Fenoldopam, a selective DA1-receptor agonist, infused intravenously fo
r 24 hours (0.6 +/- 0.3 mug/kg/min, range 0.1-1.5) in 25 patients with
NYHA functional class III or IV heart failure, produced a prompt and
sustained hemodynamic response. Cardiac index rose from an average pre
infusion baseline value of 1.8 to 2.6/l min. Stroke volume index incre
ased from 19 to 26 ml/m2 and stroke work index increased from 18 to 25
g m/m2. These changes were accompanied by a reduction in systemic vas
cular resistance from an average of 2400 to 1500 dynes sec/cm.5 There
was no change in the heart rate or right atrial pressure. There was a
transient reduction in the left ventricular filling pressure from 25 t
o 20 mmHg. Urinary sodium excretion did not change significantly. Tran
sient asymptomatic thrombocytopenia developed in four patients. The dr
ug was well tolerated by all patients. These results suggest that cont
inuous intravenous infusion of fenoldopam is safe and produces favorab
le hemodynamic responses in severe heart failure. However, unlike its
effects in patients with hypertension, it failed to produce sustained
natriuresis in these patients.