Acute Myocardial Infarction

Acute myocardial infarction (AMI or MI), more commonly known as a heart attack, is a medical condition that occurs when the blood supply to a part of the heart is interrupted, most commonly due to rupture of a vulnerable plaque. The resulting ischemia or oxygen shortage causes damage and potential death of heart tissue. It is a medical emergency, and the leading cause of death for both men and women all over the world.

Important risk factors are a previous history of vascular disease such as atherosclerotic coronary heart disease and/or angina, a previous heart attack or stroke, any previous episodes of abnormal heart rhythms or syncope, older age—especially men over 40 and women over 50, smoking, excessive alcohol consumption, the abuse of certain drugs, high triglyceride levels, high LDL ("Low-density lipoprotein") and low HDL ("High density lipoprotein"), diabetes, high blood pressure, obesity, and chronically high levels of stress in certain persons.

The term myocardial infarction is derived from myocardium (the heart muscle) and infarction (tissue death due to oxygen starvation). The phrase "heart attack" is sometimes used incorrectly to describe sudden cardiac death, which may or may not be the result of acute myocardial infarction.

Classical symptoms of acute myocardial infarction include chest pain (typically radiating to the left arm), shortness of breath, nausea, vomiting, palpitations, sweating, and anxiety. Patients frequently feel suddenly ill. Women often experience different symptoms from men. The most common symptoms of MI in women include shortness of breath, weakness, and fatigue. Approximately one third of all myocardial infarctions are silent, without chest pain or other symptoms.

Immediate treatment for suspected acute myocardial infarction includes oxygen, aspirin, glyceryl trinitrate and pain relief, usually morphine sulfate. The patient will receive a number of diagnostic tests, such as an electrocardiogram (ECG, EKG), a chest X-ray and blood tests to detect elevated creatine kinase or troponin levels (these are chemical markers released by damaged tissues, especially the myocardium). Further treatment may include either medications to break down blood clots that block the blood flow to the heart, or mechanically restoring the flow by dilatation or bypass surgery of the blocked coronary artery. Coronary care unit admission allows rapid and safe treatment of complications such as abnormal heart rhythms.