CK-3197 was developed as a selective positive inotropic agent for the treatment of congestive heart failure. We compared the hemodynamic and myocardial energetic effects of CK-3197 to ouabain in the pentobarbital-anesthetized dog. Fifteen minutes after intravenous (i.v.) administration of CK-3197 (0.1, 0.3, and 1.0 mg/kg) to five dogs, mean left ventricular (LV) dP/dt increased by 24, 68, and 109% and mean arterial pressure (MAP) decreased by 4, 9, and 18%, respectively, from basal values. CK-3197 was 11 times more potent as a positive inotropic agent than as a vasodilator. Heart rate (HR) increased by 5, 14, and 24% after these doses of CK-3197, whereas LV end diastolic pressure (LVEDP) decreased by 4 mm Hg after the highest dose of compound. LV oxygen consumption (MVO2) and stroke MVO2 increased by 9, 25, and 102% and 1, 8, and 58%, respectively, at the peak of the increases in LV dP/dt. Ouabain (0.02 and 0.03 mg/kg, i.v.) increased MAP (12 and 22%), HR (2 and 20%), and LV dP/dt (19 and 36%), with a 14 and 16% increase in LV MVO2 and a 12 and -6% change in stroke MVO2. Thus, CK-3197 is a selective, positive inotropic agent with preload reducing activity in the dog. CK-3197, similar to ouabain, produced energy-efficient positive inotropic responses with either no increase in MVO2 or increases in myocardial oxygen consumption that were less than the expected 1:1 ratio with LV dP/dt. Therefore, CK-3197 may have significant utility in the clinical treatment of congestive heart failure.
