A heart attack or acute myocardial infarction is usually due to a complete and sudden blockage of a coronary artery. In most cases there is a pre-existing narrowing in the artery due to an atherosclerotic plaque. Immediately prior to a heart attack, a blood clot forms suddenly on the atherosclerotic plaque abruptly causing a complete blockage of the involved coronary artery. In a heart attack, heart muscle cells are being damaged and die from not having oxygen.
Chest pain is usually severe and you may experience difficulty breathing, light-headedness, and other symptoms. A heart attack is a medical emergency, potentially life threatening, and requires immediate medical attention. If you think you are having a heart attack, you must call an emergency medical service without delay.
Frequently Asked Questions
How is angina different from a heart attack (myocardial infarction)?
In angina, an area of the heart muscle is lacking in oxygen; whereas, during a heart attack, an area of heart muscle is dying from a lack of oxygen.
How are the symptoms of angina different from those of a heart attack?
In angina, the symptoms are less severe and usually subside when you stop the activity that brought on your symptoms or after taking sublingual nitroglycerin. With a heart attack, the symptoms are typically severe. The chest pain may be crushing and may come with difficulty in breathing, lightheadedness, sweating, and a sensation of impending doom. However, distinguishing angina from a heart attack can also be difficult because the symptoms of both are sometimes similar in some patients. Further, a heart attack can even be silent (without symptoms), a situation seen occasionally in people with diabetes. The diagnosis of a heart attack can be made accurately only by trained medical personnel.
Why does a heart attack happen?
A heart attack is a complex process. Usually there is a long-standing but partial blockage in the coronary artery that becomes completely blocked with the sudden formation of a blood clot. Why a blood clot suddenly forms is not entirely clear. Complete blockage of a coronary artery causes the specific area of the heart supplied by the affected artery to become oxygen-starved. The heart muscle in this area begins to die if its blood supply is not restored soon. Some heart attacks are caused by a spasm of the coronary artery; a good example of this are heart attacks associated with cocaine use.
What should I do if I think I am having a heart attack?
The most important thing to do is to call an emergency medical service for help immediately. You need to be transported to an emergency room without delay. This point cannot be emphasized more. Heart attack is a diagnosis only trained medical personnel can make, and treatment needs to be started immediately.
How is the diagnosis of a heart attack made?
The diagnosis is made by evaluating your chest pain and related symptoms, considering your medical history, taking electrocardiograms (EKG or ECG - a test which measures electrical flow through the heart to measure the functioning of the muscle), blood tests (to look for indicators of heart muscle breakdown), and sometimes imaging of the heart.
How is a heart attack treated?
If you are having a heart attack, initial treatment typically consists of medicine for the chest pain, nitroglycerin, oxygen, and intravenous drugs to dissolve the blood clot in the coronary artery. You are monitored for any heart rhythm disturbances and treated accordingly. Heart rhythm disturbances are common after a heart attack, especially during the early period. Your treatment will be continued in an intensive care unit. There, additional drug therapy is started that may include a combination of aspirin, long-acting nitroglycerin, and other cardiovascular drugs, such as beta-blockers and calcium channel blockers. Beside rhythm disturbances, you would be monitored for other complications. If everything goes smoothly, you are transferred from the intensive care unit but remain in the hospital for several additional days.
What is my risk of dying from a heart attack?
It is difficult to say because it depends on many factors. However, the death rate from a heart attack has declined by about 25% during the last 10 years because of improvements in treatment and the earlier initiation of treatment.
Can new muscle cells develop to replace the ones that have died in a heart attack?
After heart muscle cells die, they are replaced by scar tissue. However, there are usually injured heart muscle cells surrounding the immediate area where the heart attack occurred that may be salvageable. This is the rationale for starting medicine as soon as possible to dissolve the blood clot in the blocked coronary artery and quickly re-establish blood flow.
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