Haemodynamic effects of isoprenaline in acute myocardial infarction.

The haemodynamic effects of isoprenaline were investigated in IO patients with acute myocardial infarction. Serial measurements of multiple parameters at increasing concentrations of the drug allowed establishment of a dose-response curve. Significant increase over basal values was observed in cardiac output, stroke volume, and dp/dt. Heart rate increased only moderately. Systemic and pulmonary vascular resistances diminished, without appreciable change in aortic or pulmonary mean pressures. These results were obtained with concentrations of 2/3 to tg/min. No arrhythmias were induced and the clinical tolerance was uniformly good. The use of these small doses of isoprenaline and their effectiveness in the management of myocardial failure complicating infarction are particularly emphasized.