Alcohol-induced electrical remodeling: Effects of sustained short-term ethanol infusion on ion currents in rabbit atrium

Abstract

Background: In some patients, above-average alcohol consumption before occurrence of atrial fibrillation (AF) in terms of a "holiday heart syndrome" (HHS) can be determined. There is evidence that long before development of apparent alcohol-induced cardiomyopathy, above-average alcohol consumption generates an arrhythmogenic substrate which abets the onset of AF. Changes of atrial current densities in terms of an electrical remodeling after sustained short-term ethanol infusion in rabbits as a potential part of HHS pathophysiology were examined in this study. Methods: Rabbits of the ethanol group (EG) received sustained short-term intravenous alcohol infusion for 120 hours (during infusion period, blood alcohol level did not fall below 158 mg/dl), whereas NaCl 0.9% was infused in the placebo group (PG). Using patch clamp technique in whole-cell mode, atrial current densities were measured and compared between both groups. Results: Ethanol infusion did not alter current densities of Ito [58.7 ± 5.0 pA/pF (PG, n = 20 cells) vs. 53.9 ± 5.0 pA/pF (EG, n = 24)], Isus [11.3 ± 1.4 pA/pF (PG, n = 20) vs. 10.2 ± 1.0 pA/pF (EG, n = 24)], and IK1 [-1.6 ± 0.3 pA/pF (PG, n = 17) vs. -2.0 ± 0.3 pA/pF (EG, n = 22)]. However, alcohol infusion resulted in a remarkable reduction of ICa,L current densities [-28.4 ± 1.8 pA/pF (PG, n = 20) vs. -15.2 ± 1.4 pA/pF (EG, n = 22)] and INa [-75.4 ± 3.6 pA/pF (PG, n = 17) vs. -35.4 ± 4.4 pA/pF (EG, n = 21)], respectively. Conclusion: Sustained short-term ethanol infusion in rabbits alters atrial current densities. HHS might be favored by alcohol-induced atrial electrical remodeling. Copyright © 2009 by the Research Society on Alcoholism.