[en] An analysis of clinical, electrocardiographic, roentgenological and biochemical changes was made in 170 patients with esophageal carcinoma before, during and after radiation therapy conducted by a continuous (34 patients) and split course (136 patients). A rise in sinus tachycardia, appearance of extrasystolia and His' bundle right branch block, lowering of the ST-segment, flattening or appearance of negative T wave, an increase in the activity of creatine phosphokinase and aspartate aminotransferase in the blood serum were noted in a number of patients during radiation therapy. The changes were observed more often and were more marked in patients who had received continuous telegammatherapy. Irrespective of the method of radiotherapy in the restoration of the processes of excitation and conduction, improvement of metabolism in the cardiac muscle, a decrease in dysproteinemia, an increase in the content of electrolytes in the blood were noted