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.

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.

Silent Killer 

Approximately one fourth of all myocardial infarctions are silent, without chest pain or other symptoms.

Heart Attack vs. Cardiac Arrest

A heart attack is different from, but can be the cause of cardiac arrest, which is the stopping of the heartbeat, and cardiac arrhythmia, an abnormal heartbeat. It is also distinct from heart failure, in which the pumping action of the heart is impaired; severe myocardial infarction may lead to heart failure, but not necessarily.

Risk Factors and Statistics

AMI is a medical emergency, and the leading cause of death for both men and women all over the world.

Important risk factors include:

• a 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,
• smoking,
• excessive alcohol consumption,
  
• the abuse of certain drugs,
  
• high triglyceride levels,
  
• high LDL (low-density lipoprotein, "bad cholesterol")
  
• low HDL (high density lipoprotein, "good cholesterol"),
  
• diabetes,
  
• high blood pressure,
  
• obesity,
  
• chronically high levels of stress
• older age—especially men over 40 and women over 50,
  

Symptoms

Classical symptoms of acute myocardial infarction include:

• chest pain (typically radiating to the left arm or left side of the neck),
• shortness of breath,
• nausea,
• vomiting,
  
• palpitations,
  
• sweating, and
  
• anxiety (often described as a sense of impending doom).
  

Gender Differences

Women often experience different symptoms from men. The most common symptoms of MI in women include:

• shortness of breath,
  
• weakness, and
  
• fatigue.