symptomatic PsAF to pulmonary vein isolation plus posterior wall isolation or pulmonary vein isolation alone. Patients underwent twice daily single lead ECG, implantable device monitoring or three monthly Holter monitoring., Results: 154 of 333 (46.2%) patients (median age 67.3 years, 28% female) experienced AF recurrence at 12-month follow-up. Recurrence was paroxysmal in 97 (63%) patients and persistent in 57 (37%). Recurrence type did not differ between randomization groups (P = .508). Median AF burden was 27.4% in PsAF recurrence and .9% in paroxysmal AF (PAF) recurrence (P < .001). Patients with PsAF recurrence had lower baseline left ventricular ejection fraction (PsAF 50% vs. PAF 60%, P < .001) and larger left atrial volume (PsAF 54.2 ± 19.3 mL/m² vs. PAF 44.8 ± 11.6 mL/m², P = .008). Healthcare utilization was significantly higher in PsAF (45 patients [78.9%]) vs. PAF recurrence (45 patients [46.4%], P < .001) and lowest in those without recurrence (17 patients [9.5%], P < .001). Patients without AF recurrence had greater improvements in QoL as assessed by the Atrial Fibrillation Effect on Quality-of-Life (AFEQT) questionnaire (Δ33.3 ± 25.2 points) compared to those with PAF (Δ24.0 ± 25.0 points, P = .012) or PsAF (Δ13.4 ± 22.9 points, P < .001) recurrence., Conclusions: AF recurrence is more often paroxysmal after catheter ablation for PsAF irrespective of ablation strategy. Recurrent PsAF was associated with higher AF burden, increased healthcare utilization and antiarrhythmic drug use. The type of AF recurrence and AF burden may be considered important endpoints in clinical trials investigating ablation of PsAF., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Background: Linear and complex electrogram ablation (LCEA) beyond pulmonary vein isolation (PVI) is associated with an increase in left atrial macro-re-entrant tachycardias (LAMTs). Posterior wall isolation (PWI) is increasingly performed to improve AF ablation outcomes. However, the impact of PWI on the incidence of LAMT is unknown., Objectives: The purpose of this study was to establish the incidence of LAMT following PVI alone vs PVI + PWI vs PVI + PWI + LCEA., Methods: Consecutive patients undergoing catheter ablation for AF or LAMT post-AF ablation between 2008 and 2022 from 4 electrophysiology centers were reviewed with a minimum follow-up of 12 months., Results: In total, 5,619 (4,419 index, 1,100 redo) AF ablation procedures were performed in 4,783 patients (mean age 60.9 ± 10.6 years, 70.7% men). Over a mean follow-up of 6.4 ± 3.8 years, 246 procedures for LAMT were performed in 214 patients at a mean of 2.6 ± 0.6 years post-AF ablation. Perimitral (52.8% of patients), roof-dependent (27.1%), PV gap-related (17.3%), and anterior circuits (8.9%) were most common, with 16.4% demonstrating multiple circuits. The incidence of LAMT was significantly higher following PVI + PWI (6.2%) vs PVI alone (3.0%; P < 0.0001) and following PVI + PWI + LCEA vs PVI + PWI (12.5%; P = 0.019). Conduction gaps in previous ablation lines were responsible for LAMT in 28.4% post-PVI alone, 35.3% post-PVI + PWI (P = 0.386), and 81.8% post-PVI + PWI + LCEA (P < 0.005)., Conclusions: The incidence of LAMT following PVI + PWI is higher than with PVI alone but significantly lower than with more extensive atrial substrate modification. Given a low frequency of LAMT following PWI, empiric mitral isthmus ablation is not justified and may be proarrhythmic., Competing Interests: Funding Support and Author Disclosures Dr Lim is supported by a NHMRC postgraduate scholarship. Dr Ling has received grants from Abbott Australia. Dr Sugumar has received grants from the RACP Foundation. Prof Prabhu has received grants from NHMRC, University of Melbourne, and Baker Heart and Diabetes Institute; has received postdoctoral fellowship support from the Heart Foundation; has received advisory fees from Biosense Webster; and has received speaker fees from Abbott Medical. Prof Kalman is supported by an NHMRC practitioner fellowship; and has received research support from Biosense Webster and Medtronic. Prof Kistler is a recipient of an Investigatorship from the NHMRC of Australia; has received grants from Baker Department of Metabolic Health and University of Melbourne; and has received speaker fees from Abbott Medical. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2024 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Nonrandomized data suggest that longer diagnosis-to-ablation time (DAT) is associated with poorer outcomes; however, a recent randomized trial found no difference in recurrences when ablation was delayed by 12 months., Objectives: This study sought to assess the impact of DAT on atrial fibrillation (AF) recurrence in patients undergoing catheter ablation for persistent AF., Methods: CAPLA (Effect of Catheter Ablation Using Pulmonary Vein Isolation With vs Without Posterior Left Atrial Wall Isolation on Atrial Arrhythmia Recurrence in Patients With Persistent Atrial Fibrillation: The CAPLA randomized clinical trial) was a multicenter trial that randomized patients with persistent AF to pulmonary vein isolation + posterior wall isolation or pulmonary vein isolation alone. Follow-up was 12 months. Outcomes were assessed after a 3-month blanking period., Results: Median DAT in the 334 patients was 28 months (Q1-Q3: 12-66 months). Patients were divided into quartile groups: Q1 was DAT 0 to 12 months (n = 84, median DAT 7 months), Q2 was DAT 13 to 28 months (n = 85, median DAT 20 months), Q3 was DAT 29 to 66 months (n = 84, median DAT 41 months), and Q4 was DAT ≥67 months (n = 81, median DAT 119 months). AF recurrence rate was 36.9% for Q1, 44.7% for Q2, 47.6% for Q3, and 56.8% for Q4 (P = 0.082). On multivariable analysis, DAT Q4 was the only factor significantly associated with risk of recurrence (HR: 1.607; 95% CI: 1.005-2.570; P = 0.048). Median AF burden was 0% (Q1-Q3: 0%-0.47%) in Q1 and 0.33% (Q1-Q3: 0%-4.6%) in Q4 (P = 0.002). Quality of life (assessed by the Atrial Fibrillation Effect on Quality-of-Life questionnaire) improved markedly in all quartiles (Q1: Δ28.8 ± 24, Q2: Δ24.4 ± 23.4, Q3: Δ21.7 ± 26.6, Q4: Δ24.6 ± 21.4; P = 0.331)., Conclusions: In a cohort of patients with persistent AF undergoing ablation in a prospective trial with standardized entry criteria and intensive electrocardiogram monitoring, those with shorter DAT had lower rates of AF recurrence. However, differences were modest, and all quartiles demonstrated very low AF burden and improvements in quality of life., Competing Interests: Funding Support and Author Disclosures Dr Chieng was supported by a National heart foundation (NHF) Post-Doctoral Fellowship. Dr William was supported by a NHF postgraduate PhD scholarship. Dr Crowley was supported by a Baker Institute PhD scholarship. Dr Segan was supported by a cofunded National Health and Medical Research Council (NHMRC)/NHF postgraduate PhD scholarship. Dr Kalman has received research and fellowship support from Medtronic, Abbott, Zoll, and Biosense Webster. Dr Kistler has received an Investigator grant from the NHMRC; received funding for consultancy and speaking engagements from Abbott Medical; and served on the advisory board with fellowship support from Biosense Webster. Dr Sanders has served on the advisory board for Medtronic, Abbott Medical, CathRx, Pacemate, and Boston Scientific; and received a practitioner fellowship from the NHMRC and NHF. Dr Lee has received consulting fees from Biosense Webster. Dr Prabhu has received a NHMRC Post-Doctoral Research Fellowship; and received consulting fees, fellowship support, and educational grants from Biosense Webster, Abbott Medical, and Boston Scientific. Dr Ling has received grants from Abbott Australia. Dr Sterns has received personal fees from Biosense Webster. Dr Ginks has served on the Speakers Bureau for Biosense Webster; and as a speaker for Abbott. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2024 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Sex-specific outcomes after catheter ablation (CA) for atrial fibrillation (AF) have reported conflicting findings., Objective: We examined the impact of female sex on outcomes in patients with persistent AF (PsAF) from the Catheter Ablation for Persistent Atrial Fibrillation: A Multicentre Randomized Trial of Pulmonary Vein Isolation vs PVI with Posterior Left Atrial Wall Isolation (CAPLA) randomized trial., Methods: A total of 338 patients with PsAF were randomized to pulmonary vein isolation (PVI) or PVI with posterior wall isolation (PWI). The primary outcome was arrhythmia recurrence at 12 months. Clinical and electroanatomical characteristics, arrhythmia recurrence, and quality of life were compared between women and men., Results: Seventy-nine women (23.4%; PVI 37; PVI + PWI 42) and 259 men (76.6%; PVI 131; PVI + PWI 128) underwent AF ablation. Women were older {median age 70.4 (interquartile range [IQR] 64.8-74.6) years vs 64.0 (IQR 56.7-69.7) years; P < .001} and had more advanced left atrial electroanatomical remodeling. At 12 months, arrhythmia-free survival was lower in women (44.3% vs 56.8% in men; hazard ratio 1.44; 95% confidence interval 1.02-2.04; log-rank, P = .036). PWI did not improve arrhythmia-free survival at 12 months (hazard ratio 1.02; 95% confidence interval 0.74-1.40; log-rank, P = .711). The median AF burden was 0% in both groups (women: IQR 0.0%-2.2% vs men: IQR 0.0%-2.8%; P = .804). Health care utilization was comparable between women (36.7%) and men (30.1%) (P = .241); however, women were more likely to undergo a repeat procedure (17.7% vs 6.9%; P = .007). Women reported more severe baseline anxiety (average Hospital Anxiety and Depression Scale [HADS] anxiety score 7.5 ± 4.9 vs 6.3 ± 4.3 in men; P = .035) and AF-related symptoms (baseline Atrial Fibrillation Effect on Quality-of-Life Questionnaire [AFEQT] score 46.7 ± 20.7 vs 55.9 ± 23.0 in men; P = .002), with comparable improvements in psychological symptoms (change in HADS anxiety score -3.8 ± 4.6 vs -3.0 ± 4.5; P = .152 (change in HADS depression score -2.9 ± 5.0 vs -2.6 ± 4.0; P = .542) and greater improvement in AFEQT score compared with men at 12 months (change in AFEQT score +45.9 ± 23.1 vs +39.2 ± 24.8; P = .048)., Conclusion: Women undergoing CA for PsAF report more significant symptoms and poorer quality of life at baseline than men. Despite higher arrhythmia recurrence and repeat procedures in women, the AF burden was comparably low, resulting in significant improvements in quality of life and psychological well-being after CA in both sexes., Competing Interests: Disclosures The following industry funding sources regarding activities outside the submitted work have been declared in accordance with the ICMJE guidelines. Dr Segan has received a combined National Heart Foundation/National Health and Medical Research Council (NHMRC) PhD scholarship. Dr Kistler is a recipient of the investigator grant from the NHMRC and has received funding from Abbott Medical for consultancy and speaking engagements and has served on the advisory board with fellowship support from Biosense Webster. Dr Kalman has received fellowship support from Medtronic and Biosense Webster. Dr Sanders has served on the advisory board of Medtronic, Abbott Medical, Boston Scientific, CathRx, and PaceMate and has received funding for research and consultancy from Medtronic, Abbott Medical, Boston Scientific, and MicroPort. Dr Lee has received consulting fees from Biosense Webster. Dr Sterns has received consulting fees from Biosense Webster. Dr Ginks has received funding for speaking engagements from Abbott and Biosense Webster. Dr Prabhu has received fellowship and training support from the National Heart Foundation, Abbott Medical, and Boston Scientific. He has also received speaker fees and advisory fees from Abbott Medical and Biosense Webster. The remaining authors have nothing to disclose., (Copyright © 2024 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Importance: Catheter ablation for patients with atrial fibrillation (AF) and heart failure with reduced ejection fraction (HFrEF) is associated with improved left ventricular ejection fraction (LVEF) and survival compared with medical therapy. Nonrandomized studies have reported improved success with posterior wall isolation (PWI)., Objective: To determine the impact of pulmonary vein isolation (PVI) with PWI vs PVI alone on outcomes in patients with HFrEF., Design, Setting, and Participants: This was an ad hoc secondary analysis of the CAPLA trial, a multicenter, prospective, randomized control trial that involved 11 centers in 3 countries (Australia, Canada, and UK). CAPLA featured 338 patients with persistent AF randomized to either PVI plusPWI or PVI alone. This substudy included patients in the original CAPLA study who had symptomatic HFrEF (LVEF <50% and New York Heart Association class ≥II)., Interventions: Pulmonary vein isolation with PWI vs PVI alone., Main Outcomes and Measures: The primary end point was freedom from any documented atrial arrhythmia greater than 30 seconds, after a single ablation procedure, without the use of antiarrhythmic drug (AAD) therapy at 12 months., Results: A total of 98 patients with persistent AF and symptomatic HFrEF were identified (mean [SD] age, 62.1 [9.8] years; 79.5% men; and mean [SD] LVEF at baseline, 34.6% [7.9%]). After 12 months, 58.7% of patients with PVI plus PWI were free from recurrent atrial arrhythmia without the use of AAD therapy vs 61.5% with PVI alone (hazard ratio, 1.02; 95% CI, 0.54-1.91; P = .96). There were no significant differences in freedom from atrial arrhythmia with or without AAD therapy after multiple procedures (PVI plus PWI vs PVI alone, 60.9% vs 65.4%; P = .73) or AF burden (median, 0% in both groups; P = .78). Mean LVEF improved substantially in PVI plus PWI (∆ LVEF, 19.3% [13.0%; P < .01) and PVI alone (18.2% [14.1%; P < .01), with no difference between groups (P = .71). Normalization of LV function occurred in 65.2% of patients in the PVI plus PWI group and 50.0% of patients with PVI alone (P = .13)., Conclusions and Relevance: The results of this study indicate that addition of PWI to PVI did not improve freedom from arrhythmia recurrence or recovery of LVEF in patients with persistent AF and symptomatic HFrEF. Catheter ablation was associated with significant improvements in systolic function, irrespective of ablation strategy used. These results caution against the routine inclusion of PWI in patients with HFrEF undergoing first-time catheter ablation for persistent AF., Trial Registration: http://anzctr.org.au Identifier: ACTRN12616001436460.

