Understanding electrical pulmonary vein antrum for paroxysmal atrial fibrillation: Further look into superhigh-density electroanatomic mapping of the left atrium.

Background: An isolation line placed at the pulmonary vein antrum (PVA) area is superior to ostium level in atrial fibrillation (AF) control. However, less is known about the electrophysiologic characteristics of the PVA.

Objective: The aim of this study was to describe the electrophysiologic properties of the PVA.

Methods: High-density mapping of the left atrium was performed in 18 paroxysmal AF (PAF) patients and 9 age- and sex-matched paroxysmal supraventricular tachycardia (PSVT) patients. Each PVA was divided into 8 segments, and the pulmonary vein (PV) was divided into 4 segments. The electrophysiologic properties included slow conduction, complex fractionated electrograms, and effective refractory period (ERP).

Results: Slow conduction was more prevalent at the PVA (43.2% ± 19.5% vs 14.7% ± 13.0%; P = .001) and PV (61.9% ± 16.4% vs 9.1% ± 9.0%; P < .001) in PAF patients than in PSVT patients during sinus rhythm. Similarly, the area with complex fractionated electrograms was significantly larger at the PVA (133.8 [61.6-233.2] mm vs 0.0 [0.0-41.4] mm; P = .011) in PAF patients during sinus rhythm. The ERP of the PVA was longer in PAF patients than in control at the drive length of 600 ms (260 [230-280] ms vs 220 [190-250] ms; P = .001) and 400 ms (230 [205-250] ms vs 200 [190-220] ms; P = .007). The ERP net difference between the PV and PVA is larger in PAF patients than in control both at 600-ms pacing (40 [20-70] ms vs 10 [10-30] ms; P < .001) and at 400-ms pacing (40 [20-60] ms vs 20 [10-30] ms; P < .001).

Conclusion: PAF patients have the PVA electrical substrate including slow conduction, complex fractionated electrograms, and ERP dispersion.