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Heart attack is a medical condition in which blood flow to a part of the heart is totally stopped or severely reduced. In heart attack, a particle of fatty deposit in a clogged coronary artery enlarges, swells, and ruptures, forming a blood clot.

The blood clot partially or totally blocks the artery, and severely restricts or completely shuts down the blood supply to the affected area of the heart. When blood flow remains stopped for a few minutes, the cells in the affected part of the heart muscle (myocardium) die. This condition is called heart attack or myocardial infarction (MI). Infarction means death of tissue. Heart attack is an emergency condition to be treated in the hospital.

GENERAL SYMPTOMS OF HEART ATTACK
A person may present certain symptoms in a heart attack, such as:

• Chest discomfort that lasts for a few minutes or that goes away and comes back.

• Intense chest pain that lasts for more than 10 to 15 minutes and is not relieved by resting or by putting 2 to 3 nitroglycerin pills under the tongue every several minutes.

• The chest pain may accompany other symptoms such as:

• Excessive sweating, especially cold sweats.

• Shortness of breath.

• Light-headedness.

• Dizziness, nausea, and vomiting.

• Pain spreading to the shoulders, neck, and arm.

• Upset stomach.

• Back pain or flu-like symptoms, especially in women.

• Pain in one or both arms, usually the left arm.

• A feeling that life is about to end.

CLINICAL SYMPTOMS OF HEART ATTACK
Physical examination of a patient in a hospital, immediately after a heart attack, will show any of the following symptoms:

• Heartbeat may be too fast or too slow.

• Blood pressure may be high or low, but generally, it is lower than normal.

• EKG often detects areas of damage to the heart, inadequate blood supply to the heart muscle, and irregular heartbeats.

• Blood test shows elevated levels of certain enzymes and proteins such as CK-MB, troponin, myoglobin, and LDH, which are usually raised in the blood when a heart attack has injured the heart muscle or some part of the muscle has died. Another blood test known as ACB (Albumin Cobalt Binding) can detect raised blood levels of free cobalt, a sign of heart attack.

EMERGENCY TREATMENT OF HEART ATTACK
As soon as you are admitted in the emergency room of a hospital with symptoms of heart attack, EKGs, X-rays, and blood tests are taken to quickly assess your condition. If your heartbeats are irregular, an electrical device called defibrillator is applied to you immediately to restore regular heartbeats. To treat you for a heart attack, the following measures may be taken in the emergency room of a hospital in which you:

• Receive oxygen.

• Chew an uncoated aspirin (160 to 325 milligrams) to prevent blood clotting and reduce the risk of death from heart attack. If chewing is not possible, an aspirin suppository (325 mg) is given. However, if you had a reaction with aspirin in the past, you will get other medications such as clopidogrel, ticlopidine, or dypyridamole, which are also helpful.

• Receive nitroglycerin pills (0.3 to 0.4 mg) under the tongue or nitroglycerin patches on the skin to dilate blood vessels for increased blood flow. (Nitroglycerin, will not be given if your blood pressure is too low).

• Receive intravenously a clot-dissolving drug called rt-PA.This drug dissolves the clot, an action that restores blood flow and saves the heart muscle from damage. To be effective, rt-PA must be given within six hours of the beginning of the heart attack symptoms and before the heart attack has caused any permanent damage to the heart muscle.

• Receive blood thinners (anticoagulants) intravenously to dissolve an existing blood clot and prevent a new clot from forming in the coronary artery. Heparin is a popularly used blood thinner. A new class of blood thinner called glycoprotein IIb/IIIa inhibitor has also been introduced. This blood thinner has been found very effective, relatively safe, and its use has resulted in reduction of death rates.

• Receive beta-blocker drugs to slow down your heart rate so that your heart work less hard and tissue damage, if any, is limited.

• Receive a drug of the ACE inhibitor class that has been shown to reduce death rates from heart attacks.

• May undergo heart surgery such as balloon angioplasty or the bypass surgery on an emergency basis. ( When the symptoms of heart attack are not relieved even after more than 12 hours of treatment from the time the symptoms started, your doctor may refer you for balloon angioplasty or the bypass surgery for restoring blood flow to your heart).

RISK FACTORS FOR HEART ATTACK
Below listed factors may increase the risk for heart attack:

• Age. Men older than 45 years, and women older than 50 (menopause age) are at high risk. However, even younger men and women can also have heart attacks.

• Family history of heart disease.

• A previous heart attack.

• Surgery such as bypass operation, stenting, or balloon angioplasty.

• Diabetes.

• High blood pressure.

• Blood cholesterol disorder.

• Lack of physical activity.

• Excess weight, especially abdominal obesity.

• Depression.

• Exposure to traffic. A study published in the New England Journal of Medicine in 2004 reported that people at risk can have a heart attack within 1 hour after their exposure to traffic in urban areas while traveling in cars, buses, and while riding on bicycles or motorcycles.

• Air pollution. A study, appearing in the medical journal Lancet in 2002, showed that a ban on burning coal in Ireland resulted in a 10 percent fall in deaths from heart disease.

PROSPECTS OF RECOVERY FROM HEART ATTACK
Studies show that when a patient gets required medical treatment within 1 hour of the beginning of symptoms of a heart attack, the prospects of survival are brighter. About 50 percent of people die of heart attack because they do not get medical treatment within 1 hour of the appearance of heart attack symptoms. By providing quick medical help, these deaths can be prevented.

Recent studies suggest that strict control of blood sugar in the period immediately after a heart attack increases the survival rate of people with diabetes. A large number of studies have shown that each 20 mg/dL increase in blood sugar over 100 mg/dL increased the risk of death in patients under intensive care in hospitals. However, patients whose blood sugar was brought down to less than 110 mg/dL through intensive insulin therapy experienced the highest survival rates.

Recovery after a heart attack, however, depends on the extent and location of the damage caused to the heart. A heart attack that damages 10 percent of the heart muscle in a critical area can cause instant death; whereas people with heart damage up to 30 to 40 percent in a less critical area of the heart muscle survive easily. Most people who survive a heart attack beyond several days usually recover fully within 2 to 3 months.