title: Dobutamine and hydralazine: comparative influences of positive inotropy and vasodilation on coronary blood flow and myocardial energetics in nonischemic congestive heart failure.
abstract: Coronary blood flow and myocardial energetics were assessed after the administration of a parenteral inotrope (dobutamine hydrochloride) and an oral vasodilator agent (hydralazine) in 10 patients with nonischemic congestive heart failure. Dobutamine (5 micrograms/kg per min) and hydralazine (1 mg/kg) when group-matched elicited an identical increase in cardiac index and stroke volume index. Both agents augmented coronary blood flow while reducing coronary vascular resistance. Both forms of therapy elicited a significant increase in myocardial oxygen consumption. Dobutamine, demonstrating a balanced effect on the coronary circulation, induced a proportional increase in coronary blood flow and myocardial oxygen consumption, with the arterial-venous oxygen difference across the coronary vascular bed remaining unchanged. Hydralazine enhanced the myocardial oxygen supply versus demand ratio; despite a significant increase in myocardial oxygen consumption, the arterial-venous oxygen difference and the myocardial extraction ratio diminished. Both forms of therapy enhanced cardiac performance without inducing any electrocardiographic or clinical evidence of ischemia. Dobutamine, a positive inotropic agent, elicited a balanced effect on the coronary circulation while hydralazine, a vasodilator agent, induced a greater increase in coronary flow than in myocardial oxygen demand.
mesh_terms: D000328:Adult; D002395:Catecholamines / Q000627:therapeutic use*; D003326:Coronary Circulation; D004280:Dobutamine / Q000627:therapeutic use*; D005260:Female; D006333:Heart Failure / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology; D006439:Hemodynamics; D006801:Humans; D006830:Hydralazine / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D009206:Myocardium / Q000378:metabolism; D010101:Oxygen Consumption; D013268:Stimulation, Chemical; D014664:Vasodilation
chemical_list: D002395:Catecholamines; D006830:Hydralazine; D004280:Dobutamine