HEART ATTACK
DEFINITION |
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A heart attack is the death of, or damage to,
part of the heart muscle because the supply of blood to the heart
muscle is severely reduced or stopped. |
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Heart attack is the leading cause of death in the United States.
More than 1.5 million Americans suffer a heart attack every year,
and almost half a million die, according to the American Heart
Association. Most heart attacks are the end result of years of
silent but progressive coronary artery disease, which can be
prevented in many people. A heart attack is often the first symptom
of coronary artery disease. According to the American Heart
Association, 63% of women and 48% of men who died suddenly of
coronary artery disease had no previous symptoms. Heart attacks are
also called myocardial infarctions (MIs).
A heart attack occurs when one or more of the coronary arteries that
supply blood to the heart are completely blocked and blood to the
heart muscle is cut off. The blockage is usually caused by
atherosclerosis, the build-up of plaque in the artery walls, and/or
by a blood clot in a coronary artery. Sometimes, a healthy or
atherosclerotic coronary artery has a spasm and the blood flow to
part of the heart decreases or stops. Why this happens is unclear,
but it can result in a heart attack.
About half of all heart attack victims wait at least two hours
before seeking help. This increases their chance of sudden death or
being disabled. The longer the artery remains blocked during a heart
attack, the more damage will be done to the heart. If the blood
supply is cut-off severely or for a long time, muscle cells suffer
irreversible injury and die. The patient can die. That is why it is
important to recognize the signs of a heart attack and seek prompt
medical attention at the nearest hospital with 24-hour emergency
cardiac care.
About one fifth of all heart attacks are silent, that is, the victim
does not know one has occurred. Although the victim feels no pain,
silent heart attacks can still damage the heart.
The outcome of a heart attack also depends on where the blockage is,
whether the heart rhythm is disturbed, and whether another coronary
artery supplies blood to that part of the heart. Blockages in the
left coronary artery are usually more serious than in the right
coronary artery. Blockages that cause an arrhythmia, an irregular
heartbeat, can cause sudden death. |
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| HEART ATTACK RELATED ITEMS |
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