A heart attack is when blood vessels that supply blood to the heart are blocked, preventing enough oxygen from getting to the heart. The heart muscle dies or becomes permanently damaged. Your doctor calls this a myocardial infarction.
Causes, incidence, and risk factors
Most heart attacks are caused by a blood clot that blocks one of the coronary arteries. The coronary arteries bring blood and oxygen to the heart. If the blood flow is blocked, the heart starves for oxygen and heart cells die.
In atherosclerosis, plaque builds up in the walls of your coronary arteries. This plaque is made up of cholesterol and other cells. A heart attack can occur as a result of the following:
- The slow buildup of plaque may almost block one of your coronary arteries. A heart attack may occur if not enough oxygen-containing blood can flow through this blockage. This is more likely to happen when you are exercising.
- The plaque itself develops cracks (fissures) or tears. Blood platelets stick to these tears and form a blood clot (thrombus). A heart attack can occur if this blood clot completely blocks the passage of oxygen-rich blood to the heart. This is the most common cause.
Occasionally, sudden, significant emotional or physical stress, including an illness, can trigger a heart attack.
Risk factors for heart attack and coronary artery disease include:
- Increasing age (over age 65)
- Family history of coronary artery disease (genetic or hereditary factors)
- High blood pressure
- Too much fat in your diet
- Unhealthy cholesterol levels, especially high LDL ("bad") cholesterol and low HDL ("good") cholesterol
- Chronic kidney disease
Chest pain is a major symptom of heart attack. You may feel the pain in only one part of your body, or it may move from your chest to your arms, shoulder, neck, teeth, jaw, belly area, or back.
The pain can be severe or mild. It can feel like:
- A tight band around the chest
- Bad indigestion
- Something heavy sitting on your chest
- Squeezing or heavy pressure
The pain usually lasts longer than 20 minutes. Rest and a medicine called nitroglycerin may not completely relieve the pain of a heart attack. Symptoms may also go away and come back.
Other symptoms of a heart attack include:
- Light-headedness, dizziness
- Nausea or vomiting
- Palpitations (feeling like your heart is beating too fast or irregularly)
- Shortness of breath
- Sweating, which may be extreme
Some people (the elderly, people with diabetes, and women) may have little or no chest pain. Or, they may experience unusual symptoms (shortness of breath, fatigue, weakness). A "silent heart attack" is a heart attack with no symptoms.
Signs and tests
A heart attack is a medical emergency. If you have symptoms of a heart attack, seek immediate medical help. Call 911 or your local emergency number immediately. DO NOT try to drive yourself to the hospital. DO NOT DELAY, because you are at greatest risk of sudden cardiac death in the early hours of a heart attack.
The health care provider will perform a physical exam and listen to your chest using a stethoscope. The doctor may hear abnormal sounds in your lungs (called crackles), a heart murmur, or other abnormal sounds.
You may have a rapid pulse. Your blood pressure may be normal, high, or low.
Immediately call your local emergency number (such as 911) if you have symptoms of a heart attack.
To prevent a heart attack:
- Keep your blood pressure, blood sugar, and cholesterol under control.
- Don't smoke.
- Consider drinking 1 to 2 glasses of alcohol or wine each day. Moderate amounts of alcohol may reduce your risk of cardiovascular problems. However, drinking larger amounts does more harm than good.
- Eat a low-fat diet rich in fruits and vegetables and low in animal fat.
- Eat fish twice a week. Baked or grilled fish is better than fried fish. Frying can destroy some of the health benefits.
- Exercise daily or several times a week. Walking is a good form of exercise. Talk to your doctor before starting an exercise routine.
- Lose weight if you are overweight.
If you have one or more risk factors for heart disease, talk to your doctor about possibly taking aspirin to help prevent a heart attack. Aspirin therapy (75 mg to 325 mg a day) or another drug such as prasugrel or clopidogrel may be prescribed.
New guidelines no longer recommend hormone replacement therapy, vitamins E or C, antioxidants, or folic acid to prevent heart disease.
After a heart attack, you will need regular follow-up care to reduce the risk of having a second heart attack. Often, a cardiac rehabilitation program is recommended to help you gradually return to a normal lifestyle. Always follow the exercise, diet, and medication plan prescribed by your doctor.