CARDIOVASCULAR EFFECTS OF DOBUTAMINE

The cardiovascular effects of dobutamine, a derivative of dopamine have been investigated in seven patients with chronic left ventricular dysfunction. The patients were either suffering from coronary heart disease or from cardiomyopathy. Dobutamine was administered at doses of 2.5-5.0-7.5-10.0 and 15.0 μg/kg/min. The following parameters were measured: aortic pressure, left ventricular pressure (LVEDP, LVdp/dtmax) by using a Millar tip manometer, pulmonary artery pressure and cardiac output (dy-dilution technique). The positive chronotropic effect of dobutamine was small in the lower dosage range and reached significance only with the highest dose of 15.0 μg/kg/min. Systolic aortic pressure was increased moderately over the whole dosage range (p<0.05). However the increment of mean aortic pressure (+11 mm Hg), of stroke volume (+22%) and of stroke work (+49%) was already maximum (p<0.05) at a dose of 5.0 μg/kg/min. The positive inotropic action of dobutamine caused a dose related increase of cardiac index and of LVdp/dtmax of +53% and of +193% respectively. This effect was accompanied by a continuous and significant decrease of LVEDP and of peripheral resistance. Dobutamine induced arrhythmias have not been observed. 15 min after infusion stop, no dobutamine effect could be detected. These findings demonstrate that the actions of dobutamine are not merely cardioselective. However, in the dose range between 2.5 and 15.0 μg/kg/min a positive inotropic effect is predominant. Further clinical trials with dobutamine on patients with severe myocardial dysfunction and low output syndrome may yield promising results. © 1978 Springer-Verlag.