CHARACTERISTICS OF SYSTOLIC-TIME INTERVALS IN PATIENTS WITH PHEOCHROMOCYTOMA

The effect of chronic catecholamine excess on cardiac function was assessed in 8 patients with surgically proven pheochromocytoma and the results compared with data obtained from normal controls and essential hypertensives. Major findings in systolic time intervals (STI) in patients with pheochromocytoma were a marked shortening of electromechanical systole and left ventricular ejection time (ET), but pre-ejection period (PEP) remained within normal limits. These findings were not altered by correction for heart rate. The ET/PEP ratio was very low (1.87 +/- 0.31) due to the remarkable shortening of ET. The ET/PEP ratio in essential hypertensives was also low (1.77 +/- 0.38), but this was mainly due to a remarkable prolongation of PEP. Low cardiac index, low stroke index and high total peripheral resistance index were preoperative characteristics in patients with pheochromocytoma, but returned to normal after operation. These results suggest that chronic excessive production of catecholamines from pheochromocytoma has deleterious effects on the heart, and that wide differences in STI exist between patients with pheochromocytoma and those with essential hypertension.