A 50 year old female presented unusual electrocardiographic changes including AV block, accelerated idioventricular rhythm, ventricular premature systole with severe fluctuation of blood pressure and clinical features of angina pectoris. Deep ST segment depression was demonstrated in spite of the normal coronary arteriogram and the negative coronary artery spasm study. Urinary excretion of catecholamines and their metabolites were elevated and a huge pheochromocytoma was found in the left adrenal glandd. After removal of the pheochromocytoma, the electrocardiographic abnormalities and the blood pressure were normalized and teh aptient became asymptomatic.