Left ventricular dysfunction of isolated working rat hearts after chronic alcohol consumption.

The mechanical, haemodynamic, and energetic functions of isolated perfused working hearts from chronic alcoholic and control rats were studied. Male Long-Evans rats were fed a nutritionally-complete liquid diet containing 38% of daily calories as ethanol (isocaloric replacement with dextrin-maltose for controls) for 34 to 48 weeks. Alcoholics and controls received either 7.4% (low-fat) or 21.0% (high-fat) of calories from lipid. Animals were matched by dry heart weight for comparisons and hearts were evaluated at a constant heart rate in an improved isolated ejecting heart perfusion preparation. Ventricular function curves and the response to 10(-7) mol . litre-1 dobutamine HCl were obtained during normoxic and hypoxic perfusion. In normoxia, the hearts from the high- and low-fat alcoholic animals exhibited a significantly lower response of left ventricular maximum systolic pressure, left ventricular maximum rate of pressure rise and maximum ejection velocity to dobutamine than did the controls. In hypoxia, the left ventricular maximum systolic pressure of the low-fat alcoholic hearts was slightly, but significantly, lower than that of the low-fat control hearts at the three filling pressures studied. Also in hypoxia, the increase in left ventricular maximum rate of pressure rise with dobutamine was significantly less in the alcoholic hearts than in controls. These data suggest that long-term consumption of moderate amounts of alcohol even along with a nutritionally-adequate diet can result in depressed myocardial contractility and pump function that may be manifest when the heart is subjected to stress conditions.