CausesBy Mayo Clinic staff
Myocardial ischemia occurs when the blood flow through one or more of the blood vessels that lead to your heart (coronary arteries) is decreased. This decrease in blood flow leads to a decrease in the amount of oxygen your heart muscle (myocardium) receives. Myocardial ischemia may occur slowly as arteries become blocked over time, or it may occur quickly when an artery becomes blocked suddenly.
Conditions that may cause myocardial ischemia include:
- Coronary artery disease (atherosclerosis). Atherosclerosis occurs when plaques made of cholesterol and other cellular waste products build up on your artery walls and restrict blood flow. Atherosclerosis of the heart arteries is called coronary artery disease and is the most common cause of myocardial ischemia.
- Blood clot. The plaques that develop in atherosclerosis can rupture, causing a blood clot, which may lead to sudden, severe myocardial ischemia, resulting in a heart attack.
- Coronary artery spasm. A coronary artery spasm is a brief, temporary tightening (contraction) of the muscles in the artery wall. This can narrow and briefly decrease or even prevent blood flow to part of the heart muscle. Coronary artery spasms are more common in people with risk factors for heart disease, such as high cholesterol and high blood pressure, but the spasms can happen in people who have no risk factors, too. Coronary artery spasms can also occur in people who have conditions that affect their immune systems, such as lupus.
- Severe illnesses. Myocardial ischemia can occur when the metabolic demands of your heart increase or when blood pressure is very low due to infection, bleeding or other severe illness.
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