Blood pressure levels in acute myocardial infarction.

Serial blood pressure recordings were taken for 72 hours in 112 patients with acute myocardial infarction and in 96 patients with cardiac ischemia, admitted to hospital no more than 6 hours after the onset of chest pain. During the first hour of admission 66 (31.7%) had a blood pressure recorded 160/100 or greater. By the sixth hour, without specific antihypertensive therapy, this number had fallen to 13 (6.3%). This fall was subsequently maintained with very similar trends for both acute myocardial infarction and cardiac ischemia. Such an early blood pressure fall in acute myocardial infarction may indicate that this is too labile a measurement to determine the need for, or efficacy of, antihypertensive therapy aimed at the preservation of myocardium. The hospital course and mortality rate of patients with acute myocardial infarction and early hypertension, as defined, did not differ significantly from the non-hypertensive group.