The cardiovascular effects of the continuous infusion of dobutamine in patients with severe cardiac failure.

Twenty-five patients with left ventricular failure and low cardiac output received a 72 hour infusion of dobutamine (10-15 microgram/kg/min) in order to determine the cardiovascular properties of this new inotropic agent. Left ventricular contractile performance improved significantly during the infusion as measured by systolic time intervals and echocardiographic parameters. Mean PEP/LVET decreased from 0.76 +/- 0.03 to 0.58 +/- 0.03 (P less than 0.05). The percent change in internal dimension of the left ventricle from diastole to systole increased from 9.5 +/- 1 to 16.8 +/- 1 (P less than 0.05) and Vcf increased from 0.47 +/- 0.05 to 0.80 +/- 0.06 circ/sec (P less than 0.05). Mean cardiac output (nine patients) rose from 1.97 +/- 0.15 to 3.33 +/- 0.50 L/min/m2 while mean pulmonary capillary wedge pressure fell from 28 +/- 3 to 18 +/- 2 mm Hg during the infusion period (both P less than 0.05). These changes in cardiac function occurred without significant changes in heart rate, ventricular irritability, or blood pressure. Urine flow and urine sodium concentration increased during the infusion period. The improvement of cardiac function without the simultaneous development or exacerbation of undesirable effects (tachycardia, premature ventricular contractions, increased pulmonary or systemic resistance, tachyphylaxis, etc.) makes dobutamine a highly desirable inotropic agent.