Interatrial conduction time is associated with left atrial low voltage area and predicts the recurrence after single atrial fibrillation ablation.

Background: Interatrial conduction time (IACT) prolongs in fibrotic left atrium. We tested the hypothesis that IACT is related to left atrial low voltage area (LVA) and predicts the recurrence after single atrial fibrillation (AF) ablation. Methods: One hundred sixty-four consecutive AF patients (79 non-paroxysmal) who underwent initial ablation in our institute were analyzed. IACT and LVA were defined as interval from the onset of P-wave to the basal left atrial appendage (P-LAA) activation, and area with bipolar electrogram < 0.5 mV covering over 5% of the total left atrial surface area during sinus rhythm, respectively. Pulmonary vein antrum isolation, non-PV foci ablation, and atrial tachycardia (AT) ablation were performed without substrate modification. Results: LVA was frequently identified in patients with prolonged P-LAA ≥ 84 ms (n  = 28) compared with patients with P-LAA < 84 ms (n  = 136). Patients with P-LAA ≥ 84 ms were older (71 ± 10 vs. 65 ± 10 years, p  = .0061), and had more frequent non-paroxysmal AF (75% vs. 43%, p  = .0018), larger left atrial diameter (43.5 ± 4.5 vs. 39.3 ± 5.7 mm, p  = .0003), and higher E/e' ratio (14.4 ± 6.5 vs. 10.5 ± 3.7, p  < .0001) compared with P-LAA < 84 ms patients. After a mean follow-up period of 665 ± 153 days, Kaplan-Meier curve analysis showed that AF/AT recurrences was more frequently observed in patients with prolonged P-LAA (Log-rank p  = .0001). Additionally, univariate analysis revealed that P-LAA prolongation (OR = 1.055 per 1 ms, 95% CI: 1.028-1.087, p  < .0001) and the existence of LVA (OR = 5.000, 95% CI: 1.653-14.485 p  = .0053) were predictors of AF/AT recurrences after single AF ablation. Conclusions: Our results suggested that prolonged IACT as measured by P-LAA was associated with LVA and predicts AT/AF recurrence after single AF ablation.