Association of Antiarrhythmic Drug Therapy With Syncope and Pacemaker Implantation in Patients With Atrial Fibrillation

Background: Early rhythm control therapy mainly with antiarrhythmic drugs (AADs) for new-onset atrial fibrillation (AF) reduces major adverse cardiovascular events. However, negative dromotropic effects of AADs via ion channel blocking may cause bradyarrhythmias. Objectives: This study aimed to evaluate the association between AAD use and the risk of pacemaker implantation or syncope in patients with new-onset AF receiving early rhythm control therapy with AADs. Methods: This study was based on data from the Korean National Health Insurance Service system. We screened all new-onset AF diagnoses that occurred from 2013 to 2019 and identified patients who were prescribed AADs within 1 year of AF diagnosis. The risk of pacemaker implantation or syncope was compared between AAD users and nonusers. Results: A total of 770,977 new-onset AF cases were identified and 142,141 patients were prescribed AADs. After multivariate adjustment, use of AADs was associated with 3.5-, 2.0-, and 5.0-fold increased risk of pacemaker implantation or syncope, syncope, and pacemaker implantation, respectively. Propensity score–matched analysis revealed similar results, demonstrating a significant association between AAD use and the risk of pacemaker implantation or syncope. This association was consistent across various subgroups. Women were more susceptible to adverse effects of AADs than men. Conclusions: This study showed an association between AADs and risk of pacemaker implantation or syncope, a consistent finding across various subgroups. Precise evaluation of such risk should be undertaken before prescription of AADs.