Hyperkinetic heart in severe hypertension: a separate clinical hemodynamic entity.

A long-term study of established hypertension helped identify a well defined group of 10 patients who differed both clinically and hemodynamically from 59 patients with the more frequent form of this disease. Their cardiac output was significantly increased (P less than 0.001) despite a severe elevation of arterial pressure (average 212/125 mm Hg plus or minus 13.5/7.3[standard error[). All had labile hypertension of long standing (16.2 years average) that was difficult to control and always symptomatic; in all, the diagnosis of pheochromocytoma had to be specifically excluded. Increased myocardial contractility was suggested by (1) significant elevation of the rate of rise of isovolumic pressure (P less than 0.001), and (2) high ratio of cardiac output to cardiopulmonary volume (P less than 0.005). Beta adrenergic blockade with propranolol helped to alleviate symptoms and to control tachycardia but failed by itself to reduce arterial pressure.