Ethanol, infused either intravenously or directly into the coronary arteries of open-chest dogs, produced progressive alterations in left ventricular end-diastolic pressure, enddiastolic volume, end-systolic volume, and ejection fraction. Despite gross visible impairment of left ventricular contractility, there was no change in cardiac output, heart rate, left ventricular systolic pressure, or left ventricular dp/dt. Gradations of myocardial damage were seen with electron microscopy, which indicate that the mitochondria appear to be the most vulnerable organelle.