Background: Pulmonary vein isolation (PVI) is less effective in patients with persistent atrial fibrillation (PsAF). Adjunctive ablation targeting low voltage areas (LVAs) may improve arrhythmia outcomes., Objectives: This study aims to compare the outcomes of adding posterior wall isolation (PWI) to PVI, vs PVI alone in PsAF patients with posterior wall LVAs., Methods: The CAPLA (Effect of Catheter Ablation Using Pulmonary Vein Isolation With vs Without Posterior Left Atrial Wall Isolation on Atrial Arrhythmia Recurrence in Patients With Persistent Atrial Fibrillation) study was a multicenter, randomized trial involving PsAF patients randomized 1:1 to either PVI alone or PVI with PWI. Voltage mapping performed during pacing pre-ablation was reviewed offline, with LVA defined as bipolar voltage of <0.5 mV. The primary endpoint was freedom from any documented atrial arrhythmia of >30 seconds off antiarrhythmic medication at 12 months after a single ablation procedure in patients with posterior LVA., Results: A total of 210 patients (average 64.6 ± 9.2 years,73.3% males, median atrial fibrillation duration 4.5 months [IQR: 2 to 8 months]) underwent multipolar left atrial mapping during coronary sinus pacing with posterior LVA present in 69 (32.9%). Patients with posterior LVA were more likely to have LVA in other atrial regions (91.7% vs 57.1%; P < 0.01), larger left atrial diameter (4.8 cm vs 4.4 cm; P < 0.01), and significantly increased risk of atrial arrhythmia recurrence at 12 months (LVA: 56.5% vs no LVA: 41.4%; HR: 1.51; 95% CI: 1.01-2.27; P = 0.04) compared to no posterior LVA. However, the addition of PWI to PVI did not significantly improve freedom from atrial arrhythmia recurrence over PVI alone (PVI with PWI: 44.8% vs PVI: 41.9%; HR: 0.95; 95% CI: 0.51-1.79; P = 0.95)., Conclusions: In patients with PsAF undergoing catheter ablation, posterior LVA was associated with a significant increase in atrial arrhythmia recurrence. However, the addition of PWI in those with posterior LVA did not reduce atrial arrhythmia recurrence over PVI alone., Competing Interests: Funding and Author Disclosures This study received seed grant funding from the Baker department of Cardiometabolic Health, University of Melbourne. Dr Lee has received consulting fees from Biosense Webster. Dr Sanders has served on advisory boards for Medtronic, Abbott Medical, Boston Scientific, CathRx, and PaceMate; and has received funding for research and consultancy from Medtronic, Abbott Medical, Boston Scientific, and Microport. Dr Kalman has received fellowship support from Medtronic and Biosense Webster. Dr Kistler has received the investigator grant from the NHMRC; has received funding from Abbott Medical for consultancy and speaking engagements; and has served on the advisory board with fellowship support from Biosense Webster. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2023 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Catheter ablation is an effective strategy in atrial fibrillation (AF). However, its timing in the course of management remains unclear. The aim of this study was to determine if an early vs. delayed AF ablation strategy is associated with differences in arrhythmia outcomes during 12-month follow-up., Methods and Results: One hundred patients with symptomatic AF referred to a tertiary centre for management were randomized in a 1:1 ratio to either an early ablation strategy (within 1 month of recruitment) or a delayed ablation strategy (optimized medical therapy followed by catheter ablation at 12 months post recruitment). The primary endpoint was atrial arrhythmia free survival at 12 months post-ablation. Secondary outcomes included: (i) AF burden, (ii) AF burden by AF phenotype, and (iii) antiarrhythmic drug (AAD) use at 12 months. Overall, 89 patients completed the study protocol (Early vs. Delayed: 48 vs. 41). Mean age was 59 ± 12.9 years (29% women). Pulmonary vein isolation was achieved in 100% of patients. At 12 months, 56.3% of patients in the early ablation group were free from recurrent arrhythmia, compared with 58.6% in the delayed ablation group (HR 1.12, 95% CI 0.59-2.13, P = 0.7). All secondary outcomes showed no significant difference including median AF burden (Early vs. Delayed: 0% [IQR 3.2] vs. 0% [5], P = 0.66), median AF burden amongst paroxysmal AF patients (0% [IQR 1.1] vs. 0% [4.5], P = 0.78), or persistent AF patients (0% [IQR 22.8] vs. 0% [5.6], P = 0.45) or AAD use (33% vs. 37%, P = 0.8)., Conclusion: Compared with an early ablation strategy, delaying AF ablation by 12 months for AAD management did not result in reduced ablation efficacy., Competing Interests: Conflict of interest All authors declare no conflict of interest for this contribution., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: Patients with heart failure with preserved ejection fraction (HFpEF) frequently develop atrial fibrillation (AF). There are no randomized trials examining the effects of AF ablation on HFpEF outcomes., Objectives: The aim of this study is to compare the effects of AF ablation vs usual medical therapy on markers of HFpEF severity, including exercise hemodynamics, natriuretic peptide levels, and patient symptoms., Methods: Patients with concomitant AF and HFpEF underwent exercise right heart catheterization and cardiopulmonary exercise testing. HFpEF was confirmed with pulmonary capillary wedge pressure (PCWP) of 15 mm Hg at rest or ≥25 mm Hg on exercise. Patients were randomized to AF ablation vs medical therapy, with investigations repeated at 6 months. The primary outcome was change in peak exercise PCWP on follow-up., Results: A total of 31 patients (mean age: 66.1 years; 51.6% females, 80.6% persistent AF) were randomized to AF ablation (n = 16) vs medical therapy (n = 15). Baseline characteristics were comparable across both groups. At 6 months, ablation reduced the primary outcome of peak PCWP from baseline (30.4 ± 4.2 to 25.4 ± 4.5 mm Hg; P < 0.01). Improvements were also seen in peak relative VO 2 (20.2 ± 5.9 to 23.1 ± 7.2 mL/kg/min; P < 0.01), N-terminal pro-B-type natriuretic peptide levels (794 ± 698 to 141 ± 60 ng/L; P = 0.04), and MLHF (Minnesota Living with Heart Failure) score (51 ± -21.9 to 16.6 ± 17.5; P < 0.01). No differences were detected in the medical arm. Following ablation, 50% no longer met exercise right heart catheterization-based criteria for HFpEF vs 7% in the medical arm (P = 0.02)., Conclusions: AF ablation improves invasive exercise hemodynamic parameters, exercise capacity, and quality of life in patients with concomitant AF and HFpEF., Competing Interests: Funding Support and Author Disclosures Dr Chieng is supported by co-funded NHMRC/NHF post-graduate scholarship. Dr Prabhu has received an NHMRC Post-Doctoral Research Fellowship. Dr Voskoboinik has received a National Heart Foundation Early Career Fellowship. Dr Lee has received consulting fees from Biosense Webster. Dr Kistler has received funding from Abbott Medical for consultancy and speaking engagements; and has served on the advisory board with fellowship support from Biosense Webster. Dr Kalman has received fellowship support from Medtronic and Biosense Webster. Dr Kaye has received an NHMRC Investigator Grant. Dr Ling has received funding from Abbott Medical for project funding, consultancy, and speaking engagements; and has received funding from Abbott Medical for project funding, consultancy, and speaking engagements. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2023 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

The well-defined concept of aberrant ventricular conduction was introduced over 100 years ago and, despite advances in cardiac physiology and electrophysiologic testing, it is still widely misunderstood. Aberrant ventricular conduction is due to physiologic refractoriness of the His-Purkinje system and in most cases does not reflect underlying conduction system disease. Electrophysiologically, aberrant ventricular conduction can manifest with premature atrial ectopics, the Ashman phenomenon with atrial tachyarrhythmias, concealed conduction, echo beats and with the sinus mechanism including rate dependent bundle branch block, bradycardia dependent bundle branch block and early sinus beats. It is important to recognise aberrant ventricular conduction in the context of a broad complex tachycardia, as the differentiation between supraventricular tachyarrhythmias with aberrant ventricular conduction and ventricular tachyarrhythmias carry different therapeutic and prognostic implications. This review will define the ECG footprints of aberrant ventricular conduction to allow accurate ECG interpretation., Competing Interests: Conflicts of Interest None., (Crown Copyright © 2023. Published by Elsevier B.V. All rights reserved.)

