Myocardial infarction is the irreversible death of heart muscle due to prolonged lack of the oxygen supply. Approximately 1.5 million cases of myocardial infarction occur annually in the United States. There are three types of myocardial infarctions: ST-segment Elevation Myocardial Infarction, or STEMI, Non-ST segment Elevation Myocardial Infarction, or NSTEMI, and coronary spasm, or unstable angina. The term ST-segment refers to the pattern that appears on an electrocardiogram. Both STEMI and NSTEMI can cause enough damage to be considered major heart attacks. STEMI is the most common type of myocardial infarction.

1. What Is Acute Myocardial Infarction?

Also known as a heart attack, a myocardial infarction occurs when blood flow to a part of the heart either decreases or stops, causing damage to the heart muscle. The word acute means to be severe or intense. A heart attack can be anywhere from minor to severe. No matter how mild, it is still recommended you seek medical attention right away.