Effects of additional ablation of low‐voltage areas after Box isolation for persistent atrial fibrillation

Abstract

Abstract Background Previous studies reported that ablation of low‐voltage areas ( LVA s) after pulmonary vein isolation ( PVI ) improves the success rate in persistent atrial fibrillation (Per AF ) patients with LVA s. However, the need for LVA ablation in addition to the posterior left atrial isolation, Box isolation ( BOXI ), for Per AF is unclear. We evaluated the effects of LVA ablation after BOXI for Per AF with LVA s. Methods In 115 patients with Per AF (75 longstanding Per AF ), LA voltage maps were created during sinus rhythm after PVI . Subsequently, BOXI was performed. In 61 patients without LVA s (<0.5 mV ), BOXI alone was performed. Fifty‐four patients with LVA s were randomly assigned to BOXI plus LVA ablation (33 patients) or BOXI alone (21 patients). Results The rate of AF termination or cardioversion after BOXI was significantly higher than that after PVI (100% vs 88%, P < 0.001). The inducibility of atrial tachyarrhythmia after BOXI was significantly lower than that after PVI (27% vs 100%, P < 0.001). During 24 ± 9 months of follow‐up after a single procedure, atrial tachyarrhythmia‐free rate in the patients with LVA s, was significantly lower than that without LVA s (65% vs 82%, P = 0.043). However, the success rate was not significantly different between the BOXI plus LVA ablation group and the BOXI alone group of patients with LVA s (67% vs 62%, P = 0.722). Conclusion BOXI facilitates AF termination and its non‐inducibility. Among patients with Per AF , BOXI alone may be adequate in cases without LVA s. Although cases with LVA s have higher risk of AF recurrence, additional LVA ablation does not improve the outcomes much.