Importance: Pulmonary vein isolation (PVI) alone is less effective in patients with persistent atrial fibrillation (AF) compared with paroxysmal AF. The left atrial posterior wall may contribute to maintenance of persistent AF, and posterior wall isolation (PWI) is a common PVI adjunct. However, PWI has not been subjected to randomized comparison., Objective: To compare PVI with PWI vs PVI alone in patients with persistent AF undergoing first-time catheter ablation., Design, Setting, and Participants: Investigator initiated, multicenter, randomized clinical trial involving 11 centers in 3 countries (Australia, Canada, UK). Symptomatic patients with persistent AF were randomized 1:1 to either PVI with PWI or PVI alone. Patients were enrolled July 2018-March 2021, with 1-year follow-up completed March 2022., Interventions: The PVI with PWI group (n = 170) underwent wide antral pulmonary vein isolation followed by posterior wall isolation involving linear ablation at the roof and floor to achieve electrical isolation. The PVI-alone group (n = 168) underwent wide antral pulmonary vein isolation alone., Main Outcomes and Measures: Primary end point was freedom from any documented atrial arrhythmia of more than 30 seconds without antiarrhythmic medication at 12 months, after a single ablation procedure. The 23 secondary outcomes included freedom from atrial arrhythmia with/without antiarrhythmic medication after multiple procedures, freedom from symptomatic AF with/without antiarrhythmic medication after multiple procedures, AF burden between study groups at 12 months, procedural outcomes, and complications., Results: Among 338 patients randomized (median age, 65.6 [IQR, 13.1] years; 76.9% men), 330 (97.6%) completed the study. After 12 months, 89 patients (52.4%) assigned to PVI with PWI were free from recurrent atrial arrhythmia without antiarrhythmic medication after a single procedure, compared with 90 (53.6%) assigned to PVI alone (between-group difference, -1.2%; hazard ratio [HR], 0.99 [95% CI, 0.73-1.36]; P = .98). Of the secondary end points, 9 showed no significant difference, including freedom from atrial arrhythmia with/without antiarrhythmic medication after multiple procedures (58.2% for PVI with PWI vs 60.1% for PVI alone; HR, 1.10 [95% CI, 0.79-1.55]; P = .57), freedom from symptomatic AF with/without antiarrhythmic medication after multiple procedures (68.2% vs 72%; HR, 1.20 [95% CI, 0.80-1.78]; P = .36) or AF burden (0% [IQR, 0%-2.3%] vs 0% [IQR, 0%-2.8%], P = .47). Mean procedural times (142 [SD, 69] vs 121 [SD, 57] minutes, P < .001) and ablation times (34 [SD, 21] vs 28 [SD, 12] minutes, P < .001) were significantly shorter for PVI alone. There were 6 complications for PVI with PWI and 4 for PVI alone., Conclusions and Relevance: In patients undergoing first-time catheter ablation for persistent AF, the addition of PWI to PVI alone did not significantly improve freedom from atrial arrhythmia at 12 months compared with PVI alone. These findings do not support the empirical inclusion of PWI for ablation of persistent AF., Trial Registration: anzctr.org.au Identifier: ACTRN12616001436460.

Background: Observational studies report that obstructive sleep apnea (OSA) is associated with an increasingly remodeled atrial substrate in atrial fibrillation (AF). However, the impact of OSA management on the electrophysiologic substrate has not been evaluated., Objectives: In this study, the authors sought to determine the impact of OSA management on the atrial substrate in AF., Methods: We recruited 24 consecutive patients referred for AF management with at least moderate OSA (apnea-hypopnea index [AHI] ≥15). Participants were randomized in a 1:1 ratio to commence continuous positive airway pressure (CPAP) or no therapy (n = 12 CPAP; n = 12 no CPAP). All participants underwent invasive electrophysiologic study (high-density right atrial mapping) at baseline and after a minimum of 6 months. Outcome variables were atrial voltage (mV), conduction velocity (m/s), atrial surface area <0.5 mV (%), proportion of complex points (%), and atrial effective refractory periods (ms). Change between groups over time was compared., Results: Clinical characteristics and electrophysiologic parameters were similar between groups at baseline. Compliance with CPAP therapy was high (device usage: 79% ± 19%; mean usage/day: 268 ± 91 min) and resulted in significant AHI reduction (mean reduction: 31 ± 23 events/h). There were no differences in blood pressure or body mass index between groups over time. At follow-up, the CPAP group had faster conduction velocity (0.86 ± 0.16 m/s vs 0.69 ± 0.12 m/s; P (time × group) = 0.034), significantly higher voltages (2.30 ± 0.57 mV vs 1.94 ± 0.72 mV; P < 0.05), and lower proportion of complex points (8.87% ± 3.61% vs 11.93% ± 4.94%; P = 0.011) compared with the control group. CPAP therapy also resulted in a trend toward lower proportion of atrial surface area <0.5 mV (1.04% ± 1.41% vs 4.80% ± 5.12%; P = 0.065)., Conclusions: CPAP therapy results in reversal of atrial remodeling in AF and provides mechanistic evidence advocating for management of OSA in AF., Competing Interests: Funding Support and Author Disclosures For this work, Dr Nalliah received the Eric Prystowsky Fellows Clinical Research Award, Heart Rhythm Society, May 2020, and the Ralph Reader Young Investigator Prize of the Cardiac Society of Australia and New Zealand, December 2020; and he is supported also by the National Heart Foundation and a Viertel Charitable Foundation Clinical Investigator Award. Dr Voskoboinik is supported by an NHMRC EL1 Investigator Grant and an NHF Early Career Fellowship. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2022 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: The success of pulmonary vein isolation (PVI) is reduced in persistent AF (PsAF) compared to paroxysmal AF. Adjunctive ablation strategies have failed to show consistent incremental benefit over PVI alone in randomized studies. The left atrial posterior wall is a potential source of non-PV triggers and atrial substrate which may promote the initiation and maintenance of PsAF. Adding posterior wall isolation (PWI) to PVI had shown conflicting outcomes, with earlier studies confounded by methodological limitations., Objectives: To determine whether combining PWI with PVI significantly improves freedom from AF recurrence, compared to PVI alone, in patients with PsAF., Methods: This is a multi-center, prospective, international randomized clinical trial. 338 patients with symptomatic PsAF refractory to anti-arrhythmic therapy (AAD) will be randomized to either PVI alone or PVI with PWI in a 1:1 ratio. PVI involves wide antral circumferential pulmonary vein (PV) isolation, utilizing contact force sensing ablation catheters. PWI involves the creation of a floor line connecting the inferior aspect of the PVs, and a roof line connecting the superior aspect of the PVs. Follow up is for a minimum of 12 months with rhythm monitoring via implantable cardiac device and/or loop monitor, or frequent intermittent monitoring with an ECG device. The primary outcome is freedom from any documented atrial arrhythmia of > 30 seconds off AAD at 12 months, after a single ablation procedure., Conclusions: This randomized study aims to determine the success and safety of adjunctive PWI to PVI in patients with persistent AF., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Aims: Obstructive sleep apnoea (OSA) associates with atrial fibrillation (AF), but the relationship of OSA severity and AF phenotype with the atrial substrate remains poorly defined. We sought to define the atrial substrate across the spectrum of OSA severity utilizing high-density mapping., Methods and Results: Sixty-six consecutive patients (male 71%, age 61 ± 9) having AF ablation (paroxysmal AF 36, persistent AF 30) were recruited. All patents underwent formal overnight polysomnography and high-density left atrial (LA) mapping (mean 2351 ± 1244 points) in paced rhythm. Apnoea-hypopnoea index (AHI) (mean 21 ± 18) associated with lower voltage (-0.34, P = 0.005), increased complex points (r = 0.43, P < 0.001), more low-voltage areas (r = 0.42, P < 0.001), and greater voltage heterogeneity (r = 0.39, P = 0.001), and persisted after multivariable adjustment. Atrial conduction heterogeneity (r = 0.24, P = 0.025) but not conduction velocity (r = -0.09, P = 0.50) associated with AHI. Patchy regions of low voltage that co-localized with slowed conduction defined the atrial substrate in paroxysmal AF, while a diffuse atrial substrate predominated in persistent AF. The association of AHI with remodelling was most apparent among paroxysmal AF [LA voltage: paroxysmal AF -0.015 (-0.025, -0.005), P = 0.004 vs. persistent AF -0.006 (-0.017, 0.005), P = 0.30]. Furthermore, in paroxysmal AF an AHI ≥ 30 defined a threshold at which atrial remodelling became most evident (nil-mild vs. moderate vs. severe: 1.92 ± 0.42 mV vs. 1.84 ± 0.28 mV vs. 1.34 ± 0.41 mV, P = 0.006). In contrast, significant remodelling was observed across all OSA categories in persistent AF (1.67 ± 0.55 mV vs. 1.50 ± 0.66 mV vs. 1.55 ± 0.67 mV, P = 0.82)., Conclusion: High-density mapping observed that OSA associates with marked atrial remodelling, predominantly among paroxysmal AF cohorts with severe OSA. This may facilitate the identification of AF patients that stand to derive the greatest benefit from OSA management., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2021. For permissions, please email: journals.permissions@oup.com.)

Aims: Prior studies have described a variety of mechanisms for atrial fibrillation (AF) originating in the right atrium (RA). In this study, we report a series of patients in whom an extensive right atrial free wall low-voltage zone (LVZ) served as the AF substrate., Methods and Results: Five patients with a clinical syndrome of paroxysmal AF and atrial tachycardia (AT) underwent electrophysiologic evaluation. Five patients (3 M; age 52 ± 7 years) had symptomatic paroxysmal AF for (28 ± 17 months) not responsive to medical therapy. At the initial EP study, AT was inducible in four patients and was spontaneous in one patient. In all patients, tachycardia instability precluded detailed AT mapping. Sinus or pace maps indicated an extensive LVZ in the lateral RA trabeculated free wall which consisted of regions of low amplitude complex signals interspersed between electrically silent areas. Radiofrequency ablation aimed at rendering the LVZ electrical inert was successful in eliminating AF in four of five patients. At a follow-up of 28 ± 15 months, one patient had an isolated recurrence of AF. However, two patients required repeat ablation for recurrent AT., Conclusion: An extensive LVZ in the trabeculated RA free wall constitutes an unusual substrate for AF. These patients also demonstrate unstable ATs originating from the same zone. Radiofrequency ablation to render the low-voltage zone electrically inert is an effective strategy to manage AF and AT., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2020. For permissions, please email: journals.permissions@oup.com.)

