Characterization of Residual Conduction Gaps After HotBalloon-Based Antral Ablation of Atrial Fibrillation　― Evidence From Ultra-High-Resolution 3-Dimensional Mapping

• Published in: Circulation Journal Vol. 83; no. 6; pp. 1206 - 1213
• Main Authors: Nakahara, Shiro, Hori, Yuichi, Fukuda, Reiko, Nishiyama, Naoki, Kobayashi, Sayuki, Sakai, Yoshihiko, Taguchi, Isao
• Format: Journal Article
• Language: English
• Published: Japan The Japanese Circulation Society 24.05.2019
• Subjects: Atrial fibrillation; Conduction gap; Hot balloon ablation; Rhythmia mapping system; Hot balloon ablation; Rhythmia mapping system; Atrial fibrillation; Conduction gap
• ISSN: 1346-9843; 1347-4820
• DOI: 10.1253/circj.CJ-18-1051

Background:The electrophysiological characteristics of residual conduction gaps between the left atrium (LA) and pulmonary veins (PVs) after HotBalloon-based wide antral ablation (HBWA) of atrial fibrillation (AF) remain incompletely understood. This study aimed to characterize the residual gaps by means of ultra-high-resolution mapping.Methods and Results:A total of 55 AF patients underwent HBWA by a predetermined protocol (6-shot total-based antral approach). LA-PV maps were created using 64-electrode minibasket catheters. In total, 55 residual gaps were identified among 26 (47%) patients. Residual gaps included 33 left superior (LS: 60%), 10 left inferior (18%), 6 right superior (11%), and 6 right inferior (11%) PVs. Those gaps demonstrated both extremely lower bipolar amplitudes (0.11 [interquartile range: 0.06–0.27] mV) and conduction velocities (0.75±0.27 m/s); however, the length was confined (10.3±4.1 mm) except for the LSPV anterior carina (12.2±2.4 mm) region. Among the carina regions, all gaps had far-field potentials consistently added to the PV potentials. Left atrial appendage pacing to split the far-field activity identified confined gap regions (6.7±1.9 mm). Touch-up ablation eliminated the residual PV potentials in all cases.Conclusions:HBWA resulted in a certain degree of residual gap conduction in particular antral regions. These gaps exhibited narrow lengths with lower amplitudes, and often had far-field recordings from the left atrial appendage. Combined with pacing maneuvers, ultra-high-resolution activation maps could both visualize all confined gaps and ensure a bare minimum of touch-up ablations in all patients with gap conduction.