Hemodynamic and cardiometabolic effects of prenalterol in patients with acute myocardial infarction and shock.

Five patients with acute myocardial infarction and shock were treated with a new, highly selective beta-1-adrenoreceptor agonist, prenalterol. After 1 and 2 mg of the drug, all patients had markedly increased blood pressure and cardiac output, but no changes in heart rate or systemic vascular resistance. Left- and right-sided filling pressures decreased in three of the patients. In two of the patients, however, the increase in contractility and afterload was followed by a marked increase in left- and right-sided filling pressures, and myocardial lactate uptake changes to lactate production. After addition of sodium nitroprusside, blood pressure and filling pressures returned towards normal, and myocardial lactate uptake was restored. As anticipated from the hemodyanamic findings, myocardial oxygen consumption increased after prenalterol. It is suggested that the potent inotropic agent prenalterol may be used with great caution in cardiogenic shock.