Novel beta-blocker pretreatment prevents alcohol-induced atrial fibrillation in a rat model

BACKGROUND: A case report published in 2019 described a patient who presented with difficult-to-manage atrial fibrillation (AF) that consistently was associated with alcohol consumption. After the patient did not respond to drug therapy, a novel beta-blocker (BB) pretreatment regimen initiated immediately before alcohol consumption successfully prevented AF occurrence. OBJECTIVE: The purpose of this study was to test the hypothesis that a novel prophylactic BB therapy given before alcohol consumption could prevent AF in a rat model. METHODS: An alcohol-induced AF model was developed in adult Sprague-Dawley rats of both sexes by administering alcohol (2 g/kg intraperitoneal [IP]) once every other day for a total of 4 times. Three groups were enrolled: alcohol (EtOH; n = 10); alcohol plus BB (metoprolol 50 mg/kg IP) pretreatment (EtOH+BB; n = 10); and control (n = 9). Cardiac function (assessed by echocardiography and left ventricular hemodynamics) and in vivo atrial electrophysiology and AF inducibility tests were performed 24 hours after the last injection. RESULTS: All but 1 rat completed the study. Alcohol exposure did not significantly impact cardiac function and the atrial effective refractory period. However, alcohol exposure significantly increased AF inducibility [median (first and third quartile [Q1–Q3]) 0% (0%–0%) in control vs 60% (25%–100%) in the EtOH group; P <.05] and AF duration [0 second (0–0 second) in control vs 0.81 second (0.24–3.67 seconds) in the EtOH group; P <.05]. Compared to the EtOH group, the EtOH+BB group had significantly reduced AF inducibility [0% (0%–22.5%); P <.05] and duration [0 second (0–0.2 second); P <.05]. CONCLUSION: Metoprolol pretreatment before alcohol administration significantly decreased AF induction in rats. These findings suggest that BB pretreatment is a promising prophylaxis regimen for alcohol-induced AF.