Introduction: Anti-influenza drug oseltamivir has been reported to suppress atrial fibrillation (Af) in vitro; however, since information of oseltamivir is lacking regarding in vivo anti-Af property, we studied it using the paroxysmal Af canine model.
Methods: Oseltamivir in doses of 3 and 30 mg/kg/10 min was intravenously infused to the isoflurane-anesthetized, chronic atrioventricular block dogs (n=4) under monitoring electrophysiological variables, in which Af was induced by 10 s of burst pacing on atrial septum.
Results: The high dose of oseltamivir decreased sinoatrial/idioventricular rate and mean blood pressure, whereas no significant change was observed by its low dose. Oseltamivir delayed inter-atrial conduction in dose- and frequency-dependent manners, whereas it prolonged atrial effective refractory period in dose-dependent but frequency-independent manners. The high dose prolonged ventricular effective refractory period, which was not detected by the low dose. Oseltamivir decreased Af incidence and shortened Af duration in a dose-dependent manner along with prolongation of Af cycle length.
Conclusion: Oseltamivir effectively suppressed the inducibility of paroxysmal Af and shortened its duration in vivo, which may depend on the delay in inter-atrial conduction and prolongation of atrial effective refractory period.