What is an ECG?
An electrocardiogram or ECG (sometimes called an EKG) is a noninvasive diagnostic test that records the heart's electrical activity as a graph or series of wavy lines on a moving strip of paper. It records your heart rate and rhythm and can detect decreased blood flow, enlargement of the heart, and if you are having or have previously had a heart attack. You may have a resting ECG—performed while you are lying down (at rest)—or an exercise ECG which is performed while you exercise (usually on a treadmill).
Who might have an ECG?
An ECG is one of the most common tests for diagnosing heart problems in women with risk factors or symptoms of heart disease. If you are suffering from chest pain, palpitations, fast or slow heart rhythms, shortness or breath, or lightheadedness, your doctor may recommend an ECG. It is one of the first tests given to someone suffering a heart attack.1
How do I prepare for an ECG?
You can eat and drink as usual. Talk to your doctor about any medications or dietary supplements you are taking because these may affect the accuracy of the test. You may have to stop taking or reduce the dosage of certain medications before the test.
What does an ECG entail?
You will remove your clothing (except your underwear) and put on a hospital gown. You will lie down and a nurse or technician will thoroughly clean 10 to 12 areas on your chest, arms, and legs. Small sticky patches will be attached to these clean areas of your skin. The patches are connected by wires to the electrocardiograph machine. You will then need to lie perfectly still for about a minute for a resting ECG. The entire ECG takes one to two minutes.
What do the results of an ECG indicate?
You should get the results immediately. A positive (abnormal) test does not necessarily mean that you have a heart problem and a negative (normal) test is not a sure sign that you are fine. If a problem is found, additional tests will probably be ordered. If no problems are found, you still may need to go for additional testing, such as an exercise ECG, or you may be asked to wear a Holter monitor, which is a portable tape recorder worn for 24 hours that records your heart's rhythm.
Does an ECG have any limitations?
Women are prone to inconclusive tests—the results aren't clearly positive or negative. If this happens, you may be sent for further testing, such as echocardiography or a nuclear stress test. It is possible for an ECG to miss a heart problem, especially if you are not having any symptoms during the test.