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


CONCLUSIONS
Sustained short-term ethanol infusion in rabbits alters atrial current densities. HHS might be favored by alcohol-induced atrial electrical remodeling.
Laszlo
Roman
R
Department of Cardiology, University of Tuebingen, Tuebingen, Germany. roman.laszlo@med.uni-tuebingen.de
Eick
Christian
C
Schwiebert
Mareike
M
Schreiner
Birgit
B
Weig
Hans-Joerg
HJ
Weretka
Slawomir
S
Bosch
Ralph F
RF
Schreieck
Juergen
J
D000818:Animals; D020746:Calcium Channels, L-Type / Q000187:drug effects; D002469:Cell Separation; D002492:Central Nervous System Depressants / Q000494:pharmacology*; D015536:Down-Regulation / Q000187:drug effects; D004594:Electrophysiology; D000431:Ethanol / Q000494:pharmacology*; D006321:Heart / Q000187:drug effects*; D006325:Heart Atria; D066298:In Vitro Techniques; D007262:Infusions, Intravenous; D007473:Ion Channels / Q000187:drug effects*; D008564:Membrane Potentials / Q000187:drug effects; D009206:Myocardium / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000187:drug effects; D011817:Rabbits; D015222:Sodium Channels / Q000187:drug effects; D020257:Ventricular Remodeling / Q000187:drug effects
D020746:Calcium Channels, L-Type; D002492:Central Nervous System Depressants; D007473:Ion Channels; D015221:Potassium Channels; D015222:Sodium Channels; D000431:Ethanol