Controlled, eight-hour haemodynamic study of a sustained-release formulation of isosorbide dinitrate in moderate left ventricular failure.

The aim of the study was to assess the duration of the haemodynamic effects of a new sustained-release oral formulation of isosorbide dinitrate (ISDN). Twenty patients (17 men and 3 women; mean age 60 years) with acute myocardial infarction (10 anterior, 10 inferior) complicated by moderate left ventricular failure took part in a randomized controlled trial. Ten patients were randomly assigned to the placebo group and 10 to the ISDN group, who received 40 mg sustained release isosorbide dinitrate. Haemodynamic variables were measured before treatment, after 0.5 and 1 h and then every 2 hours up to the 8th hour after treatment. There was no significant change in any haemodynamic parameter in the placebo group, during the study period. In the ISDN group there was a significant fall in pulmonary artery diastolic pressure at 4 and 8 h, from 19.0 +/- 1.0 mm Hg to 16.5 +/- 1.2 mm Hg and 15.5 +/- 0.8 mmHg, respectively. The mean pulmonary capillary wedge pressure fell progressively from 17.9 +/- 1.0 to 12.5 +/- 1.2 mmHg at 2 h (p less than 0.001 in comparison with the placebo group. The fall remained significant up to 8 h. There was no statistically significant change in heart rate, cardiac index, systemic blood pressure or systemic and pulmonary vascular resistances. On the whole the cardiac index remained unchanged. There were numerous individual variations of cardiac index in relation to the initial mean pulmonary capillary wedge pressure and the magnitude of its fall following administration of ISDN. The change in cardiac index was inversely correlated with the control cardiac index (r = -0.69, p less than 0.02).