A total of 17 patients with angiographically proven coronary artery disease and at least one stenosis blocking 70% of the left anterior descending or circumflex artery were included in a double-blind, randomized study. They received either 5 mg carvedilol or 6 mg propranolol intravenously. Heart rate, aortic pressure, mean coronary sinus pressure and coronary flow (thermodilution) were measured and coronary resistance and the rate-pressure product were calculated before and 25 min after injection. Carvedilol significantly (P < 0.05)="" lowered="" the="" heart="" rate="" (mean,="" 76="" to="" 69="" beats/min),="" aortic="" pressure="" (mean,="" 153/80–135/72="" mmhg),="" rate-pressure="" product="" (mean,="" 117–93="" mmhg/min),="" and="" coronary="" flow="" (mean,="" 114–94="" ml/min).="" coronary="" resistance="" (mean,="" 0.97–1.07="" mmhg="" ×="" min/ml)="" and="" coronary="" flow="" related="" to="" the="" rate-pressure="" product="" (mean,="" 1.0–1.02="" ml/mm="" hg)="" showed="" no="" significant="" change="" after="" carvedilol="" treatment.="" propranolol="" lowered="" the="" heart="" rate="" (mean,="">P < 0.05)="" and="" rate-pressure="" product="" (mean,="" 109–96="" mm.="" hg/min;="" not="" significant).="" aortic="" pressure="" (mean,="" 145/72–147/74="" mmhg),="" coronary="" flow="" (mean="" 109–101="" ml/min),="" coronary="" resistance="" (mean,="" 1.1–1.2="" mmhg="" ×="" min/ml),="" and="" coronary="" flow="" related="" to="" the="" rate-pressure="" product="" (mean,1.12–1.19="" ml/mmhg)="" showed="" no="" significant="" change="" after="" propranolol="" administration.="" following="" single="" application,="" carvedilol="" lowered="" the="" rate-pressure="" product="" more="" markedly="" than="" did="" propranolol="" on="" account="" of="" its="" acute="" blood-pressure-lowering="" effect.="" no="" differences="" in="" the="" hemodynamic="" effects="" of="" carvedilol="" and="" propranolol="" were="" found.="" neither="" drug="" seems="" to="" influence="" the="" adaption="" of="" coronary="" flow="" to="" myocardial="" oxygen="">