THE TREATMENT OF EUTHYROID CARDIAC PATIENTS WITH INTRACTABLE ANGINA PECTORIS AND CONGESTIVE FAILURE WITH RADIOACTIVE IODINE*†

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Abstract
The therapeutic results of hypothyroidism induced by radioactive iodine (I131) in 23 euthyroid patients with intractable angina pectoris or congestive failure are reported. The duration of observation after induction of hypothyroidism varied from 3-22 mos. and averaged 15.5 mos. In 6 additional patients treated with therapeutic doses, the period of observation has been too short for evaluation, and hypothyroidism has not yet developed. Persistent hypothyroidism can be regularly induced by 1 or more appropriate doses of I131. No radiation sickness and no toxic effects on the blood or kidneys were observed. There was no thyroiditis in 10 patients; mild or moderate transitory thyroiditis in 18, and severe thyroiditis in 1. Temporary mild hyperthyroidism occurred in 2 patients. Each patient received orally a total of from 25.5-176 millicuries of I131 in single or divided doses. The largest single dose was 56 millicuries. The avg. total dose was 61 millicuries. In 8 patients studied, the radiation delivered to the thyroid gland was 28,800-56,100 R.E.P. In 3 patients, hypothyroidism was induced in from 9-14 weeks with 28,800-43,700 R.E.P. Angina pectoris was strikingly lessened or abolished in 11 of the 17 patients with intractable cardiac pain. Several patients were rehabilitated and are gainfully employed. Concomitant congestive failure, present in several of these patients, was likewise improved. In the other 6 of the 17 patients, angina pectoris was relieved when the patients were myxedematous, but recurred when desiccated thyroid was administered in order to ameliorate the discomfort of myxedema. 4 of 6 patients, incapacitated primarily because of congestive heart failure, showed worthwhile improvement; in 3 of these the improvement was striking. In the clinical management of these patients, we have attempted to maintain the lowest metabolic rate consistent with the comfort of the patient and have administered small doses of desiccated thyroid after the induction of myxedema.