The course of the disease of six cases with pheochromocytoma was analyzed in patients, aged from 19 to 65, with manifestations mainly of the cardiovascular system. The diagnosis was verified in five of them at necropsy and in one of them--intraoperatively. The arterial hypertension accompanied by distinct vegetative symptomatics were the basic clinical signs and in some of the cases--disturbances in the carbohydrate metabolism. In four patients the arterial hypertension was permanent, in two of them--with paroxysmal elevation opresf blood pressure. In the other two--with hypertonic crises on the background normal blood pressure. The duration of the hypertension--from a single hypertonic crisis during pheochromocytoma attack, had a lethal end, till the fifth year. In three of the patients rhythm disorders (supraventricular tachycardia or tachyarrhythmia) originated in a pheochromocytoma paroxysm and in three--acute left ventricular insufficiency (gallop rhythm, pulmonary edema). The clinical picture resembles heart defect, myocardial infarction with congestive cardiac insufficiency and rhythm disorders, renal insufficiency with symptomatic arterial hypertension and decompensated hypertonic heart, epilepsy, coggagenosis . The authors admit that the development of acute left ventricular failure in hypertonic patients, that could hardly be explained only by the increase of the heart afterloading (in advanced age, not enlarged and no data about grve heart lesions) or the origination of severe rhythm disorders, not coped by the modern antirhythm agents, are signs, indicating, the existence of pheochromocytoma. The catecholamine affection of myocardium, that was found in three of the deceased patients, very likely, contributes to the origination of left ventricular failure.