Complete Recovery of Thyrotoxicosis Cardiomyopathy After Antithyroid and Corticosteroid Therapy: A Case Report.

Thyroid storm (TS) is an extreme hypermetabolic state due to thyrotoxicosis. TS may manifest as cardiovascular symptoms, including atrial fibrillation (AF) (9 - 23%) and heart failure (HF). Dilated cardiomyopathy (DCM) and HF develop at a later stage in approximately 1% of thyrotoxicosis patients. A 46-year-old man presented to the emergency department with a chief complaint of severe dyspnea and rapid AF. Blood test examination showed overt thyrotoxicosis. The Burch-Wartofsky point scale is 60 (highly suggestive of TS). Echocardiography showed severely reduced left ventricular (LV) systolic function. The patient was diagnosed with TS, rapid AF with DCM, probably due to thyrotoxic cardiomyopathy. After 3 months of antithyroid therapy, corticosteroids, and optimal HF management, we observed complete recovery of his ventricular function, along with spontaneous conversion to sinus rhythm. LV systolic dysfunction is described in a small percentage of thyrotoxicosis patients. In later stages of thyrotoxicosis cardiomyopathy (TCM), HF phenotype of DCM will develop, characterized by progressive reduction of myocardial systolic function that marks advanced stages of TCM. This report highlighted the importance of thyroid investigation as an integral part of HF etiological work-up due to its reversibility.