Fehmi Keçe

Abstract Introduction Efficacy of cryoballoon ablation depends on balloon-tissue contact and ablation duration. Prolonged duration may increase extra-cardiac complications. The aim of this study is to determine the optimal additional ablation duration after acute pulmonary vein isolation (PVI). Methods Consecutive patients with paroxysmal AF were randomized to 3 groups according to additional ablation duration (90, 120 or 150s) after acute PVI (time-to-isolation). Primary outcome was reconnection/dormant conduction (DC) after a 30 minutes waiting period. If present, additional 240s ablations were performed. Ablations without time-to-isolation <90s, esophageal temperature <18°C or decreased phrenic nerve capture were aborted. Patients were followed with 24-hour Holter monitoring at 3, 6 and 12 months. Results Seventy-five study patients (60±11 years, 48 male) were included. Reconnection/DC per vein significantly decreased (22, 6 and 4%) while aborted ablations remained stable (respectively 4, 5 and 7%) among the 90, 120 and 150s groups. A shorter cryo-application time, longer time-to-isolation, higher balloon temperature and unsuccessful ablations predicted reconnection/DC. Freedom of AF was respectively 52, 56 and 72% in 90, 120 and 150s groups (p=0.27), while repeated procedures significantly decreased from 36% to 4% (p=0.041) in the longer duration group compared to shorter duration group (150s vs 90s group). In multivariate Cox-regression only reconnection/DC predicted recurrence. Conclusion Prolonging ablation duration after time-to-isolation significantly decreased reconnection/ DC and repeated procedures, while recurrences and complications rates were similar. In a time-to-isolation approach, an additional ablation of 150s ablation is the most appropriate. Clinical Trial Registration – Dutch National Trial Register- NL47833.058.14.