Use of Phentolamine in Acute Myocardial Infarction Associated with Hypertension and Left Ventricular Failure

In 11 patients with hypertension associated with acute myocardial infarction intravenous phentolamine decreased the elevated left ventricular filling pressure. Cardiac index increased with a small decrease in arterial pressure, and therefore the same or increased stroke work was achieved at a lower filling pressure. In patients with acute hypertension myocardial oxygen demand was decreased and this may tend to increase infarct size. The potentially beneficial effects were less great in patients with chronic hypertension antedating the myocardial infarction.