Background: Female gender is associated with an increased recurrence of atrial fibrillation (AF) after catheter ablation (CA). Although AF is more common in men, women constitute a significant proportion with persistent atrial fibrillation (PsAF)., Objective: The purpose of this study was to determine whether multiple ablation procedures improves arrhythmia outcomes in females with PsAF compared to men., Methods: We performed a multicenter observational study to determine long-term arrhythmia outcomes in patients undergoing >1 CA for PsAF. CA involved pulmonary vein (PV) isolation with additional ablation including linear, posterior wall isolation, electrogram-guided, or a combination of these., Results: A total of 281 patients had >1 ablation procedure for PsAF and were included in this analysis (mean age 58.7 ± 9.3 years; 86 [30.6%] female; left atrial [LA] area 27.0 ± 5.3 cm 2 ; PsAF duration 1.7 ± 1.7 years). At mean follow-up of 45.5 ± 31.8 months, freedom from recurrent AF was present in 148 patients(52.7%) after 2.2 ± 0.5 procedures. After multivariate analysis, female gender (hazard ratio [HR] 2.10; P <.001) and enduring PV isolation (HR 1.64; P = .01) were independently associated with AF recurrence. Enduring PV isolation was significantly higher in women than in men (33.7% vs 19.5%; P = .01)., Conclusion: Female gender was independently and strongly associated with arrhythmia recurrence in patients undergoing multiple procedures for PsAF. PV reconnection was less likely, and fewer reconnected PVs occurred in women. Further studies are required to better understand the mechanisms responsible for AF in females to assist in closing the gender gap in the success of CA., (Copyright © 2019 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Objectives: This study sought to determine the impact of rate and direction on left atrial (LA) substrate., Background: The extent to which substrate mapped in sinus rhythm varies according to cycle length and direction of wave front propagation is unknown., Methods: A total of 73 consecutive patients with atrial fibrillation (AF) underwent electroanatomic LA mapping before pulmonary vein isolation using multipolar catheter during distal coronary sinus (CS) pacing at 600 ms and 300 ms. Additional maps were created during left superior pulmonary vein pacing at 300 ms. Bipolar voltage, conduction velocity (CV), and complex signals were determined., Results: Mean age was 61 ± 9 years, 67% were men, and 53% had persistent AF. Global mean voltage was lower with CS pacing at 300 ms compared with 600 ms (1.56 ± 0.47 mV vs. 1.74 ± 0.48 mV; p < 0.001). This was seen in all LA segments. Global CV was reduced (30.4 ± 13.0 cm/s vs. 38.6 ± 14.0 cm/s; p < 0.001) with greater complex signals at 300 ms (8.9% vs. 5.3%; p < 0.005). Compared with CS pacing, left superior pulmonary vein pacing demonstrated highly regional changes with decreased voltage (1.04 ± 0.43 mV vs. 1.47 ± 0.53 mV; p = 0.01) and CV (24.4 ± 13.0 cm/s vs. 39.9 ± 16.6 cm/s; p = 0.008), and greater complex signals posteriorly. Longer AF duration in paroxysmal AF (p = 0.02) and shorter duration in persistent AF (p = 0.015) and left ventricular ejection fraction (p = 0.016) were independent predictors of voltage change., Conclusions: In patients with AF, variation in cycle length and direction of wave front activation produce both generalized and regional changes in voltage, CV, and complex fractionation, resulting in significant changes in substrate maps. This study highlights the potential limitations of static low-voltage maps to identify the AF ablation target zone., (Copyright © 2019. Published by Elsevier Inc.)

Background: The key drivers of symptom severity and health-related quality of life (hr-QOL) in patients with atrial fibrillation (AF) remain unclear. We aimed to determine the relative contribution to symptom severity and hr-QOL of clinical factors including left ventricular (LV) diastolic function and ventricular rate control during AF and of psychological functioning., Methods: Seventy-eight consecutive patients with symptomatic AF and preserved LV systolic function underwent detailed evaluation of i) AF symptom severity and hr-QOL; ii) clinical factors including left ventricular (LV) diastolic function, AF burden, and ventricular rate during AF and iii) state and trait aspects of psychological functioning., Results: Moderate-to-severe AF-related symptoms were reported by 64% of the study population whilst 36% reported no more than mild symptoms. Worse symptom severity was associated with a higher score on the Perceived Stress Scale (16.7 ± 4.4 vs. 5.4 ± 4.4, p < 0.0001) and higher prevalence of the Type D Personality (20/50 vs. 4/28, p = 0.012). In multivariable models, only a predisposition to subjectively appraise life situations as stressful (higher PSS score) and a personality with a higher degree of negative affectivity and social inhibition (higher TDPS score) were independent predictors of higher AF symptom severity and poorer hr-QOL. No clinical factors including AF burden, ventricular rates during AF or LV diastolic function were significant predictors of AF-specific symptoms or hr-QOL., Conclusion: In a tertiary AF population with preserved LV systolic function, only psychological functioning consistently predicts both AF-related symptoms and hr-QOL. LV diastolic function, AF burden, and ventricular rate during AF are not independent predictors., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Background An association between atrial fibrillation ( AF ), anxiety, and depression is recognized, but the spectrum of psychological distress remains unclear. We aimed to characterize the severity and predictors of distress associated with AF in a tertiary population and its response to AF management. Methods and Results Seventy-eight patients with symptomatic AF underwent evaluation, including of AF symptom severity, health-related quality of life, psychological distress, suicidal ideation, and specific personality traits. Twenty participants underwent AF ablation and 58 were managed medically, with repeat assessments at 4, 8, and 12 months. Severe distress (Hospital Anxiety and Depression Scale score, ≥15/42) was identified in 27 of 78 (35%). Independent predictors were a personality marked by vulnerability to stress (Perceived Stress Scale: R 2 , 0.54; β=0.7±0.1; t=7.8; P<0.001) and 1 marked by negativity/social inhibition (Type D Personality Scale: R 2 , 0.47; β=0.7±0.1; t=6.7; P<0.001). Suicidal ideation was reported by 16 of 78 (20%) and was predicted by personality traits (Perceived Stress Scale score: R 2 , 0.35; odds ratio, 1.22±0.06; P<0.001; Type D Personality Scale score: R 2 , 0.48; odds ratio, 1.43±0.14; P<0.001). Effective AF ablation (median AF burden 1% [0-1%] over 12 months) was associated with significant reductions in distress (Hospital Anxiety and Depression Scale score, 13.9±1.8 to 4.3±1.8; P<0.05) and prevalence of suicidal ideation (30-5%; P=0.02). Conclusions There was a high prevalence of severe psychological distress (35%) and of suicidal ideation (20%) in a tertiary AF population, with personality traits predicting both. Effective AF ablation was associated with significant improvements, suggesting AF itself may be a treatable causative factor of distress.

Background: Despite technological advances, studies continue to report high complication rates for atrial fibrillation (AF) ablation. We sought to review complication rates for AF ablation at a high-volume centre over a 14-year period and identify predictors of complications., Methods: We reviewed prospectively collected data from 2750 consecutive AF ablation procedures at our institution using radiofrequency energy (RF) between January 2004 and May 2017. All cases were performed under general anaesthetic with transoesophageal echocardiography (TEE), 3D-mapping and an irrigated ablation catheter. Double transseptal puncture was performed under TEE guidance. All patients underwent wide antral circumferential isolation of the pulmonary veins (30W anteriorly, 25W posteriorly) with substrate modification at operator discretion., Results: Of 2255 initial and 495 redo procedures, ablation strategies were: pulmonary vein isolation (PVI) only 2097 (76.3%), PVI+ LA lines 368 (13.4%), PVI+posterior wall 191 (6.9%), PVI+cavotricuspid isthmus 277 (10.1%). There were 23 major (0.84%) and 20 minor (0.73%) complications. Cardiac tamponade (five cases - 0.18%) and phrenic nerve palsy (one case - 0.04%) rates were very low. Major vascular complications necessitating surgery or blood transfusion occurred in five patients (0.18%). There were no cases of death, permanent disability, atrio-oesophageal fistulae or symptomatic pulmonary vein (PV) stenosis, although there were five TEE probe-related complications (0.18%). Female gender (OR 2.14; 95% CI 1.07-4.26) but not age >70 (OR 1.01) was the only multivariate predictor of complications., Conclusions: Atrial fibrillation ablation performed at a high-volume centre using RF can be achieved with a low major complication rate in a representative AF population over a sustained period of time., (Copyright © 2018 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.)

Aims: Catheter ablation to achieve posterior left atrial wall (PW) isolation may be performed as an adjunct to pulmonary vein isolation (PVI) in patients with persistent atrial fibrillation (AF). We aimed to determine whether routine adenosine challenge for dormant posterior wall conduction improved long-term outcome., Methods and Results: A total of 161 patients with persistent AF (mean age 59 ± 9 years, AF duration 6 ± 5 years) underwent catheter ablation involving circumferential PVI followed by PW isolation. Posterior left atrial wall isolation was performed with a roof and inferior wall line with the endpoint of bidirectional block. In 54 patients, adenosine 15 mg was sequentially administered to assess reconnection of the pulmonary veins and PW. Sites of transient reconnection were ablated and adenosine was repeated until no further reconnection was present. Holter monitoring was performed at 6 and 12 months to assess for arrhythmia recurrence. Posterior left atrial wall isolation was successfully achieved in 91% of 161 patients (procedure duration 191 ± 49 min, mean RF time 40 ± 19 min). Adenosine-induced reconnection of the PW was demonstrated in 17%. The single procedure freedom from recurrent atrial arrhythmia was superior in the adenosine challenge group (65%) vs. no adenosine challenge (40%, P < 0.01) at a mean follow-up of 19 ± 8 months. After multiple procedures, there was significantly improved freedom from AF between patients with vs. without adenosine PW challenge (85 vs. 65%, P = 0.01)., Conclusion: Posterior left atrial wall isolation in addition to PVI is a readily achievable ablation strategy in patients with persistent AF. Routine adenosine challenge for dormant posterior wall conduction was associated with an improvement in the success of catheter ablation for persistent AF., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions please email: journals.permissions@oup.com.)

