Introduction: Second-generation cryoballoon ablation is safe and effective in patients with paroxysmal atrial fibrillation (AF). Previous studies have found there to be high acute rates of pulmonary vein (PV) isolation with the Artic Front Advance catheter. Reaching a nadir temperature of -40° has also been shown to achieve electrical isolation of the pulmonary veins. The aim of this study is to report the long-term outcomes of paroxysmal AF patients who underwent cryoablation without concurrent electrical mapping.
Methods: 228 patients (mean age 66.7 ± 10.0) who underwent cryoablation without electrical mapping from January 2015 to April 2019 in Eastbourne District General Hospital were followed up for a mean duration of 26.8 ± 16.7 months. The primary endpoint was freedom from AF, atrial flutter, or atrial tachycardia ≥30s after a 90-day blanking period.
Results: The mean procedure and fluoroscopy time was 55.6 ± 12.1 and 10.7 ± 4.6 minutes respectively. The mean temperatures achieved in the PV were as follows: left upper -48.8° ± 6.0°, left lower -47.3° ± 5.6°, right upper -48.6° ± 6.2°, right lower -46.9° ± 5.4°, respectively. Freedom from atrial arrhythmia was achieved in 167 of 228 of patients (73.2%; Figure 1). The proportion of patients who were European Heart Rhythm Association (EHRA) class 1 increased from 0.9% at baseline to 53.5% at final follow up. Subsequently, 34 of 228 patients (14.9%) underwent a second radiofrequency ablation and only 1 patient had third radiofrequency ablation during the follow up period. Electrical reconnection was found at redo ablation in: 11 left upper PVs, 11 left lower PVs, 8 right upper PVs, and 15 right lower PVs.
Conclusion: Second-generation cryoablation without confirming pulmonary vein isolation using electrical mapping is effective resulting in a freedom from arrhythmia in the majority of patients in the long term. In addition, foregoing electrical mapping results in short procedure times, thus potentially increasing catheter lab capacity.