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Myocardial Infarction

Diagram of a myocardial infarction

A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to a part of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which may travel into the shoulder, arm, back, neck, or jaw. Often it occurs in the center or left side of the chest and lasts for more than a few minutes. The discomfort may occasionally feel like heartburn. Other symptoms may include shortness of breath, nausea, feeling faint, a cold sweat, or feeling tired. About 30% of people have atypical symptoms, with women more likely than men to present atypically.

Pathophysiology

Illustration showing the blockage of a coronary artery

Myocardial infarction results from the interruption of blood supply to a part of the heart, causing heart cells to die. This is most commonly due to blockage of a coronary artery following the rupture of a vulnerable atherosclerotic plaque, an unstable collection of lipids and white blood cells in the wall of an artery. The resulting ischemia and oxygen shortage, if left untreated for a sufficient period of time, can cause damage or death (infarction) of heart muscle tissue (myocardium).

Symptoms

The classic symptoms of myocardial infarction include sudden chest pain (typically radiating to the left arm or left side of the neck), shortness of breath, nausea, vomiting, palpitations, sweating, and anxiety. Women may experience fewer typical symptoms than men, with more emphasis on shortness of breath, weakness, a feeling of indigestion, and fatigue.

Diagnosis

Diagnosis of myocardial infarction is based on the patient's history, physical examination, and electrocardiogram (ECG) findings. Blood tests are also used to detect markers of myocardial damage, such as troponin and creatine kinase.

Treatment

Immediate treatment for myocardial infarction includes administration of aspirin to prevent further blood clotting, and nitroglycerin to relieve chest pain. In cases of ST-elevation myocardial infarction (STEMI), reperfusion therapy is indicated, which may include percutaneous coronary intervention (PCI) or thrombolysis.

Prevention

Prevention of myocardial infarction involves lifestyle changes and management of risk factors. This includes maintaining a healthy diet, regular physical activity, smoking cessation, and controlling conditions such as hypertension, diabetes, and hyperlipidemia.

Related pages

• Coronary artery disease
• Cardiac arrest
• Heart failure
• Atherosclerosis