Optimizing ablation duration using dormant conduction to reveal incomplete isolation with the second generation...

Area of Science:

• Electrophysiology
• Cardiovascular Medicine
• Medical Technology

Background:

• Cryoballoon ablation efficacy relies on adequate balloon-tissue contact and sufficient ablation duration.
• Prolonged ablation times may increase the risk of extracardiac complications.
• Determining the optimal additional ablation duration post-pulmonary vein isolation (PVI) is crucial for successful atrial fibrillation (AF) treatment.

Purpose of the Study:

• To investigate the optimal additional ablation duration following acute PVI in patients with paroxysmal AF.
• To assess the impact of varying additional ablation durations on pulmonary vein reconnection and dormant conduction.

Main Methods:

• Patients with paroxysmal AF were randomized into three groups receiving 90, 120, or 150 seconds of additional ablation after acute PVI.
• The primary outcome was pulmonary vein reconnection or dormant conduction (DC) after a 30-minute waiting period.
• Follow-up included 24-hour Holter monitoring at 3, 6, and 12 months to assess freedom from AF.

Main Results:

• Increasing additional ablation duration from 90 to 150 seconds significantly decreased reconnection/DC rates (22% to 4%).
• Freedom from AF was comparable across groups (52-72%), but repeat procedures significantly decreased in the 150-second group (4% vs. 36%).
• Reconnection/DC was identified as the sole predictor of AF recurrence in multivariate analysis.

Conclusions:

• Prolonging cryoballoon ablation duration after achieving PVI effectively reduces pulmonary vein reconnection and the need for repeat procedures.
• An additional ablation duration of 150 seconds, within a time-to-isolation approach, appears most appropriate for optimizing PVI outcomes.
• While recurrence and complication rates were similar, the reduction in repeat procedures supports longer ablation times for improved long-term management.