Systemic and coronary hemodynamic and neurohumoral effects of levodopa in chronic congestive heart failure.

Systemic and neurohumoral effects of oral levodopa were evaluated in 17 patients with severe chronic heart failure. The maximum mean dopamine level achieved after 1.5 g of oral levodopa was 19.6 +/- 16.4 ng/ml. At peak dopamine level, cardiac index increased by 14% from baseline (1.95 +/- 0.55 to 2.27 +/- 0.45 liters/min/m2, p less than 0.05), stroke volume index increased by 14% (22.4 +/- 6.0 to 25.9 +/- 5.8 ml/min/m2, p less than 0.01). There was a trend toward reduced systemic vascular resistance of 13% (1,773 +/- 769 to 1,535 +/- 432 dynes.s.cm-5, p = 0.08). There was no significant change from baseline in heart rate, mean arterial pressure, right atrial pressure, pulmonary capillary wedge pressure, pulmonary vascular resistance and rate-pressure product. In addition, as the arterial dopamine level increased there was a concomitant decrease in plasma norepinephrine level that was sustained for the period of observation. In a subgroup of 8 patients, there was no change in coronary sinus blood flow, myocardial oxygen consumption, myocardial oxygen extraction, lactate extraction and transmyocardial release of catecholamines after levodopa. These findings suggest that oral levodopa, 1.5 g, can improve left ventricular function without adversely affecting myocardial energetics and catecholamine balance.