[Acute effects of ethanol on the performance and metabolism of the isolated working heart, both normal and failing].

The direct effects of ethanol on cardiac contractility are controversial, probably because of methodological reasons in relation to the choice of appropriate experimental models. We studied the direct effects of 1, 2, 5 and 10 g/l ethanol on myocardial performance and metabolism in the isolated perfused working guinea-pig heart. In the normal heart ethanol induced a dose-dependent, fully reversible depression of cardiac contractility without significant changes of heart rate or cardiac metabolism. In the post-anoxic failing heart this effect was more pronounced. Ethanol had no arrhythmogenic effect even at high concentrations. Finally, it had no measurable effect on anoxic-induced alterations or post-anoxic recovery after a period of 20 minutes of anoxic perfusion. However anoxic-induced lactate production was decreased in hearts pretreated with 10 g/l ethanol. These results demonstrate the direct negative inotropic effect and the lack of chronotropic effect of ethanol. They suggest the lack of effect on excitability. The mechanism of the negative inotropic effect does not seem to be metabolically related since cardiac oxygen consumption and lactate production remained unaltered.