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 ventricular 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. Afterload reduction with isosorbide combined with inotropic stimulation with dopamine may produce greater improvement in left ventricular performance in patients with congestive cardiac failure than either drug alone. Such treatment should be used with caution possibly in patients whose left ventricular filling pressure falls into the lower range after isosorbide alone.