Background: Catheter ablation of atrial fibrillation is recommended for patients with symptomaticparoxysmal atrial fibrillation (PAF) despite anti-arrhythmic drugs (AADs). Radiofrequency ablation is widely accepted as an effective treatment for PAF. Cryoenergy by cryoballoon technique is an alternative to radiofrequency (RF) ablation. Cryoballoon ablation is safe, andhas a similar success rate in comparison to RF ablation. AF recurrence with cryoballoon ablationis roughly 30%. The aim of this study is to determine the predictors of AF recurrenceafter cryoballoon ablation.

Methods and Results: Sixty one patients with symptomatic PAF despite AADs withoutstructural heart disease were included. Cryoballoon ablation was performed in 60 patients (36 males, mean age: 54.6 ± 10.7, mean left atrium size: 3.74 ± 0.39 mm). Transthoracic echocardiography including tissue Doppler imaging was performed in all subjects during sinusrhythm at baseline and after the ablation. Intra-atrial and inter-atrial electromechanical delays,and PA-lateral were measured. All patients were scheduled for 24 h Holter recording at baselineand at 3, 6, 9 months follow-up. Venous samples were collected to measure CK-MB, Troponin-T (TnT), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) levels at baseline and 24 h after ablation. Median follow up was 10 (8–12) months. Forty eight (80%) patients were insinus rhythm during the follow up. In receiver operating curve (ROC) analysis, intraleft atrial electromechanical delay and PA-lateral achieve an area under the curve (AUC) 0.97 (p < 0.001) and 0.69 (p < 0.001) for the ability to predict AF recurrence. A cut-off value for baseline intra left atrial electromechanical delay of 29.5 ms predicted AF recurrence with sensitivity of 85% andspecifity of 98%. A cut-off value for PA-lateral of 125 ms predicted AF recurrence with sensitivity of 80% and specifity of 90%. In ROC analysis, age achieves an AUC 0.822 (p = 0.006) for theability to predict AF recurrence. A cut-off value for age of 64 predicted AF recurrence with sensitivity of 71% and specifity of 90%. Early recurrence of AF (HR = 60, 95% CI 18.61–417.86, p < 0.001) predicted also late recurrence of AF.

Conclusions: The increase in AF recurrence by increased intraleft atrial electromechanical delay, PA-lateral and older age show the importance of substrate in AF mechanism. Early recurrence was the strongest predictor of late recurrence of AF; therefore, existence of blankingperiod for cryoballoon ablation should be questioned.