Myocardial infarction (MI), or heart attack, is a frightening event that leads to permanent cardiac damage or may cause sudden death. Myocardial infarction takes place when partial or total blockage of the coronary arteries occurs. A cardiac muscle that no longer receives the necessary quantity of oxygen-rich blood from an artery suffers damage when its cells become oxygen-deprived and die. The larger the area in which oxygen is absent, the more severe the infarction.

 According to the American Heart Association, in 2001, more than one million Americans suffered a heart attack or cardiac arrest. More than 40% of those who suffered coronary damage during the year died.

 There any many causes of MI, but the main cause is arterial blockage  followed by coronary spasm and various cardiac problems. But a heart attack is not always preceded by prior cardiovascular complaints in a patient. The majority of causes can be traced to an unhealthy lifestyle (smoking, lack of exercise, being overweight, stress, eating a high-fat diet, incurable diseases like arterial hypertension or diabetes) or due to factors related to sex, age or heredity. 

Symptoms such as pain in the left arm, in the neck, in the jaw or between the shoulder blades are very similar to those of angina pectoris but they do not tend do subside spontaneously, even after the administration or anti-angina drugs. Chest pain may also occur while at rest and last over 20 minutes.