Background: Vagal nerve response, seen during cryoballoon ablation of the pulmonary veins, can be attributed to the ablation’s effect on the ganglionated plexi. This effect is demonstrated with drops in blood pressure and heart rate during pulmonary vein isolation with cryoballoon ablation.

Purpose: To evaluate surrogate markers for vagal response during pulmonary vein isolation with cryoballoon ablation.

Methods: A total of 22 patients with paroxysmal atrial fibrillation underwent pulmonary vein isolation with a 28-mm second-generation cryoballoon using a 3-minute freeze technique. Two or more lesions were performed for each vein. Initial blood pressure, nadir blood pressure, time to reach -30 degrees, time to reach -40 degrees, time from start of thaw to reach zero degrees (TT0), time from start of thaw to the nadir blood pressure (TTNBP), total freeze time, minimal temperature reached, and time from start of freeze to vein isolation by electrogram were recorded. Clustered data for each vein were analyzed using the common slope and linear intercept mixed model.

Results: All patients (mean age: 62.5 ± 8.4 years; male sex: 69%, body mass index: 31.7 ± 5.7; mean CHA2 DS2 -VASc score: 1.8 ± 1.2; white race: 100%; hypertension: 56%; coronary artery disease: 38%; sleep apnea: 50%; mean left atrial volume index: 58.6 ± 17.8 ml/m2 ; left ventricular ejection fraction of ≥55: 100%) had paroxysmal atrial fibrillation. Univariate analysis demonstrated that the best surrogate marker for vagal response was the TT0 in the inferior veins. The drop in blood pressure increased up to fourfold, with a onefold increase in thawing duration (TT0 in left inferior vein: 3.040, P

Conclusion: Vagal response during cryoballoon ablation was seen mainly during isolation of the inferior pulmonary veins.