FIELD: medicine, and, more particularly, endocrinology. SUBSTANCE: method involves using infrared thermography and permits avoiding side reactions of the cardiovascular system of the patient, probable in veloergometric test with proportioned stepped load as a criterion of differential diagnosis of myocardium affection in patients suffering from thyrotoxicosis. Investigation includes clinical electrocardiography and examination of patient's arms on infrared thermograph. Thermoasymmetry of arms with temperature difference of 0.5 C (left arm colder) permits diagnosing ischemia in the patient suffering from thyrotoxicosis with any type of changes in ECG including focal changes of myocardium. In absence of thermoasymmetry of arms the diagnosis is thyrotoxic dystrophy of myocardium. EFFECT: lower traumatism. 2 tbl
