A heart attack is the death of heart muscle from the sudden blockage of a coronary artery by a blood clot. Coronary arteries are blood vessels that supply the heart muscle with blood and oxygen. Blockage of a coronary artery deprives the heart muscle of blood and oxygen, causing injury to the heart muscle. Injury to the heart muscle causes chest pain and pressure. If blood flow is not restored within 20 to 40 minutes, irreversible death of the heart muscle will begin to occur. Muscle continues to die for six to eight hours at which time the heart attack usually is “complete.” The dead heart muscle is replaced by scar tissue.

Symptoms of heart attack

Although chest pain or pressure is the most common symptom of a heart attack. The pain of a heart attack is like Heartburn. The symptoms of Heart Attack are:
Feel a pressure or crushing pain in your chest, sometimes with sweating, nausea or vomiting;
Feel pain that extends from your chest into the jaw, left arm or left shoulder;
Feel tightness in your chest and/or indigestion;
Have shortness of breath for more than a couple of seconds;
Shortness of breathes;
Upper back pain;
Arm pain (more commonly the left arm, but may be either arm)

Don’t ignore the pain or discomfort. If you think you are having heart problems. The sooner you get treatment, the greater the chance that the doctors can prevent further damage to the heart muscle.
Risk factors for a heart attack
Smoking; Diabetes; Increasing age–83% of people who die from heart disease are 65 years of age or older; High cholesterol level; High blood pressure; Family history of heart attack; Lack of exercise; Stress etc.
How can heart attack be avoided? Consult to your doctor about your risk for a heart attack. Your doctor will tell you something:
Quit smoking
Eat a healthy diet
Control your blood sugar if you have diabetes.
Exercise.
Lose weight if you’re overweight.
Control your blood pressure if you have hypertension.
Talk to your doctor about whether Aspirin would help reduce your risk of a heart attack. Aspirin can help keep your blood from forming clots that can eventually block the arteries.