Isosorbide-5-mononitrate in the treatment of acute left ventricular failure following acute myocardial infarction.

Eleven patients with acute left ventricular failure following acute myocardial infarction (mean pulmonary capillary wedge pressure [PCW] greater than 20 mmHg) were entered into an open, haemodynamic study of oral isosorbide-5-mononitrate (ISMN). Left ventricular failure was resistant to intravenous diuretic therapy. No patient received concurrent cardioactive drugs nor further diuretic therapy during the study period. Haemodynamic data were acquired via a flow-directed thermodilution catheter placed in the pulmonary artery. Baseline data were acquired prior to the intravenous administration of an ISMN challenge. Thereafter, oral ISMN (20 mg, 8 hourly) was administered over 48 h. Following intravenous ISMN challenge, mean PCW fell from 26.2 to 17.5 mmHg. Cardiac index fell from 2.4 to 2.3 l/min/m2 due to a fall in heart rate (103 to 96.8 beats/min) as stroke volume and blood pressure were unchanged. At 8 h following ISMN, two patients were withdrawn due to hypotension (systolic pressure less than 85 mmHg). In the remainder, PCW remained acceptable throughout 48 h (13.1 mmHg at 48 h), cardiac output, systemic blood pressure and heart rate showed no further significant change. These data suggest that ISMN is effective in the treatment of acute left ventricular failure following acute myocardial infarction.