Background: With the recent advent of high-density (HD) 3-dimensional (3D) mapping, the utility of entrainment is uncertain. However, the limitations of visual representation and interpretation of these high-resolution 3D maps are unclear., Objective: The purpose of this study was to determine the strengths and limitations of both HD 3D mapping and entrainment mapping during mapping of right atrial macroreentry., Methods: Fifteen patients were studied. The number and type of circuits accounting for ≥90% of the tachycardia cycle length using HD 3D mapping were verified using systematic entrainment mapping. Entrainment sites with an unexpectedly long postpacing interval despite proximity to the active circuit were evaluated., Results: Based on HD 3D mapping, 27 circuits were observed: 12 peritricuspid, 2 upper loop reentry, 10 lower loop reentry, and 3 lateral wall circuits. With entrainment, 17 of the 27 circuits were active: all 12 peritricuspid and 2 upper loop reentry. However, lower loop reentry was confirmed in only 3 of 10, and none of the 3 lateral wall circuits were present. Mean percentage of tachycardia cycle length covered by active circuits was 98% ± 1% vs 97% ± 2% for passive circuits (P = .09). None of the 345 entrainment runs terminated tachycardia or changed tachycardia mechanism. In 8 of 15 patients, 13 examples of unexpectedly long postpacing interval were observed at entrainment sites located distal to localized zones of slow conduction seen on HD 3D mapping., Conclusion: Using HD 3D mapping, "visual reentry" may be due to passive circuitous propagation rather than a critical reentrant circuit. HD 3D mapping provides new insights into regional conduction and helps explain unusual entrainment phenomena., (Copyright © 2017 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Pulmonary vein isolation (PVI) is a well-established treatment of atrial fibrillation (AF), with contact force (CF)-sensing catheters joining 3-dimensional mapping systems and image integration as technological advancements over the last decade., Objective: The purpose of this study was to analyze trends in radiation exposure for AF ablation over the last 12 years at our center., Methods: We reviewed prospectively collected data of 2344 consecutive PVI procedures for either paroxysmal or persistent AF between January 2004 and December 2015. During this period, all cases used 3-dimensional mapping systems, with 8 software and 2 hardware upgrades. Primary endpoints were fluoroscopy time, absorbed dose (Air Kerma in mGy), and effective dose (mSv)., Results: In total, 1914 patients underwent initial PVI, and 430 patients underwent redo PVI using radiofrequency energy. Fluoroscopy time, and absorbed and effective doses significantly and progressively decreased over the 12-year period for initial PVI as follows: 2004-2006: 61 ± 27 minutes; 2007-2009: 46 ± 14 minutes, 1365 ± 1369 mGy, 11.3 ± 12.5 mSv; 2010-2012: 31 ± 11, 464 ± 339 mGy, 9.0 ± 10.4 mSv; and 2013-2015: 17 ± 9 minutes, 304 ± 758 mGy, 5.5 ± 6.7 mSv. CF-sensing catheters were used for 357/508 PVI only cases between 2014 and 2015. Fluoroscopy times (11 ± 5 vs 21 ± 8 minutes; P <.001) and absorbed dose (200 ± 524 vs 470 ± 1326 mGy; P = .004) were significantly shorter with this catheter., Conclusion: Radiation exposure has dramatically decreased over the last decade for PVI and is related to operator experience, annual case volume, technology evolution, and more recently CF-sensing catheters. This has significant implications for both patient and operator long-term risk., (Copyright © 2017 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Advanced atrial remodeling predicts poor clinical outcomes in human atrial fibrillation (AF)., Objective: The purpose of this study was to define the magnitude and predictors of change in left atrial (LA) structural remodeling over 12 months of AF., Methods: Thirty-eight patients with paroxysmal AF managed medically (group 1), 20 undergoing AF ablation (group 2), and 25 control patients with no AF history (group 3) prospectively underwent echocardiographic assessment of strain variables of LA reservoir function at baseline and at 4, 8, and 12 months. In addition, P-wave duration (Pmax,, Pmean) and dispersion (Pdis) were measured. AF burden was quantified by implanted recorders. Twenty patients undergoing ablation underwent electroanatomic mapping (mean 333 ± 40 points) for correlation with LA strain., Result: Group 1 demonstrated significant deterioration in total LA strain (26.3% ± 1.2% to 21.7% ± 1.2%, P < .05) and increases in Pmax (132 ± 3 ms to 138 ± 3 ms, P < .05) and Pdis (37 ± 2 ms to 42 ± 2 ms, P < .05). AF burden ≥10% was specifically associated with decline in strain and with P-wave prolongation. Conversely, group 2 manifest improvement in total LA strain (21.3% ± 1.7% to 28.6% ± 1.7%, P <.05) and reductions in Pmax (136 ± 4 ms to 119 ± 4 ms, P < .05) and Pdis (47 ± 3 ms to 32 ± 3 ms, P < .05). Change was not significant in group 3. LA mean voltage (r = 0.71, P = .0005), percent low voltage electrograms (r = -0.59, P = .006), percent complex electrograms (r = -0.68, P = .0009), and LA activation time (r = -0.69, P = .001) correlated with total strain as a measure of LA reservoir function., Conclusion: High-burden AF is associated with progressive LA structural remodeling. In contrast, AF ablation results in significant reverse remodeling. These data may have implications for timing of ablative intervention., (Copyright © 2016. Published by Elsevier Inc.)

Aims: Pulmonary vein isolation (PVI) is the cornerstone of catheter ablation of atrial fibrillation (AF). The intervenous ridge (IVR) may be incorporated into ablation strategies to achieve PVI; however, randomized trials are lacking. We performed a randomized multi-centre international study to compare the outcomes of (i) circumferential antral PVI (CPVI) alone (minimal) vs. (ii) CPVI with IVR ablation to achieve individual PVI (maximal)., Methods and Results: Two hundred and thirty-four patients with paroxysmal AF underwent CPVI and were randomized to a minimal or maximal ablation strategy. The primary outcome of recurrent atrial arrhythmia was assessed with 7-day Holter monitoring at 6 and 12 months. PVI was achieved in all patients. Radiofrequency ablation time was longer in the maximal group (46.6 ± 14.6 vs. 41.5 ± 13.1 min; P < 0.01), with no significant differences in procedural or fluoroscopy times. At mean follow-up of 17 ± 8 months, there was no difference in freedom from AF after a single procedure between a minimal (70%) and maximal ablation strategy (62%; P = 0.25). In the minimal group, ablation was required on the IVR to achieve electrical isolation in 44%, and was associated with a significant reduction in freedom from AF (57%) compared with the minimal group without IVR ablation (80%; P < 0.01)., Conclusion: There was no statistically significant difference in freedom from AF between a minimal and maximal ablation strategy. Despite attempts to achieve PVI with antral ablation, IVR ablation is commonly required. Patients in whom antral isolation can be achieved without IVR ablation have higher long-term freedom from AF (the Minimax study; ACTRN12610000863033)., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.)

Background: Gender-based differences in the clinical nature of cardiac arrhythmias such as atrial fibrillation (AF) are well established., Objective: The purpose of this study was to identify any such gender-based differences in the underlying pulmonary vein and atrial substrate., Methods and Results: Thirty-eight patients with no history of AF undergoing catheter ablation for supraventricular tachycardia (SVT) and 55 with paroxysmal or persistent AF undergoing catheter ablation of AF underwent detailed electroanatomic mapping of the pulmonary veins and atria. Refractory periods in multiple locations, sinus node function, endocardial bipolar voltage, pulmonary vein and atrial conduction, and bipolar electrogram complexity were analyzed. There were no significant between-gender differences in age or other clinical variables known to impact on the atrial or pulmonary vein substrate. In neither the AF nor the non-AF cohorts were there any significant differences in atrial or pulmonary vein refractoriness, sinus node function, any measure of PV electrophysiology, or any measure of atrial electrophysiology., Conclusion: No systematic between-gender differences were observed in the PV or atrial substrate either in those with or without a history of AF, with a similar prevalence of the cardiovascular comorbidities frequently associated with atrial remodeling and AF seen in both male and female groups., (© 2014 Wiley Periodicals, Inc.)

Background: There is a complex interplay between the atria and ventricles in atrial fibrillation (AF). Cardiac magnetic resonance (CMR) imaging provides detailed tissue characterization, identifying focal ventricular fibrosis with late gadolinium enhancement (ventricular late gadolinium enhancement) and diffuse fibrosis with postcontrast-enhanced T1 mapping. The aim of the present study was to investigate the relationship between postcontrast ventricular T1 relaxation time on CMR and freedom from AF after pulmonary vein isolation., Methods and Results: One hundred three patients undergoing catheter ablation for symptomatic AF (66% paroxysmal AF; age, 58±10 years; left atrial area, 27±7 cm(2)) underwent preprocedure CMR to determine postcontrast ventricular T1 time. Follow-up included clinical review and 7-day Holter monitors at 6 monthly intervals. All patients underwent successful pulmonary vein isolation. At a mean follow-up of 15±7 months, the single procedure success was 74%. Postcontrast ventricular T1 time was significantly shorter in patients with recurrent AF (366±73 ms) versus patients without AF recurrence (428±90 ms; P=0.002). Univariate predictors of AF recurrence included postcontrast ventricular T1 time, AF type (paroxysmal versus persistent), AF duration, and body mass index. After multivariate analysis, ventricular T1 time (P=0.03) and AF duration (P=0.03) were the only independent predictors. Freedom from AF was present in 84% of patients with a postcontrast ventricular T1 time >380 ms versus 56% in patients with a postcontrast ventricular T1 time <380 ms (P=0.002)., Conclusions: A shorter postcontrast ventricular T1 relaxation time on CMR is associated with reduced freedom from AF after catheter ablation. Diffuse ventricular fibrosis as demonstrated by CMR may, in part, explain recurrent AF after AF ablation., (© 2014 American Heart Association, Inc.)

Background: The impact of diffuse atrial fibrosis detected by T1 mapping on the clinical outcome after atrial fibrillation (AF) ablation is unknown., Objective: This study aimed to validate and assess the impact of post-contrast cardiac magnetic resonance (CMR) imaging atrial T1 mapping on the clinical outcome after catheter ablation for AF., Methods: CMR imaging was performed in 3 groups by using a clinical 1.5-T scanner: controls, patients with paroxysmal AF, and patients with persistent AF. A T1 mapping sequence was used to calculate the post-contrast T1 relaxation time (T1 time) at the interatrial septum as an index of diffuse atrial fibrosis. A subset underwent left atrial endocardial bipolar voltage mapping for electrophysiologic correlation. After AF ablation, patients underwent clinical review and 7-day Holter monitoring at 6-month intervals., Results: One hundred thirty-two patients (20 controls, 71 (63%) patients with paroxysmal AF, and 41 (37%) patients with persistent AF) underwent CMR imaging. Post-contrast atrial T1 time was significantly shorter in AF groups (237 ± 42 ms) than in controls (280 ± 37 ms) (P < .001). Post-contrast atrial T1 time correlated with mean septal voltage (R2 = .48; P < .001) and global left atrial voltage (R(2) = .41; P < .001). A diagnosis of AF, AF duration, and left ventricular end-diastolic volume independently predicted shortened post-contrast atrial T1 time. The single procedure success rate was 74% at 12 ± 5 months postablation. Post-contrast atrial T1 time was the only predictor of arrhythmia recurrence in multivariate analysis (P = .015). A post-contrast atrial T1 time of >230 ms was associated with freedom from AF in 85% relative to 62% with a post-contrast atrial T1 time of <230 ms (P = .01)., Conclusion: Post-contrast atrial T1 time as measured using CMR imaging provides an index of atrial fibrosis that correlates with tissue voltage, presence of AF, and clinical outcomes after catheter ablation., (Copyright © 2014 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Circumferential pulmonary vein (PV) isolation is the cornerstone of catheter ablation for atrial fibrillation (AF); however, PV reconnection remains problematic., Objective: To assess the impact of PV anatomy on outcome after AF ablation., Methods: One hundred two patients with paroxysmal AF underwent cardiac magnetic resonance (60%) or computed tomography (40%) before AF ablation. PV anatomy was classified according to the presence of common PVs, accessory PVs, PV branching pattern, and the dimensions of the PV ostia, intervenous ridges (IVRs), and the left PV-left atrial appendage ridge., Results: Four discrete PVs were present in 48(47%) of the patients: a left common PV in 38(37%), a right common PV in 2(2%), an accessory right PV in 20(20%), and left PV in 4(4%). At a mean follow-up of 12 ± 4 months, 75 of 102 (74%) patients were free of recurrent AF. A LCPV was associated with an increase in freedom from AF (87% vs 66% for 4 PV anatomy; P = .03). Greater left IVR length (16.9 ± 3.5 mm vs 14.0 ± 3.0 mm; P ≤ .001) and width (1.4 ± 0.6 mm vs 1.1 ± 0.6 mm; P = .02) were associated with increased AF recurrence. After multivariate analysis, abnormal anatomy (LCPV or accessory PV) and left IVR length were found to be the only independent predictors of freedom from AF., Conclusions: Four discrete PVs are present in the minority of patients with paroxysmal AF undergoing PV isolation. The presence of a LCPV is associated with an increased freedom from AF after catheter ablation. PV anatomy may in part explain the variable outcome to electrical isolation in patients with paroxysmal AF., (Copyright © 2014 Heart Rhythm Society. All rights reserved.)

