Prospective evaluation of low voltage-guided repeat ablation of atrial fibrillation.

Background: Atrial fibrillation (AF) recurrences following pulmonary vein isolation (PVI) remain a substantial challenge.

Objective: To evaluate repeat ablation of AF combining PVI with substrate-based left atrial ablation targeting low voltage areas (LVA).

Methods: Patients with recurrent AF after prior solely PVI were enrolled. Voltage map was conducted during sinus rhythm. Repeat PVI was performed in case of PV-reconnection. Only if LVA (defined as electrogram amplitudes < 0.5 mV) were present, substrate modification was conducted by creating linear or box lesions. Arrhythmia monitoring was performed for 6 months using a photoplethysmography-based smartphone application.

Results: 58 patients were analysed (37.9% female, median age 66.0 years [IQR 59.8-72.3]). Reconnection of at least 1 PV was found in 49 patients (84.5%). LVA were found in 31 patients (53.4%). An anterior box lesion was created in 39.7%, anterior linear lesion in 8.6%, posterior box lesion in 17.2%, roof line in 34.5%, and posterior mitral isthmus line in 5.2% of the patients. Patients with LVA were more often female (54.8% vs. 18.5% without LVA; p = 0.0045), were at higher age (71.0 years [IQR 66.0-78.0] vs. 62.0 years [IQR 55.0-66.0] without LVA; p < 0.0001), and had higher left atrial volume indexes (50.0ml/m2 [IQR 40.0-61.0] vs. 34.0ml/m2 [IQR 28.0-48.0] without LVA; p = 0.0014). Arrhythmia-free survival was 66.7% in patients without LVA and 48.4% in patients with LVA (HR 0.6063; 95% CI:0.2767-1.329; p = 0.2206).

Conclusions: PV reconnection and the presence of LVA constitute the main findings of repeat ablations of AF. Repeat PVI combined with a tailored ablation approach individually targeting LVA was effective and safe.