Causes of Myocardial Infarction

Myocardial infarction (MI) is myocardial necrosis caused by acute, sustained ischemia and hypoxia of the coronary arteries. Clinically, it typically presents with severe, prolonged retrosternal pain that is not fully relieved by rest or nitrate medications. It is accompanied by elevated serum cardiac enzyme levels and progressive electrocardiographic changes. Complications may include arrhythmias, shock, or heart failure, and the condition can often be life-threatening.

Causes of Myocardial Infarction

1. Excessive Fatigue

Excessively strenuous physical labor—especially activities involving heavy lifting while climbing stairs—or intense sports activity and prolonged periods of mental or physical stress can significantly increase cardiac workload and abruptly raise myocardial oxygen demand. In patients with coronary artery disease (CAD), pre-existing coronary artery atherosclerosis and stenosis prevent adequate vasodilation, resulting in myocardial ischemia. Intense physical exertion may also trigger plaque rupture, leading to acute myocardial infarction.

2. Overeating

Consuming large amounts of high-fat, high-calorie foods causes an abrupt rise in blood lipid concentrations, increasing blood viscosity and platelet aggregability. This may lead to thrombus formation on top of pre-existing coronary artery stenosis, precipitating acute myocardial infarction.

3. Cold Exposure

Sudden cold exposure may trigger acute myocardial infarction. Therefore, patients with coronary artery disease must take special care to stay warm. The cold seasons of winter and early spring represent one of the higher-risk periods for acute myocardial infarction.

4. Smoking and Heavy Alcohol Consumption

Smoking and excessive alcohol intake can provoke coronary artery spasm and increase myocardial oxygen consumption, thereby triggering acute myocardial infarction.

5. Constipation

Constipation is highly prevalent among elderly individuals. Clinically, cases of myocardial infarction triggered by straining during defecation are not uncommon in older adults. Elderly individuals must pay sufficient attention to this issue and maintain regular, unstrained bowel movements.

6. Severe Hemorrhage and Shock

During shock, severely low blood pressure compromises coronary perfusion. Moreover, massive hemorrhage imposes significant physiological stress, inducing profound biochemical alterations that may precipitate myocardial infarction.

The above outlines the major causes of myocardial infarction. We hope this information proves helpful to you.