Heart Disease - Myocardial Infarction (Heart Attack)
- Overview of Myocardial Infarction (Heart Attack)
- Risk factors for Myocardial Infarction (Heart Attack)
- Warning Signs of Myocardial Infarction (Heart Attack)
Myocardial infarction (heart attack) is a serious result of coronary artery disease. Coronary artery disease occurs from atherosclerosis, when arteries become narrow or hardened due to cholesterol plaque build-up. Further narrowing may occur from thrombi (blood clots) that form on the surfaces of plaques. Myocardial infarction occurs when a coronary artery is so severely blocked that there is a significant reduction or break in the blood supply, causing damage or death to a portion of the myocardium (heart muscle). Depending on the extent of the heart muscle damage, the patient may experience significant disability or die as a result of myocardial infarction.
In addition to atherosclerosis, myocardial infarction may result from a temporary contraction or spasm of a coronary artery. When this occurs, the artery narrows and the blood flow from the artery is significantly reduced or stopped. Though the cause of coronary artery spasm is still unknown, the condition can occur in both normal blood vessels and those partially blocked by plaques.
The following risk factors have been associated with a higher incidence of myocardial infarction. Some of these risk factors are controllable (such as smoking and physical activity) while others are uncontrollable (such as age, genetics, family history).
- Age: Four out of five patients with coronary artery disease are 65 years of age or older. After menopause, females are more likely to die within the first year of having a myocardial infarction than males.
- Gender: Males are at higher risk of myocardial infarction than women, and males are also more likely to suffer myocardial infarction earlier in life. However, heart disease kills more females each year than any other disease, including breast cancer. An alarming survey reported by the American Heart Association found that only 8% of women perceive heart disease as the greatest threat to their health despite the fact that heart disease is the leading cause of death among both women and men. Over 500,000 American women die from cardiovascular disease each year--twice the number of deaths from all cancers combined. Also, women are more likely to die within the first year of a heart attack than men.
- Family history/race: A family history of heart disease increases the risk of coronary artery disease and myocardial infarction. In the United States, African Americans tend to have more severe high blood pressure than Caucasians, increasing coronary artery disease/myocardial infarction risk. The incidence of heart disease is also higher among certain population groups such as Mexican Americans, American Indians, native Hawaiians and some Asian Americans.
- Smoking: Cigarette smokers are twice as likely to experience myocardial infarction compared to non-smokers. Smokers also have a two to four time higher risk of sudden cardiac death (within an hour of a heart attack).
- High blood pressure (hypertension): Alone or in association with obesity, smoking, high blood cholesterol levels or diabetes, high blood pressure increases the risk of myocardial infarction and stroke.
- High blood cholesterol: High total and low-density lipoprotein (LDL cholesterol) levels and low HDL cholesterol levels increase the risk of myocardial infarction Cholesterol levels can be lowered with dietary/lifestyle modifications such as exercise or medications.
- Obesity: Obesity increases coronary artery disease, myocardial infarction, and stroke risk. Obesity increases strain on the heart, raises blood pressure and cholesterol, and increases diabetes risk. Weight reduction can be achieved with modifications to diet and increased physical activity.
- Diabetes: Approximately two-thirds of patients with diabetes die from heart or blood vessel disease. Adults with diabetes are three to seven times more likely to develop heart disease. A recent recommendation from the U.S. government advocates aggressive treatment of high cholesterol in people with diabetes.
- Lack of physical activity: Regular exercise reduces the risk of coronary artery disease and myocardial infarction by controlling blood cholesterol levels, decreasing the risk of obesity or diabetes, and lowering blood pressure levels in some patients.
- Stress: Research indicates a possible relationship between stress and coronary artery disease, which may lead to myocardial infarction Hypertension (high blood pressure) and high cholesterol are associated with stress, as are increased tendencies to smoke, gain weight and/or decrease physical activity.