Electrocardiogram
Guide
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The EKG is read by a doctor, such as an internist, family medicine doctor, electrophysiologist, cardiologist, anesthesiologist, or surgeon. The doctor will look at the pattern of spikes and dips on your EKG to check the electrical activity in different parts of your heart. The spikes and dips are grouped into different sections that show how your heart is working.
| Normal: | The heart beats in a regular rhythm, usually between 60 and 100 beats per minute. |
|---|---|
The tracing looks normal. | |
| Abnormal: | The heart beats too slow (such as less than 60 beats per minute). The heart beats too fast (such as more than 100 beats per minute). The heart rhythm is not regular. |
The tracing does not look normal. |
What Affects the Test
You may not be able to have the test, or the results may not be helpful, if:
- The electrodes are not securely attached to your skin.
- You move or talk during the test.
- You exercise before the test.
- You are anxious or breathe very deeply or rapidly during the test.
What To Think About
- Sometimes your EKG may look normal even when you have heart disease. For this reason, the EKG should always be looked at along with your symptoms, past health, and a physical exam. If needed, other test results should be looked at too.
- An EKG cannot predict whether you will have a heart attack.
- At first, an EKG done during a heart attack may look normal or unchanged from a previous EKG. So the EKG may be repeated over several hours and days to look for changes. These are called serial EKGs.
- Sometimes abnormal EKG results can be seen only during exercise or while you have symptoms. To check for these changes in the heartbeat, an ambulatory EKG or stress EKG may be done.
- An ambulatory EKG is a type of portable, continuous EKG monitor. To learn more, see the topic Ambulatory Electrocardiogram.
- A stress EKG is a type of EKG done during exercise. A resting EKG is always done before an exercise EKG test. Results of the resting EKG are compared to the results of the exercise EKG. A resting EKG may also show a heart problem that would make an exercise EKG unsafe. To learn more, see the topic Exercise Electrocardiogram.
- EKGs are not recommended for people who are healthy and have no symptoms of heart disease.1
- Sometimes doctors automatically schedule routine tests because they think that's what patients expect. But experts say routine heart tests can be a waste of time and money. To learn more, see Heart Tests: When Do You Need Them?