Impact of early vs. delayed atrial fibrillation catheter ablation on atrial arrhythmia recurrences.

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.

The impact of age on ablation outcomes in AF-mediated cardiomyopathy.

INTRODUCTION: The absence of ventricular scar in patients with atrial fibrillation (AF) and systolic heart failure (HF) predicts left ventricular (LV) recovery following AF ablation. It is unknown whether age impacts the degree of LV recovery, reverse remodeling, or AF recurrence following catheter ablation (CA) among this population. OBJECTIVES: To evaluate the impact of age on LV recovery and AF recurrence in a population with AF and systolic HF without fibrosis (termed AF-mediated cardiomyopathy) following CA. METHODS: Consecutive patients undergoing CA between 2013 and 2021 with LV ejection fraction (LVEF) < 45% and absence of cardiac magnetic resonance imaging (CMR) detected LV myocardial fibrosis were stratified by age (<65 vs. ≥65 years). Following CA, participants underwent remote rhythm monitoring for 12 months with repeat CMR for HF surveillance. RESULTS: The study population consisted of 70 patients (10% female, mean LVEF 33 ± 9%), stratified into younger (age < 65 years, 63%) and older (age ≥ 65 years, 37%) cohorts. Baseline comorbidities, LVEF (34 ± 9 vs. 33 ± 8 ≥65 years, p = .686), atrial and ventricular dimensions (left atrial volume index: 55 ± 21 vs. 56 ± 14 mL/m2 age ≥ 65, p = .834; indexed left ventricular end-diastolic volume: 108 ± 40 vs. 104 ± 28 mL/m2 age ≥ 65, p = .681), pharmacotherapy and ablation strategy (pulmonary vein isolation in all; posterior wall isolation in 27% vs. 19% age ≥ 65, p = .448; cavotricuspid isthmus in 9% vs. 11.5% age ≥ 65) were comparable (all p > .05) albeit a higher CHADS2 VASc score in the older cohort (2.7 ± 0.9 vs. 1.6 ± 0.6 age < 65, p < .001).   Freedom from AF was comparable (hazard ratio: 0.65, 95% confidence interval: 0.38-1.48, LogRank p = .283) as was AF burden [0% (interquartile range, IQR: 0.0-2.1) vs. age ≥ 65: [0% (IQR 0.0-1.7), p = .516], irrespective of age. There was a significant improvement in LV systolic function in both groups (ΔLVEF + 21 ± 14% vs. +21 ± 12% age ≥ 65, p = .913), with LV recovery in the vast majority (73% vs. 69%, respectively, p = .759) at 13 (IQR: 12-16) months. This was accompanied by comparable improvements in functional status (New York Heart Association class p = .851; 6-min walk distance 50 ± 61 vs. 93 ± 134 m in age ≥ 65, p = .066), biomarkers (ΔN-terminal-pro brain natriuretic peptide -139 ± 246 vs. -168 ± 181 age ≥ 65,p = .629) and HF symptoms (Short Form-36 survey Δphysical component summary p = .483/Δmental component summary, p = .841). CONCLUSION: In patients undergoing CA for AF with systolic HF in the absence of ventricular scar, comparable improvements in ventricular function, symptoms, and freedom from AF are achieved irrespective of age.

Atrial Fibrillation Catheter Ablation vs Medical Therapy and Psychological Distress: A Randomized Clinical Trial.

