Introduction:
Hyperthyroidism is a condition in which there is an increased secretion of thyroid hormones that exceeds the current needs of the body. Increased concentrations of hormones affect proper functioning of many organs and systems, including the cardiovascular system. Untreated hyperthyroidism may result in myocardial infarction (MI), which very rarely is its first clinical manifestation.

Aim:
The aim of this work is to present the case of a male patient with no previous symptoms, in whom ST segment elevation myocardial infarction (STEMI) occurred as the first clinical manifestation of hyperthyroidism.

Case study:
Presentation and analysis of the case of a 41-year-old male admitted with clinical and electrocardiographic features of anterior wall STEMI in the course of hyperthyroidism.

Results and discussion:
The cause of ischemia and MI in patients with no previous coronary artery disease is not fully known. Probable predisposing factors may include increased serum thyroid hormone concentrations. It enhances the vasoconstrictor effect of catecholamines and hyperkinetic circulation, which may be the potential causes of ischemia. In addition, it predisposes to a hypercoagulable state, which is the cause of coronary thrombosis.

Conclusions:
It is not only high cholesterol levels and anemia that are the possible causes of MI. Endocrine disorders, such as hyperthyroidism should always be taken into account.