Amrinone and dobutamine in severe chronic heart failure

pp 268-274

Abstract

Amrinone and dobutamine are positive inotropic agents with beneficial hemodynamic effects in patients with congestive heart failure. We compare the effects of intravennous dobutamine and its association with amrinone in 8 patients with stable New York Heart Association class IV congestive heart failure, with cardiac index and pulmonary artery wedge pressure> 20 mmHg. All patients were studied in an intensive care unit with continuous hemodynamic and electrocardiographic monitoring. Dobutamine was administered initially at an infusion rate of 2.5  μg/kg/min and dose was increased until maximun increased in cardiac index or adverse effects occurred. Duration of administration was 8 hours, and after that amrinone was added with a bolus injection of 1 mg/kg followed by an infusion of 10  μg/kg/min for 12 hours. In response to dobutamine there was a significant increase in cardiac index, but these was significantly greater within the 4 hours than that seen at 8 hours. With addition of amrinone, cardiac index increased more than that seen with dobutamine alone. Both agents significantly decreased pulmonary artery wedge pressure, and systemic and pulmonary vascular resistance, compared with baseline levels. The present study shows that dobutamine had beneficial hemodynamics effects in patients with congestive heart failure, but with evidence of hemodynamic tolerance developing after 8 hours of infusion. Association with amrinone exerted a greater improve in ventricular performance and no attenuation of effects was seen after 12 hours of therapy. The positive inotropic action of amrinone may vary with the myocardial CAMP content and therefore should be enhanced after ß1 adrenergic stimulation. Heart rate remained unchanged, and no increases in ventricular ectopic activity was seen in this study.