The heart is the human body's hardest working organ. Throughout life it continuously pumps blood enriched with oxygen and vital nutrients through a network of arteries to all tissues of the body. To perform this strenuous task, the heart muscle itself needs a plentiful supply of oxygen-rich blood, provided through a network of coronary arteries. These arteries carry oxygen-rich blood to the heart's muscular walls (the myocardium).
A heart attack (myocardial infarction) occurs when blood flow to the heart muscle is blocked, and tissue death occurs from loss of oxygen, severely damaging a portion of the heart.
Acute coronary syndrome (ACS) is a severe and sudden heart condition that, although needing aggressive treatment, has not developed into a full blown heart attack. Acute coronary syndrome includes:
- Unstable Angina. Unstable angina is potentially serious and chest pain is persistent, but blood tests do not show markers for heart attack.
- NSTEMI (Non ST-segment Elevation Myocardial Infarction). This condition, also called non Q-wave myocardial infarction, is diagnosed when blood tests and ECGs indicate a heart attack that does not involve the full thickness of the heart muscle. The injury in the arteries is less severe than with a full-blown heart attack.
Patients diagnosed with acute coronary syndrome (ACS) may be at risk for a major heart attack. Doctors use a patient's medical history, various tests, and the presence of certain factors to help predict which ACS patients are most at risk for developing a more serious condition. The severity of chest pain itself does not necessarily indicate the actual damage in the heart.
Heart attack (myocardial infarction) is among the most serious outcome of atherosclerosis. It can occur as a result of one of two effects of atherosclerosis:
- If the plaque develops fissures or tears. Blood platelets adhere to the site to seal off the plaque, and a blood clot (thrombus) forms. A heart attack can then occur if the blood clot completely blocks the passage of oxygen-rich blood to the heart.
- If the artery becomes completely blocked after gradual buildup of plaque due to atherosclerosis. Heart attack may occur if not enough oxygen-rich blood can flow past the blockage.