Importance: The impact of atrial fibrillation (AF) catheter ablation on mental health outcomes is not well understood. Objective: To determine whether AF catheter ablation is associated with greater improvements in markers of psychological distress compared with medical therapy alone. Design, Setting, and Participants: The Randomized Evaluation of the Impact of Catheter Ablation on Psychological Distress in Atrial Fibrillation (REMEDIAL) study was a randomized trial of symptomatic participants conducted in 2 AF centers in Australia between June 2018 and March 2021. Interventions: Participants were randomized to receive AF catheter ablation (n = 52) or medical therapy (n = 48). Main Outcomes and Measures: The primary outcome was Hospital Anxiety and Depression Scale (HADS) score at 12 months. Secondary outcomes included follow-up assessments of prevalence of severe psychological distress (HADS score >15), anxiety HADS score, depression HADS score, and Beck Depression Inventory-II (BDI-II) score. Arrhythmia recurrence and AF burden data were also analyzed. Results: A total of 100 participants were randomized (mean age, 59 [12] years; 31 [32%] women; 54% with paroxysmal AF). Successful pulmonary vein isolation was achieved in all participants in the ablation group. The combined HADS score was lower in the ablation group vs the medical group at 6 months (8.2 [5.4] vs 11.9 [7.2]; P = .006) and at 12 months (7.6 [5.3] vs 11.8 [8.6]; between-group difference, -4.17 [95% CI, -7.04 to -1.31]; P = .005). Similarly, the prevalence of severe psychological distress was lower in the ablation group vs the medical therapy group at 6 months (14.2% vs 34%; P = .02) and at 12 months (10.2% vs 31.9%; P = .01), as was the anxiety HADS score at 6 months (4.7 [3.2] vs 6.4 [3.9]; P = .02) and 12 months (4.5 [3.3] vs 6.6 [4.8]; P = .02); the depression HADS score at 3 months (3.7 [2.6] vs 5.2 [4.0]; P = .047), 6 months (3.4 [2.7] vs 5.5 [3.9]; P = .004), and 12 months (3.1 [2.6] vs 5.2 [3.9]; P = .004); and the BDI-II score at 6 months (7.2 [6.1] vs 11.5 [9.0]; P = .01) and 12 months (6.6 [7.2] vs 10.9 [8.2]; P = .01). The median (IQR) AF burden in the ablation group was lower than in the medical therapy group (0% [0%-3.22%] vs 15.5% [1.0%-45.9%]; P < .001). Conclusion and Relevance: In this trial of participants with symptomatic AF, improvement in psychological symptoms of anxiety and depression was observed with catheter ablation, but not medical therapy. Trial Registration: ANZCTR Identifier: ACTRN12618000062224.

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.

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.

Polymorphic Ventricular Tachycardia Storm After Coronary Artery Bypass Graft Surgery: A Form of 'Angry Purkinje Syndrome'.

BACKGROUND: Polymorphic ventricular tachycardia (PMVT) is a highly lethal arrhythmia which is commonly caused by acute myocardial ischaemia. PMVT mediated by short-coupled ventricular ectopy patients with ischaemic heart disease but in the absence of acute ischaemia may relate to transient peri-infarct Purkinje fibre irritability and has been termed 'Angry Purkinje Syndrome'. METHODS: We present a case series of three patients with PMVT storm 3-5 days following coronary artery bypass graft surgery (CABG). In all three cases, recurrent episodes of PMVT were initiated by monomorphic ventricular ectopy with a short coupling interval. Acute coronary ischaemia was excluded in all three patients with a coronary angiogram and graft study. Two out of three of the patients commenced oral quinidine sulphate with subsequent rapid suppression of arrhythmia. Implantable cardiac defibrillators were implanted in all three patients and revealed no recurrence of PMVT following hospital discharge. CONCLUSION: The Angry Purkinje Syndrome is a rare but important cause of ventricular tachycardia storm after CABG surgery and is mediated by short-coupled ventricular ectopy in the absence of acute myocardial ischaemia. This arrhythmia may be highly responsive to quinidine.

Catheter ablation for persistent atrial fibrillation: A multicenter randomized trial of pulmonary vein isolation (PVI) versus PVI with posterior left atrial wall isolation (PWI) - The CAPLA study.

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.

Extensive right atrial free wall low-voltage zone as the substrate for atrial fibrillation: successful ablation by scar homogenization.

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.

Sleep apnoea has a dose-dependent effect on atrial remodelling in paroxysmal but not persistent atrial fibrillation: a high-density mapping study.

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.

Multipolar mapping with the high-density grid catheter compared with conventional point-by-point mapping to guide catheter ablation for focal arrhythmias.

BACKGROUND: Multipolar catheters provide high-density mapping which may reduce the procedural duration and improve the success of catheter ablation (CA) for focal arrhythmias. The high-density grid (HDG) catheter is a 16 electrode mapping catheter with bipole recordings at orthogonal splines. The aim of this study is to compare the clinical and procedural features from a cohort who underwent CA for focal arrhythmias using multipolar mapping (MPM) with age and case-matched cohort using point-by-point (PbyP) mapping. METHODS: Consecutive patients undergoing CA for focal arrhythmias between October 2018 and January 2020 guided by MPM were compared with PbyP mapping with the ablation catheter over a similar period. Demographics, procedural features, and outcomes were compared. RESULTS: A total of 54 patients (27 in MPM vs. 27 in PbyP mapping) underwent CA for 68 focal arrhythmias (26 atrial and 42 ventricular). In the MPM group, the electrogram at the successful site was significantly earlier (39 ± 11 ms) than in the PbyP group (33 ± 7 ms; p = .02). In the MPM group, the mapping time (35 ± 24 vs. 53 ± 31 min in PbyP; p = .03) and procedural duration (126 ± 42 vs. 153 ± 39 min in PbyP; p = .02) were significantly shorter. There was no significant difference in radiofrequency and fluoroscopy times, acute procedural success, and arrhythmia recurrence. CONCLUSION: MPM with the HDG catheter for focal tachycardias identified earlier activation times and was associated with shorter mapping and procedure duration with equivalent success to PbyP mapping.

