Differences of Atrial Electrophysiological Properties between Vagal and Sympathetic Type Atrial Fibrillations

Introduction: Autonomic modulation of cardiac activities plays an important role in the pathogenesis of atrial fibrillation (AF).The aim of this study was to assess the differences of atrial electrical/structural properties between the patients with vagal and sympathetic AF. Methods: The study included 16 patients (53±12 y/o, male 14)with frequent attacks of symptomatic paroxysmal AF. All cases underwent 24-hour ambulatory Holter monitoring before ablation. Onset of AF accompanied with increased HF component and decreased L/H ratio was designated as vagal AF (Group 1, n=8); whereas decreased HF component and increased L/H ratio was classified as sympathetic AF (Group 2, n=8).Electrical/structural properties were evaluated. Results: All patients had AF originating from PVs. There was a higher incidence of non-PV triggers in Group 2 patients than Group 1 (50%vs.0%, p=0.02). Group 1 had a higher bipolar peak-to-peak voltage of left atrium (LA), longer activation time and smaller LA volume than those of Group 2, whereas electrical and structural properties in the right atrium were similar. After a follow-up of 9±4 months, there was a lower incidence of AF recurrence in Group 1 than Group 2 (0%vs.50%, p=0.02). Conclusion: There is a better electrical property with smaller LA volume in the patients with vagal AF. The LA substrate is worse, and the coexisting non-PV triggers and recurrence following ablation are more prevalent in the patients with sympathetic AF.