THE ACUTE DOSE-RELATED EFFECTS OF ETHANOL ON RIGHT VENTRICULAR-FUNCTION IN ANESTHETIZED DOGS

The acute dose-related effects of small to moderate doses of ethanol on right ventricular functioning were studied on 18 anesthetized, artificially ventilated dogs in 39 sessions. Diluted ethanol (from 25-37.5%) was infused during 40 minutes, yielding total doses of 1.0 g/kg (n = 15), and 1.5 g/kg (n = 12) with corresponding venous blood ethanol peak concentrations of 1.38 +/- 0.25 and 2.41 +/- 0.31 mg/ml, respectively. Heart rate increased up to 16% in groups receiving ethanol. In the control group receiving the equivalent volume of saline (n = 12) heart rate decreased 14%. Pulmonary arterial systolic pressure increased from 24 +/- 3 to 27 +/- 3 mmHg and diastolic pressure from 11 +/- 2 to 14 +/- 4 mmHg (p < 0.05) when the ethanol dose was 1.0 g/kg. The pulmonary arterial resistance increased from 620 +/- 135 to 805 +/- 185 dyn.s.cm-5 (p < 0.01). The peak dP/dt decreased maximally by 20% with increasing ethanol doses. Stroke volume decreased maximally by 14% but due to the increase in heart rate, cardiac output even increased. The changes in end-diastolic volume and pressure were not significant. Hence, the ethanol increased heart rate and afterload of the right ventricle but depressed the myocardium.