Clinical impact of rotor ablation in atrial fibrillation: a systematic review.

Aims: Rotor mapping and ablation have gained favour over the recent years as an emerging ablation strategy targeting drivers of atrial fibrillation (AF). Their efficacy, however, has been a topic of great debate with variable outcomes across centres. The aim of this study was to systematically review the recent medical literature to determine the medium-term outcomes of rotor ablation in patients with paroxysmal atrial fibrillation (PAF) and persistent atrial fibrillation (PeAF). Methods and results: A systematic search of the contemporary scientific literature (PubMed and EMBASE) was performed in August 2017. Only studies assessing arrhythmia-free survival from rotor ablation of AF were included. We used the random-effects model to assess the primary outcome of pooled medium-term single-procedure AF-free survival for both PAF and PeAF. Success rates from multiple procedures and complication rates were also examined. We included 11 observational studies (4 PAF and 10 PeAF) with a total of 556 patients (166 PAF and 390 PeAF). Pooled single-procedure freedom from AF was 37.8% [95% confidence interval 5.6-86.3%] at a mean follow-up period of 13.8 ± 1.8 months for PAF and 59.2% (95% CI 41.4-74.9%) at a mean follow-up period of 12.9 ± 6 months for PeAF. There was a marked heterogeneity between studies (I2 = 93.8% for PAF and 88.3% for PeAF). The mean complication rate of rotor ablation among the reported studies was 3.4%. Conclusion: The wide variability in success rate between different centres performing rotor ablations suggests that the optimal ablation strategy, particularly targeting rotors, is unclear. Results from randomized studies are necessary before this technique can be considered as an established clinical tool.

Pulmonary Veins Function as Echo Chambers in Persistent Atrial Fibrillation: Circuitous Re-Entry Generates Outgoing Wavefronts.

BACKGROUND: Although the substrate in persistent atrial fibrillation (PeAF) is not limited to the pulmonary veins (PVs), PV isolation (PVI) remains the cornerstone ablation strategy. OBJECTIVES: The aim of this study was to describe the mechanism of outgoing wavefronts (WFs) originating in the PV sleeves during PeAF. METHODS: Eleven patients presenting for first-time PeAF ablation were recruited (mean age 63.1 ± 10.9 years, 91% men). A 64-electrode catheter (Constellation; 38 mm) was positioned within the PV under fluoroscopic guidance. An inverse mapping technique was used to reconstruct unipolar atrial electrograms on the PV surface, and the resulting phase maps were used to identify incoming and outgoing WFs at the PV junction and to classify focal and re-entrant activity within the PV sleeves. RESULTS: During PeAF, the PVs gave rise to outgoing WFs with a frequency of 3.7 s-1 (Q1-Q3: 3.4-5.4 s-1) compared with 3.6 s-1 (Q1-Q3: 2.8-4.2 s-1) for incoming WFs. Circuitous macroscopic re-entry was the dominant mechanism driving outgoing WFs (frequency of re-entry 2.7 s-1 [Q1-Q3: 2.0-3.3 s-1] compared with focal activity 1.4 s-1 [Q1-Q3: 1.1-1.5 s-1]; P < 0.006). This was initiated by incoming WFs in 80% of cases. Consecutive focal activation from the same location was infrequent (10.0% ± 6.6%, n = 10). Rotors ≥360° were never observed. The median ratio (R) of outgoing to incoming WF frequency was 1.14 (Q1-Q3: 0.84-1.75), with R > 1 in 6 of 11 PVs. CONCLUSIONS: Electric activity generated by PV sleeves during PeAF is due mainly to circuitous re-entry initiated by incoming waves, frequently with R > 1. That is, the PVs act less as drivers of atrial fibrillation than as "echo chambers" that sustain and amplify fibrillatory activity.

