Comparison of ablation efficacy with cryoballoon or radiofrequency for the treatment of atrial fibrillation: a meta-analysis of randomized controlled trials

Radiofrequency catheter ablation (RFCA) of pulmonary vein isolation (PVI) has been the standard strategy for treatment of atrial fibrillation (AF). Cryoballoon ablation (CBA) is also frequently adopted. Here, we conducted a meta-analysis of randomized controlled trials (RCTs) to compare the efficacy of CBA and RFCA in the treatment of AF. PubMed, EMBASE and Cochrane Library were searched up to May 2016, using Boolean operators as follows: (atrial fibrillation OR pulmonary vein isolation) AND (cryoballoon OR radiofrequency ablation). All RCTs directly comparing the efficacy between CBA and RFCA were retrieved. Eight out of 367 studies, involving 1849 patients, were included in this study. The fluoroscopic time was significantly lower in the RFCA group compared with the CBA group (mean difference 2.94; 95% confidence interval [95% CI]: 0.34 to 5.54, P=0.03). However, no significant difference in total procedure time between these two groups by mean difference -11.2 (95% CI: -34.53 to 12.13, P=0.35); Total complications were not significantly different between the two groups (relative risk [RR]: 1.21; 95% CI: 0.71 to 2.04, P=0.49); however, almost all phrenic nerve palsies (PNP) occurred in the CBA group. The CBA group had similar proportion of patients free from AF as the RFCA group at the 12-month follow-up (RR: 1.02; 95% CI: 0.90 to 1.16, P=0.74). Our analysis indicates that, compared with RFCA, CBA is not inferior in total procedure time and complications except for the longer fluoroscopic time. There were also similar proportions of patients free from AF in both groups at the one-year follow-up.