Effect of ethanol on the electrophysiological characteristics of pulmonary vein cardiomyocytes

Ethanol consumption has been considered to contribute to the occurrences of paroxysmal atrial fibrillation. Pulmonary veins are known to initiate atrial fibrillation. This study investigated whether ethanol may induce atrial fibrillation through increasing arrhythmogenic activity of pulmonary vein cardiomyocytes. Using the whole-cell clamp technique, the action potential and ionic currents were investigated in rabbit single pulmonary vein beating cardiomyocytes with and without (control) incubation of ethanol. Compared with control cardiomyocytes, pulmonary vein cardiomyocytes receiving 0.3 mg/ml or 1 mg/ml ethanol had shorter action potential duration, but had similar beating rates (2.6±1.3, 2.7±1.2, 2.7±1.2 Hz) and incidences (45%, 41%, 32%) of delayed afterdepolarization. Pulmonary vein cardiomyocytes receiving ethanol had smaller L-type Ca²⁺ currents and larger transient outward currents, but had similar transient inward, delayed rectified outward, inward rectified and pacemaker currents. These results suggest that ethanol has no direct effect on the arrhythmogenic potential of pulmonary vein cardiomyocytes.