Impact of Catheter Ablation on Cognitive Function in Atrial Fibrillation: A Randomized Control Trial.

BACKGROUND: Early postoperative cognitive dysfunction (POCD) has been reported following atrial fibrillation (AF) ablation. However, whether POCD is persistent long-term is unknown. OBJECTIVES: The purpose of this study was to determine if AF catheter ablation is associated with persistent cognitive dysfunction at 12-month follow-up. METHODS: This is a prospective study of 100 patients with symptomatic AF who failed at least 1 antiarrhythmic drug randomized to either ongoing medical therapy or AF catheter ablation and followed up for 12 months. Changes in cognitive performance were assessed using 6 cognitive tests administered at baseline and during follow-up (3, 6, and 12 months). RESULTS: A total of 96 participants completed the study protocol. Mean age was 59 ± 12 years (32% women, 46% with persistent AF). The prevalence of new cognitive dysfunction in the ablation arm compared with the medical arm was as follows: at 3 months: 14% vs 2%; P = 0.03; at 6 months: 4% vs 2%; P = NS; and at 12 months: 0% vs 2%; P = NS. Ablation time was an independent predictor of POCD (P = 0.03). A significant improvement in cognitive scores was seen in 14% of the ablation arm patients at 12 months compared with no patients in the medical arm (P = 0.007). CONCLUSIONS: POCD was observed following AF ablation. However, this was transient with complete recovery at 12-month follow-up.

Sex-Related Differences in Atrial Remodeling in Patients With Atrial Fibrillation: Relationship to Ablation Outcomes.

BACKGROUND: Population studies have demonstrated a range of sex differences including a higher prevalence of atrial fibrillation (AF) in men and a higher risk of AF recurrence in women. However, the underlying reasons for this higher recurrence are unknown. This study evaluated whether sex-based electrophysiological substrate differences exist to account for worse AF ablation outcomes in women. METHODS: High-density electroanatomic mapping of the left atrium was performed in 116 consecutive patients with AF. Regional analysis was performed across 6 left atrium segments. High-density maps were created using a multipolar catheter (Biosense Webster) during distal coronary sinus pacing at 600 and 300 ms. Mean voltage and conduction velocity was determined. Complex fractionated signals and double potentials were manually annotated. RESULTS: Overall, 42 (36%) were female, mean age was 61±8 years and AF was persistent in 52%. Global mean voltage was significantly lower in females compared with males at 600 ms (1.46±0.17 versus 1.84±0.15 mV, P<0.001) and 300 ms (1.27±0.18 versus 1.57±0.18 mV, P=0.013) pacing. These differences were seen uniformly across the left atrium. Females demonstrated significant conduction velocity slowing (34.9±6.1 versus 44.1±6.9 cm/s, P=0.002) and greater proportion of complex fractionated signals (9.9±1.7% versus 6.0±1.7%, P=0.014). After a median follow-up of 22 months (Q1-Q3: 15-29), females had significantly lower single-procedure (22 [54%] versus 54 [75%], P=0.029) and multiprocedure (24 [59%] versus 60 [83%], P=0.005) arrhythmia-free survival. Female sex and persistent AF were independent predictors of single and multiprocedure arrhythmia recurrence. CONCLUSIONS: Female patients demonstrated more advanced atrial remodeling on high-density electroanatomic mapping and greater post-AF ablation arrhythmia recurrence compared with males. These changes may contribute to sex-based differences in the clinical course of females with AF and in part explain the higher risk of recurrence. Graphic Abstract: A graphic abstract is available for this article.

Insights From Simultaneous Left and Right Atrial Septal Mapping in Patients With Persistent Atrial Fibrillation.

