P979Persistent atrial fibrillation terminated within the left atrium without recurrence at follow-up demonstrates a gradual intracardiac organization during stepwise ablation

Introduction We previously reported that patients (pts) with recurrence (Rec) after stepwise catheter ablation (step-CA) of persistent atrial fibrillation (pAF) exhibit high bi-atrial intracardiac dominant frequencies (DF) values before ablation, indicative of a severe bi-atrial electro-anatomical remodeling. Purpose Herein, we hypothesized that a gradual decrease in DF values during step-CA is associated with pAF termination and maintenance of sinus rhythm (SR) on the long term. Method In 40 consecutive pts (61±8 yo, sustained AF duration 19±11 months), pulmonary vein isolation (PVI) and left atrium (LA) ablation were performed until pAF termination or cardioversion. 10-sec intracardiac electrograms (EGMs) epochs were recorded before ablation (BL), during PVI and during complex fractionated atrial electrograms (CFAEs) and linear ablation (post_PVI) in the right atrial (RAA) and left atrial (LAA) appendages and in the coronary sinus (CS). DF was defined as the highest peak within the [3–15] Hz EGM spectrum. Rec was defined as any atrial arrhythmia lasting >30 sec during follow-up (FU). Results pAF was terminated within the LA in 70% (28/40, LT) of the pts, while 30% (12/40, NLT) were not. After a mean FU of 34±14 months, all NLT pts had a Rec, while LT pts presented a Rec in 71% (20/28, LT_rec) and remained in SR in 29% (8/28, LT_norec). Figure 1 shows: 1) a gradient in DF values measured in the LAA (panel A), RAA (panel B) and CS (panel C) with the highest values in NLT pts (red), intermediate values in LT_rec pts (yellow) and lowest DF values in LT_norec pts (green); 2) all three groups displayed a gradual intracardiac organization during LA ablation as shown by decreasing DF values (p<0.05, BL vs post_PVI), but the LT_norec pts (green) exhibited the highest relative changes in DF from BL (p<0.05, LT_norec vs NLT, Δ range: −5.31 to −9.69%). Figure 1. Effect of ablation on DF Conclusion Low DF values before ablation and gradual intracardiac organization until pAF termination are associated with maintenance of SR on the long term.

Characteristics and outcomes of patients after multiple (≥3) catheter ablation procedures for atrial fibrillation

Background: Many atrial fibrillation (AF) patients require more than one radiofrequency catheter ablation (RFCA) procedure to maintain sinus rhythm. This study aimed to evaluate risk and risk factors of atrial tachyarrhythmia (ATa) recurrence in patients undergoing multiple (≥3) RFCA procedures for AF. Methods: This single-center, retrospective, observational study enrolled 118 consecutive patients who underwent multiple ablation procedures for paroxysmal and non-paroxysmal AF with circumferential pulmonary vein ablation (CPVA), and bidirectional block of lines with disappearance of complex fractionated atrial electrograms (CFAEs) as index procedural endpoints, respectively. Results: At a median follow-up of 18 (range, 6-91) months after the last procedure (mean, 3.2 procedures), freedom from ATa recurrence was 40.7% (48/118). Initially diagnosed non-paroxysmal AF (P=0.039), baseline LA size (P=0.044), and recurrent AF after the second procedure (P=0.044) were univariate predictors of ATa recurrence, while only the latter (P=0.010) was an independent multivariate predictor (hazard ratio for ATa recurrence of 1.88 [95% CI, 1.16-3.05]. Conversion of recurrent types between AF and AFL/AT occurred in 52.9% (37/70) of patients with ATa recurrence, and 29.2% (14/48) of patients with sinus rhythm after last procedure. Few patients (7.8% [20/257]) recovered PV potential induced recurrent ATa during multiple procedures, and most (87.6% [141/161]) were bystanders of recurrent ATa. Conclusions: Multiple (>3) RFCA for paroxysmal or non-paroxysmal AF yielded unsatisfactory ATa recurrence rates with recurrent AF after the second procedure as multivariate predictor and recovered PV potential as a bystander commonly as underlying mechanism. Conversion of recurrent types between AF and AFL/AT was common.