Clinical outcomes
The median follow-up duration was 372 days [interquartile range, 182–450 days]. Atrial arrhythmia recurrence was observed in 55 (28.8%) of 191 patients, and the 12-month Kaplan–Meier event-free rate was 77.0% (Figure 2). Of 191 patients, AT and AF recurrence were confirmed in 14 (7.3%) and 44 (23.0%) patients, respectively. The persistent type accounted for 59.1% of AF recurrences (26/44 patients). Table 1 shows the comparisons between the patients based on recurrence, with each recurrence pattern in addition to overall recurrence. The prevalence of LAPW ablation, including cryoballoon ablation of the LA roof, was higher in patients without recurrence than in those with recurrence, and the 12-month Kaplan–Meier event-free rate was 79.0% in patients who had undergone cryoballoon ablation of the LAPW and 72.2% in those who had not (p=0.15; Figure 3). When the recurrence rate was analyzed according to recurrence patterns, AF recurrence rate, particularly the persistent AF recurrence rate, was significantly lower in patients who had undergone cryoballoon ablation of the LAPW compared with those who had not, and the 12-month Kaplan–Meier event-free rate was 83.0% (AF recurrence) and 91.3% (persistent AF recurrence) in patients who had undergone cryoballoon ablation of the LAPW and 73.8% (AF recurrence) and 81.4% (persistent AF recurrence) in those who had not (AF recurrence: p=0.09, persistent AF recurrence: p=0.01; Figure 3). Moreover, multivariate analysis using Cox regression analysis identified LAPW cryoballoon ablation as a predictor for freedom of persistent AF recurrence in addition to AAD use and AF duration (Table 3). With regard to AT recurrence, multivariate analysis with Cox regression analysis revealed only AAD use as a predictor of AT recurrence (Table 3). LAPW ablation, including cryoballoon ablation of the LA roof, was not associated with AT recurrence. A wave velocity of trans-mitral flow was measured by transthoracic echocardiography in 94 out of 191 patients, and there was a significant difference between the patients who underwent cryoballoon ablation of the LAPW and those who did not (0.53±0.13 m/sec for the patients who underwent cryoballoon ablation of the LAPW vs. 0.64±0.24 m/sec for those who did not, p=0.01).