Dynamic changes of left atrial substrate over time following pulmonary vein isolation: the Progress-AF study.

AIMS: Little is known about dynamic changes of the left atrial (LA) substrate over time in patients with atrial fibrillation (AF). This study aims to evaluate substrate changes following pulmonary vein isolation (PVI). METHODS AND RESULTS: In our prospective observational study, consecutive patients undergoing first PVI-only and redo ablation were included. High-density maps of the two procedures were compared. Progression or regression was diagnosed if a significant concordant decrease or increase in bipolar voltages in ≥2 segments was observed, respectively. In 28 patients (61.2 ± 9.5 years, 39% female, 53.5% persistent AF), 111.013 voltage points from 56 high-density LA maps (1.982 points/patient) were analysed. Comparing the high-density maps of the first and second procedures, in the progression group (17 patients, 61%), there was a decrease in global (-35%, P < 0.001) and all regional voltages. In the regression group (11 patients, 39%), there was an increase in global (+43%, P < 0.001) and regional voltages. Comparing the progression with the regression group, the area of low-voltage zone (LVZ) increased (+3.5 vs. -4.5 cm2, P < 0.001) and LA activation time prolonged (+8.0 vs. -9.1 ms, P = 0.005). Baseline clinical parameters did not predict progression or regression. In patients with substrate progression, pulmonary veins (PVs) were more frequently isolated (P = 0.02) and the AF pattern at recurrence was more frequently persistent (P = 0.005). CONCLUSION: Our study describes bidirectional dynamic properties of the LA substrate with concordant either progressive or regressive changes. Regression occurs with reduced AF burden after the first procedure, while progression is associated with persistent AF recurrence despite durable PV isolation. The dynamic nature of LA substrate poses questions about LVZ-based ablation strategies.

Gender-Related Differences in Atrial Substrate in Patients with Atrial Fibrillation.

Gender-related differences have been reported in patients who underwent pulmonary vein isolation (PVI). Atrial substrate plays a role in the outcomes after ablation but gender-related differences in atrial substrate have never been described in detail. We sought to analyze gender-related differences in atrial remodeling (spontaneous low-voltage zones [LVZs]) and their clinical relevance after PVI. We conducted a prospective multicenter study, including consecutive patients who underwent first PVI-only atrial fibrillation (AF) ablation. LVZs were analyzed on high-density electroanatomical maps collected with multipolar catheter, before PVI. In total, 262 patients (61 ± 11 years, 31% female, 50% persistent AF) were followed for 28 months. In women, LVZs were larger (10% vs 4% of left atrial surface [p <0.001]) and female gender was independently associated with fourfold higher risk of having advanced (LVZ > 15%) atrial remodeling (odds ratio 4.56, p <0.001). AF recurrence-free survival was not different between men and women (log-rank p = 0.2). Although LVZs were independently associated higher AF recurrences at multivariate analysis (hazard ratio [HR] 1.2, p = 0.038), female gender was not (HR 1.4, p = 0.211). Specifically, the LVZ cutoff to predict outcomes was different in men and women: >5% in men (HR 3.0, p <0.001), >15% in women (HR 2.7, p = 0.02). In conclusion, women have more widespread LVZ in all left atrial regions. Despite more extensive atrial remodeling, the AF recurrence rate is similar in men and women, and LVZs become prognostic in women only at high burden (>15%). LVZs seem to have a different prognostic role in men and women.

Anterior mitral line in patients with persistent atrial fibrillation and anterior scar: A multicenter matched comparison-The MiLine study.

BACKGROUND: The benefit of an anterior mitral line (AML) in patients with persistent atrial fibrillation (AF) and anterior atrial scar undergoing ablation has never been investigated. OBJECTIVE: The purpose of this study was to evaluate the outcomes of AML in addition to standard treatment compared to standard treatment alone (no AML) in this subset of patients. METHODS: Patients with persistent AF and anterior low-voltage zone (LVZ) treated with AML in 3 centers were retrospectively enrolled. The patients were matched in 1:1 fashion with patients having persistent AF and anterior LVZ who underwent conventional ablation in the same centers. Matching parameters were age, LVZ burden, and repeated ablation. Primary endpoint was AF/atrial tachycardia (AT) recurrence. RESULTS: One hundred eight-six patients (age 66 ± 9 years; 34% women) were selected and divided into 2 matched groups. Bidirectional conduction block was achieved in 95% of AML. After median follow-up of 2 years, AF/AT recurrence occurred in 29% of the patients in the AML group vs 48% in the no AML group (log-rank P = .024). On Cox regression multivariate analysis, left atrial volume (hazard ratio [HR] 1.03; P = .006) and AML (HR 0.46; P = .003) were significantly associated with the primary endpoint. On univariate logistic regression, lower body mass index, older age, extensive anterior LVZ, and position of the left atrial activation breakthrough away from the AML were associated with first-pass AML block. CONCLUSION: In this retrospective matched analysis of patients with persistent AF and anterior scar, AML in addition to standard treatment was associated with improved AF/AT-free survival compared to standard treatment alone.

Characterization of Atrial Substrate to Predict the Success of Pulmonary Vein Isolation: The Prospective, Multicenter MASH-AF II (Multipolar Atrial Substrate High Density Mapping in Atrial Fibrillation) Study.

