Cardiac effects of moderate thyrotoxicosis and their changes after surgical treatment of toxic goiter

Abstract

Introduction. To date, only few studies have been conductedon influence of surgical treatment of patients with toxic goiter on thyrotoxic structural and functional changes in the heart, tolerance to exercise and func­tional class of heart failure. The aim of the study was to examine the influence of surgical treatment of toxic goiter with moderate thyrotoxicosis on the patients’tolerance of physical activity, structural and functional changes in the heart, and severity of cardiac disorders. Material and methods. The studyincluded 97 pa­­tients with toxic goiter of different etiology. The subjects of the study were changes in functional class of heart failure, tolerance to physical activity, structural and functional disorders of the myocardium,cardiac rhythm abnormalities, and general condition. For this purpose, the results of the tests one year after thyroi­dectomy were compared with the data obtained after the achi­evement of euthyroid stateaspreparation for surgery. Patients underwent hormonal tests (TSH, T4 free, Anti-TPOAb, NT-pro-BNP), daily Holter monitoring, echo­cardiography, and six-minute walk test. For sta­­tistical analysis, parametric and nonparametric met­hods were used.The significance of difference between the samples was estimated by the Mann-Whitney U-criterion. Results and discussion. It was found that in 67 patients (69.1 %) had physical activity improved.Also in these patients, functional class of heart failure was improved, cardiac rhythm disorders were not deter­mined, systolic and diastolic functions of the heart were restored. In 28 (28.8 %) patients, improvement of the general condition was noted, tolerance to physical activity slightly increased, and functional class of heart failure did not change. In 2 (2.1 %) cases, general condition, cardiac disorders, structural-functional ab­­nor­malities of heart and the functional class of heart failure remained unchanged. Conclusions. Surgical treatment of patients with moderate thyrotoxicosis allows restoring physical activity and normalize cardiac activityin 2/3 of cases. The reason of the inferior rehabilitation of patients after surgical treatment is the irreversible structural changes in the myocardium that arose as a result of unreasonably extended and insufficiently effective drug treatment of toxic goiter and thyrotoxicosis. The severity of long-term results of surgical treatment worsens with the increase in the duration of drug treatment for patients with thyrotoxicosis.