Heart attacks are often caused by a clot that blocks one of the coronary arteries (the blood vessels that bring blood and oxygen to heart muscle). The clot prevents blood and oxygen from reaching that area of the heart, leading to the death of heart cells in that area. Usually, this occurs in a coronary artery that has been narrowed from changes related to atherosclerosis. The damaged heart tissue permanently loses its ability to contract.

The risk factors for heart attack include:

• Smoking
• Hypertension
• Diabetes
• High fat diet
• High blood cholesterol (LDL) levels
• Obesity
• Male gender
• Age over 65
• Heredity

A personal or family history of coronary artery disease, cerebrovascular disease, peripheral vascular disease, angina (particularly unstable angina), or kidney failure requiring hemodialysis also increase the risk for heart attack.

Occasionally, sudden overwhelming stress can trigger a heart attack, but this is rare. In older persons, straining to have a bowel movement can be a risk factor.

Newer risk factors for coronary artery disease have been identified over the past several years, including elevated homocysteine levels, elevated c-reactive protein, and apo-a. Homocysteine levels can be treated with folic acid supplements in the diet. Studies are still ongoing about the practical value of these new markers.

Chest pain is a major symptom of heart attack, but in many cases the pain may be subtle or even completely absent, especially in the elderly and diabetics. Other symptoms such as weakness, shortness of breath, nausea, or vomiting may predominate.

Heart attack accounts for 1 out of every 5 deaths. It is a major cause of sudden death in adults.

Control cardiac risk factors whenever possible. Control blood pressure and total cholesterol levels, reduce or avoid smoking, modify diet if necessary (increase high density lipoproteins and decrease low density lipoproteins), control diabetes, and lose weight if obese. Follow an exercise program to improve cardiovascular fitness. (Consult your health care provider first.)

After a heart attack, follow-up care is important to reduce the risk of developing a new heart attack. Often, a cardiac rehabilitation program is recommended to help you gradually return to a "normal" lifestyle. Follow the exercise, diet, and medication regimen prescribed by your doctor.

• Chest pain below the sternum (breastbone)
• Back pain
• Abdominal pain
• Painthat radiates:
  • to the chest, arms, shoulder (See shoulder pain)
  • to the neck, teeth and jaw (See toothaches, face pain)
  • to the back
• Pain that is prolonged, typically greater than 20 minutes
• Pain similar to angina, but not relieved by rest or nitroglycerin
• Any prolonged chest pain, back pain, or abdominal pain
• Pain that may be described as:
  • "bad indigestion"
  • intense, severe, subtle, or absent
  • squeezing or heavy pressure
  • a tight band on the chest
  • "an elephant sitting on my chest"
• Sudden shortness of breath that may or may not be accompanied by pain
• Cough
• Light-headedness - dizzy
• Fainting
• Nausea
• Vomiting
• Sweating, which may be profuse (diaphoresis)
• Dry mouth
• Feeling of "impending doom"
• Anxiety

Additional symptoms that may be associated with heart attack:

• Seizures
• Fatigue
• Breathing, absent temporarily
• Breathing difficulty when lying down
• Low blood pressure
• Unusual or strange behavior

Note: The victim commonly denies that he or she may be having a heart attack. The person may have no symptoms (i.e., having a "silent attack")

Examination often reveals a rapid pulse. Blood pressure may be normal, high, or low. Listening to the chest with a stethoscope (auscultation) may show crackles in the lungs, heart murmur, or other abnormal sounds.

Heart attack and the extent of heart damage may also show on the following tests:

• An electrocardiogram (ECG), single or repeated over 2 to 3 days
• Coronary angiography
• Nuclear ventriculography (MUGA or RNV)
• Echocardiography
• Treadmill