Enhancement by isosorbide dinitrate of haemodynamic effects of dopamine in chronic congestive cardiac failure.

The haemodynamic effects of dopamine and isosorbide dinitrate alone and in combination were studied in 8 patients with chronic congestive cardiac failure. In 7 patients dopamine, 6,tg/kg per min, increased mean cardiac index from 2-0 to 3 0 1/min per m2 (P < 0.0005); mean stroke volume index from 20 to 27 ml/m2 (P < 0.0025), and mean left ventricular stroke work index from 14 to 20 g M/M2 (P < 0.0025). Mean left ventricular filling pressure did not change significantly. Isosorbide, 5 to 10 mg sublingually, reduced mean left ventricular filling pressure from 29 to 24 mmHg (P < 0.0005) and mean arterial pressure from 80 to 73 mmHg (P < 0 01), with no significant change in mean cardiac index, stroke volume index, or left ventricular stroke work index. When dopamine was reinfused after isosorbide administration mean cardiac index increased to 3 2 1/min per m2, stroke volume index to 31 mu/m2 (P < 0 05 vs dopamine alone), and left ventricular stroke work index to 23 g in/m2 (P < 0-0125 vs dopamine alone). Mean left ventricular filling pressure rose slightly to 25 mmHg but this was significantly less than for dopamine alone (P < 0 0005). In an eighth patient, whose left ventri- cular filling pressure fell to 12 mmHg after isosorbide, the reinfusion of dopamine was associated with severe bradycardia and hypotension, which responded to the intravenous administration of atropine.