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 I(to) [58.7 +/- 5.0 pA/pF (PG, n = 20 cells) vs. 53.9 +/- 5.0 pA/pF (EG, n = 24)], I(sus) [11.3 +/- 1.4 pA/pF (PG, n = 20) vs. 10.2 +/- 1.0 pA/pF (EG, n = 24)], and I(K1) [-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 I(Ca,L) current densities [-28.4 +/- 1.8 pA/pF (PG, n = 20) vs. -15.2 +/- 1.4 pA/pF (EG, n = 22)] and I(Na) [-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.