Background/objective: The purpose of this study was to characterize the association between the extent of left atrial electroanatomic remodeling in atrial fibrillation and the atrial fibrillation cycle length derived from lead V₁ of the surface ECG (V1AFCL)., Methods: Twenty-three patients in atrial fibrillation (AF) who presented for AF ablation underwent detailed electroanatomic mapping of the left atrium. The digital 12-lead ECG was exported for offline analysis, with signal filtering and QRST subtraction used to reveal the fibrillatory baseline in lead V₁. Mean V1AFCL was determined by direct annotation of the fibrillatory baseline, and the corresponding dominant V1AFCL was determined by Fourier transformation to derive the dominant frequency from the frequency power spectrum. The simultaneous AFCL from proximal and distal coronary sinus recordings was determined using the same methods. The strength of the association between various left atrial remodeling variables and V1AFCL was determined., Results: The 2 methods of deriving V1AFCL and intracardiac AFCL were found to produce highly equivalent results. V1AFCL showed significant correlation with intracardiac AFCL derived from both proximal and distal coronary sinus recordings. A longer V1AFCL was associated with slower left atrial conduction velocity and greater signal complexity but not with other remodeling variables, including left atrial size, atrial refractoriness, and mean endocardial voltage., Conclusion: A longer atrial fibrillatory cycle length in surface ECG lead V1 is significantly associated with parameters of more advanced left atrial electroanatomic remodeling, specifically slower atrial conduction and more extensive electrogram fractionation., (Copyright © 2014 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Introduction: Electrogram (EGM) characteristics are used to infer catheter-tissue contact. We examined if (a) atrial EGM characteristics predicted CF and (b) compared the value of CF versus other surrogates for predicting lesion efficacy., Methods and Results: Twelve paroxysmal AF patients underwent pulmonary vein isolation using radiofrequency (RF) ablation facilitated by a novel CF-sensing catheter. Operators were blinded to CF. EGM amplitude, width, and morphology were measured pre- and post-RF. At each RF site, average CF, force-time integral (FTI), impedance fall, time to impedance plateau, maximum power, catheter tip temperature, and total energy delivered were recorded. An effective lesion was defined based on previously validated EGM criteria for transmural lesions. There was a moderate correlation between CF and EGM amplitude (r = 0.19) and EGM width (r = -0.22). Pre-RF, EGM amplitude, and width had modest to poor discriminative capacity for identifying preablation CF (e.g., EGM amplitude identified CF>20 g with sensitivity and specificity of 67% and 60%, respectively). Preablation CF, FTI, and total energy delivered during RF were the only independent predictors of effective lesion formation. Neither pre-RF EGM amplitude/width nor power, temperature, and impedance changes during RF predicted effective lesion formation. An average CF >16 g or FTI >404 g*s had excellent sensitivity and specificity (>80%) for identifying an effective lesion., Conclusions: EGM characteristics do not reliably predict either CF before the onset of RF, nor do they predict the likelihood of an effective lesion. CF parameters were superior to power, temperature, and impedance changes during RF in predicting lesion efficacy., (© 2013 Wiley Periodicals, Inc.)

Objectives: To characterize the nature of atrial fibrillation (AF) activation in human persistent AF (PerAF) using modern tools including activation, directionality analyses, complex-fractionated electrogram, and spectral information., Background: The mechanism of PerAF in humans is uncertain., Methods and Results: High-density epicardial mapping (128 electrodes/6.75 cm(2)) of the posterior LA wall (PLAW), LA and RA appendage (LAA, RAA), and RSPV-LA junction was performed in 18 patients with PerAF undergoing open heart surgery. Continuous 10 s recordings were analysed offline. Activation patterns were characterized into four subtypes (i) wavefronts (broad or multiple), (ii) rotational circuits (≥2 rotations of 360°), (iii) focal sources with centrifugal activation of the entire mapping area, or (iv) disorganized activity [isolated chaotic activation(s) that propagate ≤3 bipoles or activation(s) that occur as isolated beats dissociated from the activation of adjacent bipole sites]. Activation at a total of 36 regions were analysed (14 PLAW, 3 RSPV-LA, 12 LAA, and 7 RAA) creating a database of 2904 activation patterns. In the majority of maps, activation patterns were highly heterogeneous with multiple unstable activation patterns transitioning from one to another during each recording. A mean of 3.8 ± 1.6 activation subtypes was seen per map. The most common patterns seen were multiple wavefronts (56.2 ± 32%) and disorganized activity (24.2 ± 30.3%). Only 2 of 36 maps (5.5%) showed a single stable activation pattern throughout the 10-s period. These were stable planar wavefronts. Three transient rotational circuits were observed. Two of the transient circuits were located in the posterior left atrium, while the third was located on the anterior surface of the LAA. Focal activations accounted for 11.3 ± 14.2% of activations and were all short-lived (≤2 beats), with no site demonstrating sustained focal activity., Conclusion: Human long-lasting PerAF is characterized by heterogeneous and unstable patterns of activation including wavefronts, transient rotational circuits, and disorganized activity.

Aims: Percutaneous coronary intervention (PCI) and catheter ablation are well-accepted therapeutic interventions for treatment of coronary artery disease and atrial fibrillation (AF), respectively. We sought to examine temporal trends in the provision of these services over the past decade in Australia., Methods and Results: A retrospective review of the numbers of PCIs and AF ablations from 2000/01 to 2009/10 was performed on data from three sources: the Australian Institute of Health, Welfare and Aging (AIHW), Medicare Australia database (MA), and local records at a high volume tertiary referral centre (RMH) for AF ablation. Linear regression models were fitted comparing trends in population-adjusted procedural numbers over the 10-year period. There was a 5% per year population-adjusted increment in PCIs over 10 years from both the AIHW and MA sources, respectively (P < 0.001). This was similar to the growth rate of all cardiovascular procedures (AIHW: 5.1 vs. 3.8%/year, P = 0.27). Atrial fibrillation ablations showed a 30.9, 23.2, and 39.8% per year population-adjusted increment over 10 years from the AIHW, MA, and RMH sources respectively (P < 0.001 for all). Growth of AF ablations was significantly higher than PCIs (P < 0.001 for AIHW and MA sources) and all cardiovascular procedures (AIHW: 30.9 vs. 3.8%/year, P < 0.001)., Conclusion: The provision of catheter-based AF ablation services in Australia has increased exponentially over the past decade. Its annual growth rate exceeded that of PCIs and all cardiovascular procedures. Given the increasing epidemic of AF, these data have critical implications for public health policy assessing the adequacy of infrastructure, training, and funding for AF ablation services.

Introduction: Pulmonary vein reconnection is a major limitation of pulmonary vein isolation (PVI) for symptomatic atrial fibrillation (AF). Adenosine may unmask dormant PV conduction and facilitate consolidation of PV isolation. We performed a systematic review of the literature to determine the impact of routine adenosine administration on clinical outcomes in patients undergoing PVI., Methods: References and electronic databases reporting AF ablation and adenosine following PVI were searched through to 31 July 2012. Six studies included 544 patients to assess the impact of catheter ablation to target adenosine-induced PV reconnection on AF ablation outcome and 3 studies included 612 patients to assess the impact of adenosine testing on AF ablation outcome. Relative risks were calculated and combined in a meta-analysis using random effects modeling., Results: Routine adenosine testing for PV reconnection with additional targeted ablation resulted in a significant increase in freedom from AF post-PVI (RR 1.25; 95% CI 1.12-1.40; P < 0.001). However, within the group of patients undergoing adenosine testing, those with reconnection identified a population with a trend to reduction in freedom from AF despite the use of further targeted ablation in the reconnection group (RR 0.91 with 95% CI 0.81-1.03; P = 0.15)., Conclusion: Routine adenosine testing is associated with an improvement in freedom from AF post-PVI. Paradoxically acute adenosine-induced PV reconnection may portend a greater likelihood of AF recurrence despite additional ablation. Randomized controlled trials are required to determine the role of adenosine testing post-PVI., (© 2013 Wiley Periodicals, Inc.)

Background: Catheter-tissue contact force (CF) determines radiofrequency (RF) ablation lesion size. Impedance changes during RF delivery are used as surrogate markers for CF. The relationship between impedance and real-time CF in humans remains unknown., Objectives: To determine whether impedance changes have predictive value for real-time CF during catheter ablation of atrial arrhythmias., Methods: Real-time CF, force-time integral, and impedance were measured in 2265 RF lesions for atrial fibrillation or flutter in 34 patients. Operators were blinded to CF measurements. Impedance preablation, at 5-second intervals for 30 seconds after the RF onset, maximal impedance fall and time to impedance plateau during RF were correlated with CF. Average CF was divided into low (≤20 g), intermediate (21-60 g), and high (>60 g) categories., Results: Preablation impedance poorly correlated with preablation CF (R = .07). Maximal impedance fall modestly correlated with average CF and force-time integral (R = .32 and .37, respectively). There was a large degree of overlap in impedance fall between different CF categories. A maximal impedance fall of 10 Ω could predict average CF of >20 g, with a sensitivity and specificity of 71% and 53% and a positive and negative predictive value of 51% and 49%, respectively. Impedance fall was only able to differentiate between different CF categories ≥15 seconds after the RF onset. Higher CFs moderately correlated with delayed plateau in impedance (R = .41)., Conclusions: Impedance measurements (both baseline and impedance fall) are, at best, moderately efficacious as surrogate markers for predicting real-time catheter-tissue CF. These findings highlight the importance of real-time CF measurements, rather than impedance changes to optimize ablation efficacy., (Crown Copyright © 2013. Published by Elsevier Inc. All rights reserved.)

