Coronary Heart DiseaseA heart attack happens if the flow of oxygen-rich blood to a section of heart muscle suddenly becomes blocked and the heart can't get oxygen. Most heart attacks occur as a result of coronary heart disease (CHD).
CHD is a condition in which a waxy substance called plaque builds up inside of the coronary arteries. These arteries supply oxygen-rich blood to your heart.
When plaque builds up in the arteries, the condition is called atherosclerosis. The buildup of plaque occurs over many years.
Eventually, an area of plaque can rupture (break open) inside of an artery. This causes a blood clot to form on the plaque's surface. If the clot becomes large enough, it can mostly or completely block blood flow through a coronary artery.
If the blockage isn't treated quickly, the portion of heart muscle fed by the artery begins to die. Healthy heart tissue is replaced with scar tissue. This heart damage may not be obvious, or it may cause severe or long-lasting problems.
Coronary Artery Spasm
A less common cause of heart attack is a severe spasm (tightening) of a coronary artery. The spasm cuts off blood flow through the artery. Spasms can occur in coronary arteries that aren't affected by atherosclerosis.
What causes a coronary artery to spasm isn't always clear. A spasm may be related to:
- Taking certain drugs, such as cocaine
- Emotional stress or pain
- Exposure to extreme cold
- Cigarette smoking
The major risk factors for a heart attack that you can control include:
- High blood pressure
- High blood cholesterol
- Overweight and obesity
- An unhealthy diet (for example, a diet high in saturated fat, trans fat, cholesterol, and sodium)
- Lack of routine physical activity
- High blood sugar due to insulin resistance or diabetes
In general, a person who has metabolic syndrome is twice as likely to develop heart disease and five times as likely to develop diabetes as someone who doesn't have metabolic syndrome.
For more information about the risk factors that are part of metabolic syndrome, go to the Health Topics Metabolic Syndrome article.Risk Factors You Can't Control
Risk factors that you can't control include:
- Age. The risk of heart disease increases for men after age 45 and for women after age 55 (or after menopause).
- Family history of early heart disease. Your risk increases if your father or a brother was diagnosed with heart disease before 55 years of age, or if your mother or a sister was diagnosed with heart disease before 65 years of age.
- Preeclampsia (pre-e-KLAMP-se-ah). This condition can develop during pregnancy. The two main signs of preeclampsia are a rise in blood pressure and excess protein in the urine. Preeclampsia is linked to an increased lifetime risk of heart disease, including CHD, heart attack, heart failure, and high blood pressure.