Myocardial infarction

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Myocardial infarction ( Infarctus myocardii, MI) or acute myocardial infarction (AMI) is the medical term for an event commonly known as a heart attack. It happens when blood stops flowing properly to part of the heart and the heart muscle is injured due to not receiving enough oxygen. Usually this is because one of the coronary arteries that supplies blood to the heart develops a blockage due to an unstable buildup of white blood cells, cholesterol and fat. The event is called "acute" if it is sudden and serious.

A person having an acute myocardial infarction usually has sudden chest pain that is felt behind the breast bone and sometimes travels to the left arm or the left side of the neck. Additionally, the person may have shortness of breath, sweating, nausea, vomiting, abnormal heartbeats, and anxiety. Women experience fewer of these symptoms than men, but usually have shortness of breath, weakness, a feeling of indigestion, and fatigue. In many cases, in some estimates as high as 64 percent, the person does not have chest pain or other symptoms. These are called "silent" myocardial infarctions.

Important risk factors are previous cardiovascular disease, old age, tobacco smoking, high blood levels of certain lipids (low-density lipoprotein cholesterol, triglycerides) and low levels of high density lipoprotein (HDL) cholesterol, diabetes, high blood pressure, lack of physical activity, obesity, chronic kidney disease, excessive alcohol consumption, the use of cocaine and amphetamines, and chronic high stress levels. The two main ways to determine if a person has had a myocardial infarction are electrocardiograms (ECGs) that trace the electrical signals in the heart and testing the blood for substances associated with damage to the heart muscle. Common blood tests are creatine kinase (CK-MB) and troponin. ECG testing is used to differentiate between two types of myocardial infarctions based on the shape of the tracing. When the ST section of the tracing is higher than the baseline it is called an ST-elevation myocardial infarction (STEMI) which usually requires more aggressive treatment.

Immediate treatments for a suspected myocardial infarction include aspirin, which prevents further blood from clotting, and sometimes nitroglycerin to treat chest pain and oxygen.[6] STEMI is treated by restoring circulation to the heart, called reperfusion therapy, and typical methods are angioplasty, where the arteries are pushed open, and thrombolysis, where the blockage is removed using medications. Non-ST elevation myocardial infarction (NSTEMI) may be managed with medication, although angioplasty may be required if the person is considered to be at high risk.[8] People who have multiple blockages of their coronary arteries, particularly if they also have diabetes, may also be treated with bypass surgery (CABG) Ischemic heart disease, which includes myocardial infarction, angina and heart failure when it happens after myocardial infarction, was the leading cause of death for both men and women worldwide in 2011