Background: Catheter-tissue contact is critical for effective lesion creation. We characterized the contact force (CF) at different anatomic sites during antral pulmonary vein (PV) isolation for atrial fibrillation., Methods and Results: Two experienced operators performed PV isolation in 22 patients facilitated by a novel CF-sensing ablation catheter in a blinded fashion. Average CF and force-time integral data from 1602 lesions were analyzed. The left and right PV antra were divided into the following: carina, superior, inferior, anterior, and posterior quadrants for analysis. There was significant variability in CF within and between different PV quadrants (P<0.05). Lowest CF of all left PV sites was at the carina and anterior quadrant, whereas highest CF was at the superior and inferior quadrants (P<0.05). Lowest CF of all right PV sites was at the carina, whereas highest CF was at the anterior and inferior quadrants (P<0.05). When comparing similar PV quadrants on the left versus right (eg, left carina versus right carina), CF was always higher in the right PVs (P<0.05), except at the superior quadrant where CF was similar in the left and right PVs (P=0.19). There was no specific pattern of anatomic distribution of excess CF (P=0.39)., Conclusions: Monitoring of catheter-tissue CF during PV isolation demonstrates significant variability in CF within and between different PV antral sites. Sites of lowest CF were the carina and anterior left PVs and the carina of the right PVs. This information may be important for improving ablation efficacy and clinical outcomes during PV isolation.

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in human beating hearts. AF initiates self-perpetuating changes in electrophysiology, structure and functional properties of the atria, a phenomenon known as atrial remodeling. Hypertension, heart failure, valvular heart disease, sleep apnea, congenital heart disease are well known risk factors for AF that contribute to the development of atrial substrate. There is some evidence that reversal of atrial remodeling is possible with correction of antecedent conditions, however the timing of the intervention or upstream therapy may be critical. This review will describe the pathophysiology of atrial remodeling as it pertains to AF. We will describe components of remodeling including changes in atrial refractoriness, conduction and atrial structure, in addition to autonomic changes and anatomic factors that predispose to remodeling. We will discuss our current understanding of the electrophysiological changes that contribute to AF persistence. We will describe nature of atrial and pulmonary vein remodeling in the context of different forms of AF, with and without predisposing risk factors. We will describe the nature of remodeling over time following therapeutic interventions such as AF ablation in order to show that it does not necessarily improve and may worsen., (Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.)

Introduction: Atrial fibrillation (AF) and atrial flutter (AFL) are related arrhythmias with common triggers, yet in individual patients either AF or AFL often predominates. We performed detailed electrophysiologic (EP) and electroanatomic (EA) studies of the right atrium (RA) in patients with AF and AFL to determine substrate differences that may explain the preferential expression of AF/AFL in individual patients., Methods: Patients with AF (n = 13) were compared to patients with persistent AFL (n = 10). Detailed studies were performed, and 3-dimensional electroanatomic mapping studies were created and the RA was divided into 4 segments for regional analysis. Global, septal, lateral, anterior, and posterior segments were compared for analysis of: bipolar voltage; proportion of low-voltage areas and areas of electrical silence; conduction times; and proportion of abnormal signals (fractionated signals and double potentials)., Results: Compared to patients with AF, patients with AFL had (1) lower bipolar voltage and an increase in the proportion of low-voltage areas; (2) an increase in the proportion of complex signals; and (3) prolongation of activation times., Conclusions: Patients with AFL showed more advanced remodeling than patients with AF with slowed conduction, lower voltage areas with regions of electrical silence, and a greater proportion of complex signals, particularly in the posterior RA. These changes facilitate the stabilization of AFL and may explain why some patients are more likely to develop AFL as a sustained clinical arrhythmia., (© 2012 Wiley Periodicals, Inc.)

Background: Esophageal hematoma recently has been reported as a form of esophageal injury after atrial fibrillation (AF) ablation, attributed to the use of transesophageal echocardiography (TEE). We sought to determine the incidence, clinical features, and sequelae of this form of esophageal injury., Methods and Results: This was a prospective series of 1110 AF ablation procedures performed under general anesthesia (GA) over 9 years. TEE was inserted after induction of GA to exclude left atrial appendage thrombus, define cardiac function, and guide transseptal puncture. The procedural incidence of esophageal hematoma was 0.27% (3/1110 procedures, mortality 0%). Odonyphagia, regurgitation, and hoarseness were the predominant symptoms, with an onset within 12 hours. There was absence of fever and neurological symptoms. Chest computed tomography excluded atrio-esophageal fistula and was diagnostic of esophageal hematoma localized to either the upper esophagus or extending the length of the mid and lower esophagus; endoscopy confirmed the diagnosis. Management was conservative in all cases comprising of ceasing oral intake and anticoagulation. Long term sequelae included esophageal stricture formation requiring dilatation, persistent esophageal dysmotility (mid esophageal hematoma), and vocal cord paralysis, resulting in hoarse voice (upper esophageal hematoma)., Conclusions: Esophageal hematoma is a rare but important differential diagnosis for esophageal injury after TEE-guided AF ablation under GA, and can result in significant patient morbidity. Key clinical features differentiate presentation of esophageal hematoma from that of an atrio-esophageal fistula.

Background: Whether curative ablation can prevent progression of the atrial electroanatomic remodeling associated with atrial fibrillation (AF) is not known., Objective: The purpose of this study was to determine whether successful radiofrequency ablation (RFA) of AF can prevent progression of the atrial substrate associated with AF., Methods: Detailed right atrial electroanatomic maps from 11 patients without apparent structural heart disease undergoing RFA of AF at baseline and ≥6 months following successful RFA were compared to 11 control patients undergoing electrophysiologic evaluation of supraventricular tachycardia. Bipolar voltage, conduction, effective refractory periods (ERPs), and signal complexity were assessed., Results: At baseline compared with the control group, the AF group demonstrated (1) lower voltage (P <.001); (2) slowed conduction (P = .005); (3) more prevalent complex signals (P <.001); (4) prolonged regional refractoriness (P <.05), and (5) left atrial dilation (P = .01). At 10 ± 13 month follow-up, the AF group demonstrated the following compared to baseline: (1) lower voltage (P <.05); (2) either no improvement or further slowing of conduction; (3) further prolongation of regional refractoriness (P <.05); and (4) reversal of left atrial dilation (P <.05)., Conclusion: Patients with lone AF demonstrate evidence of an abnormal atrial substrate at baseline compared to control patients without AF. This substrate does not appear to reverse even after successful catheter ablation. These findings may have implications for long-term outcomes of ablation and for timing of ablative intervention., (Copyright © 2012 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Persistent atrial fibrillation (AF) is associated with a high risk of recurrence after electrical cardioversion., Objective: We examined if long-term supplementation with omega-3 polyunsaturated fatty acids in fish oils commenced >1 month prior to electrical cardioversion and continued thereafter reduces recurrence of persistent AF., Methods: This was an open-label, randomized study of 178 patients with persistent AF >1-month duration. Participants were assigned to control group (n = 87) or omega-3 group (6 g/d fish oil; n = 91) and underwent cardioversion 1 month later. Concurrent antiarrhythmic use of sotalol or amiodarone was permitted. Fish oil was continued till return of persistent AF or a maximum of 1 year. Intention-to-treat analysis was performed for the primary end point defined as the recurrence of persistent AF., Results: Mean duration of fish oil intake was 56 days precardioversion and a total of 242 days in follow-up. Eicosapentaenoic acid and docosahexaenoic acid, the active components of fish oils, were 1.8-fold and 2.1-fold higher, respectively, in the omega-3 group compared with controls at the time of cardioversion (P <.001). At 90 days, 38.5% of the patients receiving omega-3 fatty acid supplement had AF recurrence compared with 77.5% of the controls (hazard ratio [omega-3 vs control] 0.38; 95% confidence interval 0.27-0.56; P <.001). Omega-3 intake was associated with a significant reduction in AF recurrence with or without concurrent antiarrhythmic drugs., Conclusions: Omega-3 polyunsaturated fatty acid supplementation commenced >1 month prior to electrical cardioversion and continued thereafter reduces the recurrence of persistent AF. Randomized controlled trials on long-term fish oil supplementation are needed to confirm these findings., (Copyright © 2012 Heart Rhythm Society. All rights reserved.)

Introduction: The nature of the atrial substrate thought to contribute toward maintaining atrial fibrillation (AF) outside the pulmonary veins remains poorly defined. Therefore, our objective was to determine whether patients with paroxysmal and persistent AF have an abnormal electroanatomic substrate within the left atrium (LA)., Methods and Results: Thirty-one patients with AF (17 paroxysmal AF and 14 persistent AF) were compared with 15 age-matched controls with left-sided supraventricular tachycardia (SVT). High-density 3-dimensional electroanatomic maps were created and the LA was divided into 8 segments for regional analysis. Bipolar voltage, conduction, and effective refractory periods (ERPs) of the posterior LA, left atrial appendage (LAA), and distal coronary sinus (CSd) and percentage complex signals were assessed. In the majority of LA regions, compared with controls, AF patients had: (1) lower mean voltage and a higher percentage low voltage; (2) slower conduction; and (3) more prevalent complex signals. Many of these changes were more marked in the persistent than the paroxysmal AF group., Conclusions: Patients with AF have lower regional voltage, increased proportion of low voltage, slowed conduction, and increased proportion of complex signals compared to controls. Many of these changes are more pronounced in persistent AF patients, suggesting there may be a progressive nature to the changes. Differences occurred in the absence of structural heart disease. These substrate abnormalities provide further insight into the progressive nature of atrial remodeling and the mechanisms involved in maintenance of AF., (© 2011 Wiley Periodicals, Inc.)