Background Left atrial substrate may have mechanistic relevance for ablation of atrial fibrillation (AF). We sought to analyze the relationship between low-voltage zones (LVZs), transition zones, and AF recurrence in patients undergoing pulmonary vein isolation. Methods and Results We conducted a prospective multicenter study on consecutive patients undergoing pulmonary vein isolation-only approach. LVZs and transition zones (0.5-1 mV) were analyzed offline on high-density electroanatomical maps collected before pulmonary vein isolation. Overall, 262 patients (61±11 years, 31% female) with paroxysmal (130 pts) or persistent (132 pts) AF were included. After 28 months of follow-up, 73 (28%) patients experienced recurrence. An extension of more than 5% LVZ in paroxysmal AF and more than 15% in persistent AF was associated with recurrence (hazard ratio [HR], 4.4 [95% CI, 2.0-9.8], P<0.001 and HR, 1.9 [95% CI, 1.1-3.7], P=0.04, respectively). Significant association was found between LVZs and transition zones and between LVZs and left atrial volume index (LAVI) (both P<0.001). Thirty percent of patients had significantly increased LAVI without LVZs. Eight percent of patients had LVZs despite normal LAVI. Older age, female sex, oncological history, and increased AF recurrence characterized the latter subgroup. Conclusions In patients undergoing first pulmonary vein isolation, the impact of LVZs on outcomes occurs with lower burden in paroxysmal than persistent AF, suggesting that not all LVZs have equal prognostic implications. A proportional area of moderately decreased voltages accompanies LVZs, suggesting a continuous substrate instead of the dichotomous division of healthy or diseased tissue. LAVI generally correlates with LVZs, but a small subgroup of patients may present with disproportionate atrial remodeling, despite normal LAVI.

Reproducibility and predictive value of a simple novel method to measure atrial fibrillation cycle length in persistent atrial fibrillation - FARS-AF study.

INTRODUCTION: Different methods are used for atrial fibrillation (AF) cycle length (CL) measurement with variable results. Previous studies of pulmonary vein (PV) CL measurement showed contradictory results on predicting PV isolation (PVI) efficacy. A novel simple method of measuring the average of 10 consecutive Fastest Atrial Repetitive Similar morphology signal (FARS10 )-CL to characterize local atrial activity rate was evaluated prospectively. METHODS: The intra-observer reproducibility of FARS10 -CL and traditional AF-CL measurement of continuously fragmented coronary sinus (CS) signals were tested. We prospectively enrolled 100 consecutive patients (62 ± 10 years, 72% male) undergoing wide antral PVI only ablation for persistent AF, measured PV-FARS10 -CLs, and evaluated long-term outcome. RESULTS: The Kendall area correlation between repeated traditional AF-CL measurements was -0.006 and between repeated FARS10 -CL measurements in the right and left atrial appendages, CS and PVs were 0.944, 0.859, 0.882, 0.675-0.955, respectively. Patients with recurrent atrial tachyarrhythmia had significantly longer fastest PV-FARS10 -CL (172 ± 41 vs. 156 ± 41 ms, p = .047). Patients with high burden of spontaneous low-voltage zone (LVZ) had significantly longer fastest PV-FARS10 -CL. Freedom from recurrent tachyarrhythmia at 24 months was 85% versus 59% in patients with fastest PV-FARS10 -CL ≤ 140 versus >140 ms, p = .0018, respectively. In multivariable analysis fastest PV-FARS10 -CL ≤ 140 ms was the only significant predictor of freedom from recurrent tachyarrhythmia. CONCLUSIONS: FARS10 -CL measurements have a high reproducibility in contrast to traditional AF-CL measurement of continuously fragmented CS signals. Patients with high burden of LVZ have longer fastest PV-FARS10 -CLs. Fastest PV-FARS10 -CL ≤ 140 ms is associated with a high success of wide antral PVI-only ablation approach in persistent AF.

Less Pulmonary Vein Reconnection at Redo Procedures Following Radiofrequency Point-by-Point Antral Pulmonary Vein Isolation With the Use of Contemporary Catheter Ablation Technologies.

OBJECTIVES: This study investigated whether real-world use of contemporary technologies changed pulmonary vein (PV) reconnection and redo pulmonary vein isolation (PVI) procedure frequencies. BACKGROUND: Previous studies consistently reported that following PVI recurrence of PV conduction is observed in >80% of patients. METHODS: Consecutive patients undergoing 529 first and/or redo radiofrequency point-by-point PVI between January 2013 and December 2016 were included. RESULTS: Between 2013 and 2016, redo PVI rate in atrial fibrillation significantly decreased (p < 0.001); in ≤12 months, first redo PVI rate decreased from 19% to 4%. The percentage of patients having PV reconnection at second PVI significantly decreased from 90% to 29% (p = 0.001). One PVI was performed in 393 and >1 in 79 patients. Female sex was associated with >1 PVI (hazard ratio [HR]: 1.86; 95% confidence interval [CI]: 1.10 to 3.13; p = 0.02). Sixty patients underwent first and second PVI in the study period. Female sex (HR: 2.79; 95% CI: 1.67 to 4.64; p < 0.001) and left atrial diameter (HR: 1.05; 95% CI: 1.01 to 1.08; p = 0.01) were associated with more and use of automatic ablation annotation algorithm during first PVI with fewer (HR: 0.54; 95% CI: 0.32 to 0.92; p = 0.02) redo PVI procedures. In 31 of 60 patients, ≥1 PV was reconnected at second PVI. The need for "touch-up" applications at the first PVI was the only predictor of PV reconnection. CONCLUSIONS: Redo rate in atrial fibrillation and PV reconnection at redo PVI significantly decreased in recent years. Male sex, left atrial diameter, and use of automatic ablation annotation algorithm at first PVI were associated with fewer redo procedures. First-pass isolation was associated with lower PV reconnection rate at second procedure. Female sex was associated with more redo procedures but not higher PV reconnection frequencies.