Heart Attack (Myocardial Infarction)
Heart Attack: Symptoms and Remedies
Heart Attack (Myocardial Infarction)
A heart attack, also known as a myocardial infarction, is a medical emergency that occurs when a portion of the heart is deprived of oxygen because of blockage of one of the coronary arteries, which supply the heart muscle (myocardium) with blood. Lack of oxygen causes characteristic chest pain and death of myocardial tissue.
Heart attacks are more likely to occur when arteries have already been substantially narrowed by years of coronary heart disease. Plaque (composed of cholesterol-rich fatty deposits, collagen and other proteins, and excess smooth muscle cells) builds up in the arterial walls, a process known as atherosclerosis. Arterial walls thicken and narrow, inhibiting the flow of blood into the heart.
When arterial walls have been roughened by plaque deposits, it becomes much easier for blood clots to form along the surface of the plaque. If the clots grow, or if they detach from their place of origin and are carried along to a narrower section of artery, they may block a coronary artery completely, causing a heart attack. Arteries may also narrow suddenly as a result of an arterial spasm.
One-third of all heart attacks occur with no prior warning signs. In the remainder, attacks of chest pain (angina) brought about by stress or exertion occur periodically for months or years prior to a heart attack. In some cases a mild heart attack produces no symptoms—a so-called silent heart attack.
Prompt emergency medical attention is crucial: If treatment is received within a few hours of the onset of a heart attack, chances for survival are good. Improved treatment methods—including the administration of thrombolytic (clot dissolving) drugs and angioplasty (inflation of a tiny balloon at the site of the blockage to widen the artery and permit the flow of blood through the artery)—have led to a steady decrease in mortality from heart attacks.
However, the best treatment remains prevention. The process of atherosclerosis may be halted or even reversed with fairly simple measures, and the risk of heart attack can thus be reduced.
- Chest pain or pressure, tightness, squeezing, burning, aching, or heaviness in the chest, lasting longer than 10 minutes. The pain or discomfort is usually located in the center of the chest just under the breastbone and may radiate down the arm (especially the left), up into the neck, or along the jaw line.
- Shortness of breath.
- Profuse sweating.
- Muscle weakness.
- Nausea and vomiting.
- A choking sensation.
- Anxiety, or a feeling of impending doom.
- No symptoms occur with a silent heart attack.
- Blood clots that block a coronary artery are the most common cause of heart attacks. Clots develop on plaque in a coronary artery. Pieces of a clot may also be carried along the coronary artery and cause an obstruction.
- Severely narrowed arteries due to atherosclerosis underlie the development of a heart attack.
- Cigarette smoking, high blood pressure, high blood cholesterol levels, a diet rich in saturated fat (especially animal fat), obesity, lack of exercise, and diabetes mellitus all promote atherosclerosis and thus increase the risk of heart attacks.
- A family history of early or premature heart attacks (before the age of 55 in men and 65 in women) increases the risk of heart attack.
- Men have a significantly higher risk of heart attack than premenopausal women. But the risk for postmenopausal women approaches that of men as estrogen production decreases with menopause.
- Risk increases with age: Heart attacks are most common after age 65.
- A spasm of the muscles of the arterial walls may cause a heart attack by narrowing an artery. Spasms may be triggered by smoking, extreme emotional stress, or exposure to very cold air or water.
- Abuse of cocaine or amphetamines may cause a sudden heart attack even in those with no signs of heart disease.
- Heavy exertion, such as shoveling snow or carrying heavy objects up stairs, and severe emotional stress may trigger a heart attack.
- Having had one heart attack increases the risk of future heart attacks.
- Don’t smoke. Your doctor may recommend methods for quitting, including nicotine replacement.
- Eat a diet low in fat, cholesterol, and salt.
- See your doctor regularly for blood pressure and cholesterol monitoring.
- Pursue a program of moderate, regular aerobic exercise. People over age 50 who have led a sedentary lifestyle should check with a doctor before beginning an exercise program.
- Lose weight if you are overweight.
- Your doctor may advise you to take a low dose of aspirin regularly. Aspirin reduces the tendency for the blood to clot, thereby decreasing the risk of heart attack. However, such a regimen should only be initiated under a doctor’s expressed recommendation.
- Patient history and physical examination are needed. Diagnosis will often be made immediately by a doctor or emergency response technician.
- An electrocardiogram (ECG) will be performed. This test measures changes in the electrical activity of the heart that result from abnormalities in the flow of blood.
- Blood tests measure the release of enzymes from damaged heart muscle into the bloodstream.
- A coronary angiography (using a tiny catheter inserted into an artery in a leg or arm and threaded up the artery to the heart) is performed to locate the arterial blockage prior to angioplasty or bypass surgery. A contrast material is then injected from the end of the catheter into the coronary arteries, and a high-speed series of x-rays is taken.
- It is advised to chew on an aspirin at the onset of the symptoms of a heart attack. It may help break up the clot.
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