Every year, over one million Americans experience a heart attack, or acute myocardial infarction (AMI). Tragically, half of all AMI cases are fatal. In fact, the American Heart Association reported over 500,000 AMI fatalities in 2001. Heart disease is the leading cause of death in men and women; The AHA estimates that one in five Americans die from heart attacks each year. With these statistics, it is clear that being educated about the signs and symptoms of a heart attack is important for everyone.
A myocardial infarction leads to death of heart muscle (myocardial tissue). The affected muscle is eventually replaced by fibrous scar tissue. If an AMI causes sufficient damage, the heart cannot function. However, when symptoms of a heart attack are identified and emergency treatment is sought early, AMI damage can be minimized. Quick treatment and long-term prevention strategies greatly improve heart attack survival rates: learning to identify the symptoms of an AMI can be a life-saver.
Atherosclerosis, Thrombosis, and AMI
An AMI is usually caused by an obstruction in a coronary artery. This obstruction is often due to atherosclerosis, which causes fatty plaques to build up in the arteries. When arterial blood flow is restricted, angina, or chest pain, may result. Severe arterial narrowing may result in a heart attack.
Ninety percent of heart attacks occur when an atherosclerotic plaque ruptures. The rupture creates an open wound in the artery that leads to thrombosis (blood clot formation). A thrombosis may cause an AMI by obstructing an artery already narrowed by plaques, or the clot may break loose form the plaque, travel through the artery, and block smaller arteries. While atherosclerosis takes years to narrow arteries, a thrombosis may develop suddenly at any time during plaque development.
Atherosclerosis is the leading cause of coronary artery disease, which increases the risks of angina, thrombosis, and heart attacks.
Other Causes of AMI
A heart attack may also occur if coronary arteries spasm violently, preventing blood flow to the heart. Cigarette smoking, emotional stress, exposure to cold, certain medications, and illicit drugs, such as cocaine, can cause coronary artery spasms. Prevention of heart attacks includes avoiding these risk factors.
Angina and AMI Prevention
Angina refers to chest pain, most often caused by clogged up arteries. People with angina may experience chest pain when exercise or emotional stress strains the heart. Angina can often be controlled by simple measures, but the presence of angina symptoms indicates coronary artery disease, which increases the risk for a heart attack. People with angina are particularly encouraged to practice AMI prevention strategies.
Chest pain is one of the most common symptoms of both heart attacks and angina. Differentiating between the two conditions can be difficult. Anginal chest pain is usually alleviated with rest or after taking angina medication. Chest pain that persists, however, suggests a possible AMI. Chest pain caused by an AMI may also be accompanied by other symptoms of a heart attack, including sweating and difficulty breathing.