Second generation cryoballoon ablation for persistent atrial fibrillation: an updated meta-analysis

Background Catheter ablation is an established treatment option for patients with symptomatic atrial fibrillation (AF). The cornerstone of AF ablation is pulmonary vein isolation (PVI). The second-generation cryoballoon (2G-CB) has shown non-inferiority to radiofrequency (RF) ablation in paroxysmal AF in several trials. Growing evidence suggests that 2G-CB is also effective in patients with persistent AF (perAF). The aim of this study was to summarize and analyze available data on safety and mid-term (≥ 12 months) efficacy of PVI using 2G-CB in patients with perAF. Methods We did a search in PubMed, Web of Science, Cochrane Library, and clinicaltrials.gov in December 2016 for studies of 2G-CB ablation for perAF. Studies reporting clinical success rates at a follow-up (FU) of ≥ 12 months were included. Success was defined as freedom from any atrial arrhythmia lasting > 30 s after an initial blanking period of 3 months. Acute success and complication rates were also assessed. Data were analyzed applying random-effects model. Results A total of 917 patients from 11 studies meeting study inclusion criteria were analyzed. After a mean FU of 16.7 ± 3.0 months, 68.9% were free from recurrences [95% confidence interval (CI) 63.4–74.7%]. Overall acute success rate was 99.7% (95% CI 99.2–100%). Complications occurred in 5.5% (95% CI 2.4–9.6%). Vascular access complications were the most frequent 3.3% (95% CI 1.5–5.6%). The rate of phrenic nerve palsy/injury was 2.09% (95% CI 0.8–3.9%). No death, stroke or myocardial infarction was reported. Conclusion The 2G-CB seems to be safe and effective in the treatment of perAF in the mid-term.