Background: The pulmonary veins (PVs) and the PV-LA (left atrium) junction are established sources of triggers initiating atrial fibrillation. In addition, they have been implicated in the maintenance of arrhythmia., Objective: To undertake high-density electrophysiological characterization of the right superior PV-LA junction in humans., Methods: Mapping was performed in 18 patients without a history of atrial fibrillation undergoing cardiac surgery. A high-density epicardial plaque was positioned at the anterior right superior pulmonary vein covering 3 regions: LA, PV-LA junction, and the PV. Isochronal maps were created during (1) sinus rhythm (SR); (2) LA pacing (LA-Pace); (3) PV pacing (PV-Pace); (4) LA programmed electrical stimulation (LA-PES); and (5) PV programmed electrical stimulation (PV-PES). Regional differences in conduction slowing/conduction block (CS/CB) and the prevalence of fractionated signals (FS) and double potentials (DPs) were assessed., Results: A region of isochronal crowding representing CS/CB developed at the PV-LA junction in 84% of the maps. Three distinct activation patterns were seen. Pattern 1: Uniform SR activation without CS/CB. LA-Pace and PES caused 1 to 2 lines of isochronal crowding (CS/CB) at the PV-LA junction. Pattern 2: CS/CB occurred at the PV-LA junction in SR. LA/PV-Pace and LA/PV-PES caused an increase in CS/CB at the PV-LA junction with widely split DPs and FS. Pattern 3: A single incomplete line of CS at the PV-LA junction in SR. With LA/PV pacing and LA/PV-PES, multiple lines (≥3) of CS/CB developed at the PV-LA junction with evidence of circuitous activation and a marked increase in DPs and FS., Conclusion: High-density epicardial mapping of the right superior pulmonary vein demonstrates marked functional conduction delay and circuitous activation patterns at the PV-LA junction, creating the substrate for reentry., (Copyright © 2012 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Aims: Mapping of atrial fibrillation (AF) involves identification of low-voltage regions associated with complex fractionated electrograms (CFE) which theoretically represent abnormal substrate and targets for ablation. Whether low-voltage CFE areas also identify abnormal substrate during paced rhythm is unknown., Methods and Results: Twelve patients with persistent AF undergoing ablation of AF had high-density three-dimensional electroanatomic maps created during AF and paced rhythm (24 maps) and the mean voltage during AF and paced rhythm was compared for eight segments of the left atrium (LA). The following were correlated during AF and paced rhythm: regional mean voltage; %low voltage (defined as <0.5 mV); and extent of CFE. In addition, the relationship between the extent of CFE in AF: (i) %low voltage and (ii) conduction during paced rhythm were determined. Mean voltage was lower during AF than paced rhythm for all regions and globally (0.7 ± 0.2 mV vs. 2.1 ± 0.6 mV, P < 0.001). The regional and overall %low voltage of the LA was greater during AF than paced rhythm (53 ± 19% vs. 9 ± 2%, P < 0.001). There was no correlation between mean voltage or %low voltage during AF and paced rhythm. Complex fractionated electrograms were prevalent throughout all regions during AF, but did not correlate with %low voltage, fractionation, or slowed conduction during paced rhythm., Conclusion: Areas of CFE and low voltage recorded during AF frequently demonstrate normal atrial myocardial characteristics (normal conduction, electrograms, and voltage) during sinus rhythm. Therefore, AF CFE sites do not necessarily identify regions of an abnormal atrial substrate. However, this does not exclude the possibility that CFE might identify a focal driver or source occurring in a region of normal atrial myocardium.

Background: Complex fractionated atrial electrograms (CFAEs) and regions of high dominant frequency (DF) both may identify sites critical to the maintenance of atrial fibrillation (AF). CFAEs may be defined by either (1) complex multicomponent electrograms (EGMs) and/or continuous electrical activity (multicomponent/continuous EGM) or (2) discrete high-frequency EGMs., Objective: The purpose of this study was to test if the 2 definitions of CFAE identify the same arrhythmia substrate and determine the relationship of CFAE to areas of high DF., Methods: High-density epicardial mapping of the posterior left atrium was performed in 10 patients with long-lasting persistent AF. Point-by-point analysis was performed to determine the spatial distribution and correlation of CFAE defined as either (1) multicomponent/continuous-EGMs or (2) AF cycle length <120 ms. Additionally, spatial analysis was performed to determine the relationship of high DF sites to CFAE sites defined by each of the 2 definitions., Results: The percentage of sites deemed CFAE varied markedly between patients and was different depending on the definition of CFAE adopted. There was a poor correlation between CFAE defined by multicomponent/continuous EGMs and AF cycle length <120 ms (r = 0.18). High DF sites were arranged in clusters evenly distributed throughout the posterior left atrium, with 4.2 ± 1.0 high DF clusters per patient. Although there was poor point-by-point correlation between multicomponent/continuous EGMs and high DF sites (r = 0.107), spatial analysis revealed that 96% of multicomponent/continuous EGMs were found adjacent to and partially surrounding (≤5 mm) high DF sites., Conclusion: There is poor anatomic overlap between CFAE defined by multicomponent/continuous EGMs and CFAE defined by AF cycle length <120 ms. Multicomponent/continuous EGMs are found adjacent to and surrounding sites of high DF. Further studies are needed to determine the mechanisms responsible for these different signals., (Copyright © 2011 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Introduction: Rapid PV activity is critical in initiating and maintaining AF. The underlying substrate responsible for this remains uncertain. We sought to identify if patients with paroxysmal (PAF) and persistent atrial fibrillation (PeAF) have an abnormal substrate within the pulmonary veins (PVs)., Methods and Results: Thirty-nine patients with AF (21 PAF, 18 PeAF) were compared with 15 age-matched controls with left-sided accessory pathways (AVRT). High-density 3D electroanatomic maps of the PVs were created. PV voltage, conduction, PV muscle sleeve length, effective refractory periods (ERPs) of the PVs, posterior left atrium (PLA), left atrial appendage (LAA) and distal coronary sinus (CSd), and signal complexity were assessed. Compared with controls, the PVs of AF patients had (1) lower mean-voltage and a higher % low-voltage; (2) shorter PV muscle sleeves; (3) slower conduction; (4) shorter ERP; and (5) more prevalent complex signals. Compared with the PAF group, the PeAF group had (1) higher % low voltage; (2) slower conduction; and (3) more complex signals. In PAF patients, the PLA and LAA ERPs were longer than controls and the PV ERP was shorter than controls; in PeAF patients PLA and LAA ERPs were reduced, but to a lesser extent than in the PVs. AF induction occurred during PV ERP testing in both AF groups, but not controls., Conclusions: PAF and PeAF patients demonstrate electrical and electroanatomic remodeling of the PVs compared to control patients without prior AF. Some of these changes were more marked in PeAF. , (© 2011 Wiley Periodicals, Inc.)

Objectives: To report the major complication rate associated with pulmonary vein antral isolation (PVAI) in a consecutive series of 500 patients from a single center., Background: Catheter ablation for atrial fibrillation (AF) is an established procedure for refractory AF. However, the risk of major complications has been reported to range from 3.9% to 4.5% and continues to represent a cause for concern. We hypothesized that these studies may have overestimated the rate of major complications associated with PVAI in patients with a low prevalence of structural heart disease (SHD)., Methods: Data were prospectively collected from 500 consecutive AF ablation procedures on 424 patients (mean age 55 ± 11 years, 79% men, paroxysmal AF-80% and persistent AF-20%, CHADS₂ scores of 0, 1, 2, 3 present in 64%, 28%, 7%, 1%, respectively), performed between July 2006 and September 2009. All procedures were performed under general anesthesia with intraoperative transesophageal echo. PVAI was performed using a nonfluoroscopic mapping system with an endpoint of PV isolation. Adjunctive left atrial ablation was performed in 21% of patients only. Major complications were defined from a compilation of those reported in 5 prior studies reporting complications., Results: In 500 procedures, there were no instances of death, stroke/TIA, cardiac tamponade, atrioesophageal fistula, or PV stenosis. Major complications occurred in 4 procedures (0.8%): esophageal hematoma (TEE probe)--2; pharyngeal trauma--1; and retroperitoneal hematoma-1., Conclusions: AF ablation can be performed safely in young patients without structural heart disease with a low risk (<1%) of major complications when using a strategy of PVAI., (© 2010 Wiley Periodicals, Inc.)

Introduction: Pulmonary veins play an important role in triggering atrial fibrillation (AF). Pulmonary vein isolation (PVI) is an effective treatment for patients with paroxysmal AF. However, the late AF recurrence rate in long-term follow-up of circumferential PV antral isolation (PVAI) is not well documented. We sought to determine the time to recurrence of arrhythmia after PVAI, and long-term rates of sinus rhythm after circumferential PVAI., Methods: One hundred consecutive patients with a mean age of 54 ± 10 years, with paroxysmal AF who underwent PVAI procedure were analyzed. Isolation of pulmonary veins was based on an electrophysiological and anatomical approach, with a nonfluoroscopic navigation mapping system to guide antral PVI. Ablation endpoint was vein isolation confirmed with a circular mapping catheter at first and subsequent procedures. Clinical, ECG, and Holter follow-up was undertaken every 3 months in the first year postablation, every 6 months thereafter, with additional prolonged monitoring if symptoms were reported. Time to arrhythmia recurrence, and representing arrhythmias, were documented., Results: Isolation of all 4 veins was successful in 97% patients with 3.9 ± 0.3 veins isolated/patient. Follow-up after the last RF procedure was at a mean of 39 ± 10 months (range 21-66 months). After a single procedure, sinus rhythm was maintained at long-term follow-up in 49% patients without use of antiarrhythmic drugs (AADs). After repeat procedure, sinus rhythm was maintained in 57% patients without the use of AADs, and in 82% patients including patients with AADs. A total of 18 of 100 patients had 2 procedures and 4 of 100 patients had 3 procedures for recurrent AF/AT. Most (86%) AF/AT recurrences occurred ≤ 1 year after the first procedure. Mean time to recurrence was 6 ± 10 months. Kaplan-Meier analysis on antiarrhythmics showed AF free rate of 87% at 1 year and 80% at 4 years. There were no major complications., Conclusion: PVAI is an effective strategy for the prevention of AF in the majority of patients with PAF. Maintenance of SR requires repeat procedure or continuation of AADs in a significant proportion of patients. After maintenance of sinus rhythm 1-year post-PVAI, a minority of patients will subsequently develop late recurrence of AF., (© 2010 Wiley Periodicals, Inc.)

Background: Complex fractionated atrial electrograms (CFAEs) are often identified as targets for radiofrequency ablation in the coronary sinus (CS) of patients with atrial fibrillation (AF)., Objective: The purpose of this study was to determine whether similar features are present in a normal control population., Methods: Twenty-four patients with AF (12 paroxysmal, 12 persistent) were compared with 12 controls (undergoing radiofrequency ablation for supraventricular tachycardia) in whom at least 1 minute of AF was induced by rapid atrial pacing. Electrogram comparisons during sinus rhythm and AF were made offline. A random 10-second window of AF was used for analysis of fractionation and dominant frequency., Results: The three groups were age matched. CFAEs during AF were less prevalent in the control versus the AF groups (control = 30% +/- 28%, paroxysmal AF = 63% +/- 34%, persistent AF = 62% +/- 29%, P = .01). This difference was significant for the proximal to mid-CS only. Conduction velocity within the CS was slower in AF versus control patients (paroxysmal AF = 51 +/- 6 cm/s, persistent AF = 52 +/- 6 cm/s, control = 73 +/- 11 cm/s, P <.001). Minimum AF cycle length was shorter in the AF groups versus the control group (paroxysmal AF = 132 +/- 34 ms, persistent AF = 127 +/- 34 ms, control = 168 +/- 30 ms, P = .01). No differences in dominant frequency or prevalence of sinus rhythm CFAE was seen among the three groups., Conclusion: AF patients have a higher prevalence of CFAE and short cycle length activation within the proximal CS than control patients with nonclinical AF. CFAE are associated with slowed CS conduction in AF patients. No difference in the dominant frequency during AF was seen. CS CFAEs are common in a control population with induced AF and are unlikely to signify clinically important AF drivers in this setting., (Copyright 2010 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)