Effects of a twenty-four-hour milrinone infusion in patients with severe heart failure and cardiogenic shock as a function of the hemodynamic initial condition

The systemic and pulmonary arterial hemodynamics of 40 patients with severe congestive heart failure were determined during a 24-hour infusion of milrinone (0.5 μg/kg/min) after a loading dose of 50 μg/kg. A subgroup ( n = 18) with severe cardiac pump dysfunction and three patients in cardiogenic shock were analyzed separately; their hemodynamic response was compared with that of the total group ( n = 40). After 15 minutes of intravenous therapy with milrinone, the total group ( n = 40) showed an increase of 65% in cardiac index; in the subgroup ( n = 18) cardiac index increased by 94% after 15 minutes and by 106% after 30 minutes. Likewise, pulmonary capillary wedge pressure decreased after 30 minutes in both the total group ( n = 40) and the subgroup ( n = 18). The heart rate showed an overall tendency to decrease. The systolic blood pressure tended upward and remained statistically unchanged in the total group, whereas in the subgroup in which pressure was initially low, there was an increase in the systolic pressure after 1 hour and a further increase after 24 hours. Mean arterial pressure also rose in this subgroup. The early improvement in all measured hemodynamic parameters was sustained throughout the 24-hour infusion period. Development of tolerance was not observed, nor were any clinically symptomatic side effects or symptomatic arrhythmias. Thus intravenous milrinone is a safe medication for the rapid and prolonged improvement in hemodynamics, specifically in patients with severely restricted cardiac pumping function.