The effects of combined administration of low-dose amrinone (100 mg) and hydralazine (75-100 mg) on resting hemodynamics and exercise capacity were studied in nine patients with severe congestive heart failure. Five patients were in New York Heart Association (NYHA) functional class IV and four were in class III. Cardiac index increased from 1.92 ± 0.36 l/min/m2 (mean ± SD) to 3.23 ± 0.63 l/min/m2 (p < 0.001); pulmonary wedge pressure decreased from 23.6 ± 4.1 to 15.1 ± 4.7 mm Hg (p < 0.001) and systemic vascular resistance from 1666 ± 210 to 1063 ± 189 dyn-sec-cm-5 (p < 0.001). Mean arterial pressure and heart rate were not significantly changed. The onset of action ranged from 30-150 minutes and the duration of action from 4-6 hours after oral administration. When compared with amrinone alone (100 mg) or hydralazine alone (75-100 mg), the increase in stroke volume index and the decrease in pulmonary wedge pressure induced by the combined therapy were significantly greater (p < 0.01). The hemodynamics benefits at rest were associated with an improvement in NYHA functional class in all but one patient during chronic therapy. Exercise capacity (Naughton protocol) increased during the first week of therapy from 6.1 ± 4.3 to 10.6 ± 5.3 minutes (p < 0.01). This increase in exercise capacity was sustained or further improved at 3 weeks. Thus, the hemodynamic effects of low-dose amrinone can be amplified by simultaneous administration of a vasodilator such as hydralazine in patients with severe congestive heart failure. This combined therapy results in a substantial and sustained improvement in functional class and exercise capacity.
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine
- Physiology (medical)