Haemodynamic effects of a new inotropic agent (dobutamine) in chronic cardiac failure

The haemodynamic effects of dobutamine were studied in 14 patients with chronic congestive cardiac failure. Heart rate, central venous, pulmonary arterial, pulmonary wedge, and aortic pressures, aortic dp/dt, cardiac output, cardiac index, stroke volume, and pulmonary and systemic vascular resistances were measured or derived. Dose-response curves were obtained by recording all measurements before and after intravenous infusion of dobutamine at rates of 2.5, 5, and 10 mug/kg per min for periods of 30 minutes each. Significant increases in mean values were observed for cardiac output from 3.7 to 6.4 l/min (82%), for stroke volume from 44 to 64 ml (39%), and aortic dp/dt from 692 to 1414 mmHg/s (92.0 to 188.1 kPa/s (76%). Heart rate increased only moderately from 86 to 101 per minute (31%). Significant reduction occurred in pulmonary wedge and central venous pressures. Mean aortic and pulmonary pressures did not change significantly, as a measure of decreased vascular resistances. The drug was uniformly well tolerated. The predominant inotropic effects of dobutamine without tachycardia or arrhythmias may be valuable in severe heart failure.