BACKGROUND: The interatrial septum (IAS) is thought to be involved in the mechanism of persistent atrial fibrillation (PeAF). Simultaneous contact mapping of both sides of the IAS has not been performed previously. OBJECTIVES: The purpose of this study was to describe wave front (WF) activation patterns and extent of left and right atrial septal electrical dissociation in patients with PeAF. METHODS: Simultaneous mapping of both atrial septal surfaces using 2 high-density grid catheters was performed. Filtered electrograms of continuous atrial fibrillation, sinus rhythm (SR), and atrial pacing recordings were exported to MATLAB for off-line phase/activation analysis, and activation patterns on paired surfaces were analyzed. WF activation patterns between the 2 grids were evaluated to determine whether activation WFs were associated or dissociated. RESULTS: Eight patients with PeAF undergoing catheter ablation were included. Complete dissociation of WF activation patterns between the 2 sides of the septum existed throughout the mapping period with no 2 consecutive WF activation patterns matching. Single linear WFs were the most prevalent activation pattern on both septal grids. No focal breakthroughs were seen. Transient rotational activity was seen in 10% of phase activations. During SR and atrial pacing, both grids appeared to be activated independent of each other with no evidence of contralateral conduction across the 2 grids. CONCLUSIONS: Simultaneous biatrial septal mapping of human PeAF, SR, and atrial pacing shows complete WF dissociation between the left and right IAS with no evidence of trans-septal conduction, indicating that the 2 sides function as electrically discrete structures. No stable septal drivers were observed. These findings may have implications for mapping and ablation of PeAF.

Impact of CPAP on the Atrial Fibrillation Substrate in Obstructive Sleep Apnea: The SLEEP-AF Study.

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.

Catheter ablation for atrial fibrillation: current indications and evolving technologies.

Catheter ablation for atrial fibrillation (AF) has emerged as an important rhythm-control strategy and is by far the most common cardiac ablation procedure performed worldwide. Current guidelines recommend the procedure in symptomatic patients with paroxysmal or persistent AF who are refractory or intolerant to antiarrhythmic drugs. The procedure might also be considered as a first-line approach in selected asymptomatic patients. Data from large registries indicate that AF ablation might reduce mortality and the risk of heart failure and stroke, but evidence from randomized controlled trials is mixed. Pulmonary vein isolation using point-by-point radiofrequency or with the cryoballoon remains the cornerstone technique in AF ablation. Additional atrial ablation can be performed in patients with persistent AF, but its benefits are largely unproven. Technological advances in the past decade have focused on achieving durable vein isolation, reducing procedure duration and improving safety. Numerous exciting new technologies are in various stages of development. In this Review, we discuss the relevant data to support the recommended and evolving indications for catheter ablation of AF, describe the different ablation techniques, and highlight the latest advances in technology that aim to improve its safety and efficacy. We also discuss lifestyle modification strategies to improve ablation outcomes.

P-Wave Morphology in Focal Atrial Tachycardia: An Updated Algorithm to Predict Site of Origin.

OBJECTIVES: This study sought to report P-wave morphology (PWM) from a series of paraseptal (PS) atrial tachycardia (AT), revise then prospectively evaluate a simplified PWM algorithm against a contemporary consecutive cohort with focal AT. BACKGROUND: The 2006 PWM algorithm was useful in predicting the origin of focal AT. An updated algorithm was developed given advances in multipolar 3-dimensional mapping, potential limitations of PWM in separating PS sites, and a renewed interest in the P-wave in mapping non-pulmonary vein triggers. METHODS: The PWM from a consecutive series of 67 patients with PS AT were analyzed. PS sites included were coronary sinus ostium, perinodal, left and right septum, septal tricuspid annulus, superior mitral annulus, and noncoronary cusp. Next the P-wave algorithm was revised and prospectively evaluated by 3 blinded assessors. RESULTS: The P-wave for PS sites was neg/pos (n = 50), iso/pos (n = 10), or isoelectric (n = 4) in lead V1 (96%). The P-wave algorithm was modified and prospectively applied to 30 consecutive patients with focal AT who underwent successful ablation. Foci (n = 30) originated from the right atrium (33.3%), left atrium (30%), and PS (36.7%). Using the PW algorithm, the correct anatomic location was identified in 93%. Incorrect interpretation of the terminal positive P-wave component (n = 3) and initial negative P-wave deflection (n = 1) in lead V1 misidentified 4 paraseptal cases. CONCLUSIONS: The revised PWM algorithm offers a simplified and accurate method of localizing the responsible site for focal AT. The P-wave remains an important first step in mapping atrial arrhythmias.

Atrial Fibrillation Structural Substrates: Aetiology, Identification and Implications.

Atrial remodelling in AF underlines the electrical, structural and mechanical changes in the atria of patients with AF. Several risk factors for AF contribute to the development of the atrial substrate, with some evidence that atrial remodelling reversal is possible with targeted intervention. In this article, the authors review the electrophysiological changes that characterise the atrial substrate in patients with AF risk factors. They also discuss the pitfalls of mapping the atrial substrate and the implications for developing tailored ablation strategies to improve outcomes in patients with AF.