Electrocardiogram

• Sometimes your EKG may look normal even when you have heart disease. For this reason, the EKG should always be interpreted along with your symptoms, past health, physical examination, and, if necessary, other test results.
• An electrocardiogram cannot predict whether you will have a Reference heart attack Opens New Window.
• 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 (called serial EKGs) to look for changes.
• Sometimes EKG abnormalities can be seen only during exercise or while symptoms are present. 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. For more information, see the topic Reference Ambulatory Electrocardiogram.
  • A stress EKG is a type of EKG done during exercise. A resting EKG is always done before an exercise EKG test, and 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. For more information, see the topic Reference Exercise Electrocardiogram.
• Electrocardiograms are not recommended for people who are healthy and have no symptoms of heart disease.^{Reference 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. For more information, see Reference Heart Tests: When Do You Need Them?

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