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.
Also called myocardial infarctions, heart attacks are the leading cause of death in the United States. Each year, more than 1.5 million Americans suffer an attack, and almost half a million die. Most heart attacks follow years of silent but progressive coronary artery disease, which can be prevented in manypeople. 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 die suddenly of coronary artery disease had no previous symptoms.
A heart attack occurs when one or more of the coronary arteries that supply blood to the heart is completely blocked, cutting off blood to the heart muscle. The blockage is usually caused by atherosclerosis, the build-up of plaquein 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 seekinghelp. This increases their chance of sudden death or being disabled. 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 patient does not know one has occurred. Although the patient feels no pain, silent heart attacks can still damage the heart.
Major risk factors significantly increase the risk of coronary artery disease. Those which cannot be changed are:
- Heredity. People whose parents have coronary artery disease are more likely to develop it. African Americans are also at increased risk, due to their higher rate of severe high blood pressure.
- Sex. Men under the age of 60 years of age are more likely to have heart attacks than women of the same age.
- Age. Men over the age of 45 and women over the age of 55 are considered at risk. Older people (thoseover 65) are more likely to die of a heart attack. Older women are twice aslikely to die within a few weeks of a heart attack as a man.
Major risk factors which can be changed are:
- Smoking. It greatly increases both the chance of developing coronary artery disease and the chance of dying from it. Second-hand smoke may also increase risk.
- Highcholesterol from eating foods such as meat, eggs, and other animal products.
- High blood pressure. High blood pressure makes the heart work harder, and over time, weakens it, increasing the risk of heart attack, stroke, kidney failure , and congestive heart failure. When combined with obesity, smoking, high cholesterol, or diabetes, the risk of heart attack orstroke increases several times.
- Lack of physical activity. Even modest physical activity is beneficial if done regularly.
Contributing risk factors have been linked to coronary artery disease, but their significance and prevalence are not known yet. Contributing risk factorsare:
- Diabetes mellitus. More than 80% of diabetics die of some type ofheart or blood vessel disease.
- Obesity. Excess weight increases thestrain on the heart and increases the risk of developing coronary artery disease, even if no other risk factors are present. Obesity increases both bloodpressure and blood cholesterol, and can lead to diabetes.
- Stress and anger. Stress, the mental and physical reaction to life's irritations and challenges, increases the heart rate and blood pressure, and can injure the lining of the arteries. Evidence shows that anger increases the risk of dying from heart disease and more than doubles the risk of having a heart attack right after an episode of anger.
More than 60% of heart attack victims experience symptoms before the attack,sometimes days or weeks before. Sometimes people do not recognize the symptoms of a heart attack or are in denial that they are having one. Symptoms are:
- Uncomfortable pressure, fullness, squeezing, or pain in the center ofthe chest. This lasts more than a few minutes, or may go away and return.
- Pain that spreads to the shoulders, neck, or arms.
- Chest discomfort accompanied by lightheadedness, fainting, sweating, nausea, or shortness of breath.
All of these symptoms do not occur with every heart attack. Sometimes, symptoms disappear and then reappear. A person with any of these symptoms should immediately call an emergency rescue service or be driven to the nearest hospital with a 24-hour cardiac care unit, whichever is quicker.
Experienced emergency care personnel can usually diagnose a heart attack simply by looking at the patient. To confirm this diagnosis, they talk with the patient, check heart rate and blood pressure, perform an electrocardiogram, and take a blood sample.
Heart attacks are treated with cardiopulmonary resuscitation (CPR) when necessary to start and keep the patient breathing and his heart beating. Additional treatment can include close monitoring, electric shock, drug therapy, re-vascularization procedures, coronary artery bypass surgery, or repair ofblood vessels using a tiny plastic tube tipped with a balloon that compresses the plaque and opens the blocked artery (angioplasty).
The aftermath of a heart attack is often severe. Two-thirds of heart attack patients never recover fully. Within one year, 27% of men and 44% of women die. Within six years, 23% of men and 31% of women have another heart attack, 13% of men and 6% of women experience sudden death, and about 20% have heart failure. People who survive a heart attack have a chance of sudden death four to six times greater than others and a chance of illness and death two to ninetimes greater. Older women are more likely than men to die within a few weeks of a heart attack.
Many heart attacks can be prevented through a healthy lifestyle including eating right (foods that are low in fat, especially saturated fat; low in cholesterol; and high in fiber; plenty of fruits and vegetables; and limited sodium), regular exercise, maintaining a healthy weight, no smoking, moderate drinking, no illegal drugs, controlling hypertension, and managing stress.
Daily aspirin therapy may help prevent blood clots associated with atherosclerosis. It can also prevent heart attacks from recurring, prevent heartattacks from being fatal, and lower the risk of strokes.