Final answer:
A myocardial infarction (heart attack) occurs when blood flow is blocked to the heart, leading to damage and death of cardiac tissue. Symptoms often include chest pain and pressure, but some heart attacks may be asymptomatic. Complete blockage of a coronary artery is a common cause of a heart attack.
Step-by-step explanation:
A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow stops to a part of the heart causing damage to the heart muscle and the death of myocardial cells. An MI usually occurs because of complete blockage of a coronary artery, often due to a blood clot or the rupture of a plaque. An MI typically causes chest pain and pressure, among other possible symptoms, but at least one-quarter of MIs do not cause any symptoms.