Predictors of cardiac neuromodulation achieved by cryoballoon ablation performed in patients with atrial fibrillation who were in sinus rhythm before the ablation.

BACKGROUND: The impact of pulmonary vein isolation (PVI) performed with cryoballoon (CB) on the intrinsic cardiac autonomic nervous system (ICANS) remains unclear. OBJECTIVE: The purpose of this study was to evaluate the predictors and the clinical meaning of cardiac neuromodulation achieved by CB-ablation as assessed by sinus heart rate (HR) response after the procedure. METHODS: Patients who underwent CB-ablation for drug-resistant atrial fibrillation (AF) from January 2014 to October 2018 were included. Twelve­leads rest ECG was taken both before and after the procedure. After discharge, patients were scheduled for follow-up visits at 1, 3, 6, and 12 months and 24 h Holter recordings were obtained at each follow-up visit. All documented AF episodes of >30 s were considered as recurrence. RESULTS: Four-hundred seventy-two patients (62.3% male, age 56.7 ± 13.6 years, 97.2% paroxysmal AF) were included. Mean HR before the procedure was 60.17 ± 10.4 bpm, while the morning after the procedure mean HR was 75.48 ± 12.0 bpm. Age at enrollment (R = -0.26; p < 0.001), baseline HR before the CB-A (R = -0.32; p < 0.001), nadir temperature in each right pulmonary vein (R = -0.11, p = 0.022; R = -0.16; p = 0.001) were significantly associated with the ∆HR. At 2-year follow-up, freedom from recurrences was 83.1% for the patients with HR increase ≥15 bpm after CB-A and 66.3% in patients with HR increase ˂15 bpm (p = 0.021). CONCLUSION: Sinus HR increase is a frequent phenomenon after CB-A, that can be predicted by both clinical and procedural factors and that correlates with better outcome after cryo-PVI.