Quantitative Analysis of the Isolation Area During the Chronic Phase After a 28-mm Second-Generation Cryoballoon Ablation Demarcated by High-Resolution Electroanatomic Mapping

The post-second-generation cryoballoon (CB) ablation isolation area during the chronic phase has not been described. The aim of this study was to quantitatively evaluate the chronic-phase isolation area after 28-mm second-generation CB ablation and compare it to the estimated conventional radiofrequency circumferential pulmonary vein isolation (CPVI) line.Thirty-two patients with paroxysmal atrial fibrillation underwent pulmonary vein (PV) isolation using second-generation CB. After a median of 6.0 (4.0-9.0) months, the PV isolation area was evaluated using high-resolution mapping (1-mm electrode, 2-mm interelectrode spacing; 527±99 points per map) and pacing techniques in all patients (17 with and 15 without arrhythmia recurrence beyond blanking period) and compared with estimated conventional radiofrequency CPVI area. PV reconnections were observed in 34 of 126 PVs (27.0%) among 21 of 32 patients (65.6%), which were eliminated by a median of 1.0 (1.0-3.0) focal radiofrequency application. The left- and right-sided PV antrum isolation area and nonablated posterior wall areas were 9.8±1.7, 8.1±2.3, and 17.0±6.1 cm(2), respectively. The cryoablated areas were significantly smaller than the estimated conventional radiofrequency CPVI areas in all but the right inferior PV. The difference was highest in the left superior PV. In 2 patients (6.3%), recurrent atrial fibrillation originated from the foci identified at the left superior PV antrum outside the CB isolation area but inside the estimated conventional radiofrequency CPVI line.Although the PV isolation areas during the chronic phase after the second-generation CB ablation were generally wide, they were significantly smaller than the area encircled by the CPVI line except at the right inferior PV antrum. Recurrent atrial fibrillation could originate from the left superior PV antrum and could be isolated by a CPVI but not by a CB.