COMPARATIVE EFFECTS OF DOBUTAMINE AND AMRINONE ON CORONARY BLOOD-FLOWIN PATIENTS WITH IDIOPATHIC DILATED CARDIOMYOPATHY

Although amrinone has favorable hemodynamic effects in patients with c ongestive heart failure, little is known about its effects on coronary blood flow (CBF). We compared the effects of intravenous low-dose dob utamine and amrinone on CBF in 10 patients with dilated cardiomyopathy using a Doppler guidewire. We infused dobutamine at a dose of 5 and 1 0 mu g/kg/min for 5 min. After the end of each stage, coronary flow ve locity (CFV) and coronary arterial diameter (CAD) in the proximal left anterior descending coronary artery, and hemodynamic variables were o btained. After the CFV and hemodynamics returned to baseline, we infus ed 1 mg/kg of amrinone over 5 min, and obtained these variables at 5 a nd 10 min after the cessation of the infusion. CAD did not increase wi th dobutamine, but significantly increased after amrinone (% increase: 10 +/- 7%; P < 0.001 vs. baseline). CFV progressively increased with dobutamine (5 mu g/kg/min: 21 +/- 26%; P < 0.05 vs. baseline; 10 mu g/ kg/min: 53 +/- 42%; P < 0.005 vs. baseline and 5 mu g/kg/min), but sli ghtly decreased after amrinone (-4 +/- 17%; P = not significant vs. ba seline). CBF increased during dobutamine (5 mu g/kg/min: 25 +/- 29%; P < 0.05; 10 mu g/kg/min: 66 +/- 55%; P < 0.005) and after amrinone (19 +/- 22%; P < 0.05) compared to that at baseline, Although there was a significant correlation between the percent increase in CFV and that in dP/dt during dobutamine infusion (r = 0.82, P < 0.001), this correl ation was not observed after amrinone (r = 0.23). In conclusion, altho ugh both agents significantly increased CBF in patients with dilated c ardiomyopathy, they do so by different mechanisms. Amrinone mainly inc reases CBF by causing dilatation of epicardial coronary arteries. Thes e results suggest that amrinone has beneficial effects on coronary flo w dynamics in dilated cardiomyopathy. (C) 1997 Wiley-Liss, Inc.