Background: The autonomic nervous system (ANS) is a potentially potent modulator of the initiation and perpetuation of atrial fibrillation (AF), whereas the presence of AF can activate and alter the ANS. The catheter ablation of AF (AFCA) may cause the cardiac ANS dysfunction, whereas restoration of sinus rhythm or sympathovagal imbalance by AFCA can reverse this process. Our principal goal was to investigate the short-term effect of AFCA on ANS functions evaluated by noninvasive chronotropic (CI), resting heart rate (RHR), and heart rate recovery (HRR) indices.
Method: A total of 45 patients were enrolled with symptomatic, drug refractory paroxysmal AF undergoing first cryoballoon (CB) pulmonary vein antrum isolation (PVAI) with one 28-mm CB using single 3-minute freeze techniques without bonus applications. All patients underwent symptom-limited exercise treadmill testing to evaluate noninvasive parameters of ANS before PVAI. For those patients who remained in sinus rhythm, an additional exercise test was repeated after 1 and 3 months after discharge.
Results: The autonomic CI and RHR/HRR indices were impaired after PVAI and persisted post-PVAI 3 months. However, these parameters were not different in patients with and without recurrence.
Conclusion: This study demonstrated that the successful AFCA might concurrently impair the ANS parameters. The autonomic imbalance between the sympathetic and parasympathetic activity after AFCA could either become antiarrhythmic and/or proarrhythmic based on which of the two components was going to prevail after successful AFCA. The impaired ANS balance after PVAI might also be another hypothetical mechanism for AF recurrence particularly in the absence of PV reconnection.
Keywords: atrial fibrillation; autonomic nervous system; cryoballoon; exercise stress testing; heart rate recovery; pulmonary vein isolation.
© 2017 Wiley Periodicals, Inc.