Ethanol-induced coronary vasodilation in patients with and without coronary artery disease

To assess the influence of ethanol on coronary arterial blood flow and dimensions, we measured coronary sinus blood flow in 35 subjects (23 men and 12 women, aged 38 to 69 years; (29 with and 6 without coronary artery disease) before and during a 15- to 30-minute intracoronary infusion of (1) 5% dextrose in water (n=15, controls) or (2) 5% ethanol in 5% dextrose in water (n=20). In the controls heart rate, arterial pressure, and coronary sinus blood flow were unchanged. In those receiving ethanol at a rate that produced a concentration in coronary sinus blood of 285±102 (mean±SD) mg/dl, heart rate-systolic arterial pressure product was unchanged; coronary sinus blood flow rose 27±36%, and coronary vascular resistance fell 17±22% (p<0.05 in comparison to baseline); arterial-coronary sinus oxygen content difference fell (p<0.05), and epicardial coronary arterial dimensions were unchanged. Thus intracoronary ethanol increases coronary blood flow and decreases resistance without inducing a change in epicardial coronary dimensions, suggesting that its effect results from dilatation of the intramyocardial resistance vessels.