Depression of Myocardial Contractility with Low Doses of Ethanol in Normal Man

Abstract

Depression of myocardial contractility after ethanol ingestion in man has previously been shown only in patients with heart disease. In the present study, normal subjects, aged 23-30 years, ingested six ounces of 43% alcohol over a two hour period (Group I, 6 subjects) or a one hour period (Group II, 5 subjects). Systolic time intervals were measured every 15 min from simultaneous ECG, phonocardiogram and carotid pulse tracings. Heart rate, total electromechanical systole and left ventricular ejection time (LVET) were not changed at any time from pre-alcohol values and, except for a small (5 mm Hg) and transient change in diastolic pressure in Group II, aortic pressures also were unchanged. However, in Group I, after 60 min, at a blood ethanol of 74 ± 3 mg%, left ventricular depression was manifested by increased pre-ejection period (PEP) from 90 ± 2 to 96 ± 3.1 msec, isovolumic time (IVT) from 44 ± 3.5 to 52 ± 4 ( P < .01), and PEP/LVET ratio from 0.299 ± 0.009 to 0.323 ± 0.01 ( P < .05). Further depression occurred at two hours with blood ethanol at 111 ± 6 mg%. Doubling ingestion rate (Group II) produced reduction of left ventricular performance at 30 min at a blood level of 50 ± 3 mg%. Feeding of isocaloric sucrose in 5 subjects (Group III) as a control produced a decrease in PEP, IVT, and PEP/LVET. Thus, alcohol in nonintoxicating doses elicits a depression of cardiovascular function in normal unhabituated subjects.