Balloon warming time is the strongest predictor of late pulmonary vein electrical reconnection following cryoballoon ablation for atrial fibrillation

BACKGROUND Pulmonary vein isolation by cryoballoon ablation is an accepted method of treating atrial fibrillation. Little data exist regarding factors affecting late electrical reconnection of pulmonary veins following cryoballoon ablation. OBJECTIVE To investigate factors determining pulmonary vein reconnection in patients undergoing repeat catheter ablation for recurrent atrial fibrillation following cryoballoon ablation. METHODS Fifty-one consecutive patients undergoing repeat catheter ablation for recurrent atrial fibrillation following initial cryoballoon ablation underwent retrospective assessment of initial cryoablation characteristics, including balloon and vein sizes, venogram occlusion score, balloon freezing time from 0 to 30 degrees C, nadir temperature, and balloon warming time from -30 to +15 degrees C, recorded during the initial cryoballoon procedure. RESULTS Of 199 veins assessed, 91 had reconnected (1.8 per patient). Balloon warming time (odds ratio [OR] 3.21; 95% confidence interval [CI] 2.00-5.13; P < .0001), nadir temperature (OR 1.94; 95% CI 1.42-2.66; P < .0001), vein occlusion score (OR 1.74; 95010 CI 1.29-2.34; P = .0003), and balloon freezing time (OR 1.58; 95% CI 1.03-2.42; P = .037) predicted pulmonary vein reconnection. On multivariate analysis, balloon warming time (OR 3.71; 95% CI 2.2-6.24; P <= .0001), pulmonary vein size (OR 1.63; 95% CI 1.08-2.43; P = .020), and vein occlusion score (OR 1.48; 95% CI 1.06-2.08; P = .021) remained statistically significant independent predictors of pulmonary vein reconnection. The receiver operating characteristic for the multivariate model yielded an area under the curve of 0.82. CONCLUSIONS Balloon warming time, vein occlusion score, and pulmonary vein size predict pulmonary vein reconnection. Balloon warming time was the most important predictive factor, and the manipulation of balloon warming may be a novel therapeutic strategy for improving outcomes of cryoballoon ablation for atrial fibrillation.