Endocrine Abstracts

Introduction: Hyperthyroidism-associated myocardial infarction with normal epicardial coronary arteries on angiogram is seldom reported.

Case report: A 61-year-old Caucasian man, resident in an iodine sufficient area, presented with chest pain in the emergency unit. ECG revealed inferolateral myocardial infarction with ST-segment elevation. Soon after admission, the patients developed collapse due to primary ventricular fibrillation, requiring defibrillation. Coronary angiogram revealed normal epicardial vessels. These findings suggest that the acute myocardial ischemia was secondary to coronary vasospasm. Biochemical data showed hypokalemia (K+=3 mmol/l) and elevated TT₄ (18.26 μg/dl). After cardiac stabilization and kallium repletion, the patient was referred for endocrine assessment. Severe hyperthyroidism was confirmed (TSH <0.03 mUI/l, FT₄=47.5 pmol/l, TT3=352 ng/dl). TPO antibodies were slightly increased (48 IU/ml). Thyroid ultrasound revealed small diffuse goiter. Antithyroid therapy was started (Methimazole 45→30→20→15 mg/day). Despite iodine overload via coronary angiography, normalization of FT₄ levels (11.2 pmol/l) was noticed seven weeks later. The patient did not repeat angina, arrhythmic events or hypokalemia after normalization of thyroid function.

Conclusion: This case highlights the importance of considering hyperthyroidism in cases of myocardial infarction with normal epicardial coronary arteries. We suggest thyroid function screening in patients with coronary spasm.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.