Key result
Achieving mitral isthmus block during repeat ablation for long-standing persistent AF was associated with improved ATa-free survival (HR 0.012; 95% CI 0.000-0.456; P=0.02).
Why the study?
Mitral isthmus ablation was limited due to technical challenges during index ablation for long-standing persistent AF, leaving the role of adjunctive mitral isthmus ablation controversial.
Does achieving mitral isthmus (MI) block improve atrial tachyarrhythmia-free survival in patients undergoing reablation for long-standing persistent atrial fibrillation?
Cohort (n=41)
Does achieving mitral isthmus (MI) block improve atrial tachyarrhythmia-free survival in patients undergoing reablation for long-standing persistent atrial fibrillation?
Effect estimate: HR 0.012 (95% CI 0.000-0.456)
Absolute Event Rate: 83.8% vs 25%
p-value: p=0.02
Achieving mitral isthmus block during repeat ablation for long-standing persistent atrial fibrillation is feasible and significantly associated with improved freedom from recurrent atrial tachyarrhythmias.
Supports mitral isthmus block as a reablation target in long-standing persistent AF; hypothesis-generating and should not change practice without randomized confirmation.
BACKGROUND: Mitral isthmus (MI) ablation was limited due to technical challenges in the index ablation for long-standing persistent atrial fibrillation (LPeAF). The role of adjunctive MI ablation was controversial. HYPOTHESIS: MI block could be achieved in most patients undergoing repeat LPeAF ablation and was associated with favorable clinical outcomes. METHODS: Of 87 consecutively patients undergoing reablation for recurrent atrial tachyarrhythmias (ATa), 41 patients with residual MI conduction but without pulmonary vein reconnection or left atrial roof conduction were enrolled to treat recurrent atrial flutter (AFL) (n = 20) and AF (n = 21). After AFL ablation and AF cardioversion, MI conduction gaps (CGs) were mapped and closed. RESULTS: MI line was successfully blocked in 37 (90.2%) of 41 patients after closing 1.4 ± 0.5 CGs (31 endocardial CGs and 16 epicardial ones) in the initial MI lines. CGs were more often located at the endocardial sites close to the lateral ridge between left atrial appendage and left-sided PVs, midportion of MI and at the epicardial breakthroughs within coronary sinus. At the end of 16.0 ± 1.9 months' follow-up, 31 (83.8%) of 37 patients with MI block and 1 of 4 patients without MI block were free of further recurrence of ATa off anti-arrhythmic drugs. MI block was positively associated with ATa-free survival by Cox's regression analysis (hazard ratio [HR]: 0.012, 95% confidence interval [CI]: 0.000-0.456, P = .02). CONCLUSIONS: MI block could be achieved in the majority of patients during repeat ablation for LPeAF. MI block was associated with favorable clinical outcomes after LPeAF reablation.
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Wang et al. (2020) conducted a cohort in Recurrent atrial tachyarrhythmias after long-standing persistent atrial fibrillation ablation (n=41). Mitral isthmus block vs. Without mitral isthmus block was evaluated on Freedom from further recurrence of atrial tachyarrhythmias off anti-arrhythmic drugs (HR 0.012, 95% CI 0.000-0.456, p=0.02). Achieving mitral isthmus block during repeat ablation for long-standing persistent AF was associated with improved ATa-free survival (HR 0.012; 95% CI 0.000-0.456; P=0.02).
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