Ambulatory Cardiac Monitoring
(Holter Monitoring; Ambulatory Electrocardiography [EKG])
by Ricker Polsdorfer, MD
Ambulatory cardiac monitoring is a way to watch and record the electrical activity of your heart. It is done as you go about your daily activities. Most of the recording devices are about the size of a cell phone.
Reasons for Test TOP
This test is used to determine whether the heart may be beating too slow or too fast. It also detects any abnormalities in heart rhythm.
Your heartbeat is regulated by electrical impulses. Sometimes there are abnormalities with these impulses. When the abnormality is happening all the time, it is easy to find in the doctor's office. But sometimes the problem comes and goes. Ambulatory cardiac monitoring records your heart’s electrical activity for long periods of time. The length of time makes it much more likely to detect an abnormality that comes and goes.
Ambulatory cardiac monitoring may be advised to assess:
Possible Complications TOP
There are no major complications associated with this test.
What to Expect TOP
Prior to Test
You will first be evaluated by a doctor. An electrocardiogram (ECG) checks the electrical activity of your heart. It will likely be done in the office.
Description of Test
The test steps will depend on the type of device used:
Certain environmental interferences should be avoided, including: magnets, metal detectors, high-voltage wires, radio frequency signalers, microwave ovens, electric blankets, electric toothbrushes, and electric razors.
After Test TOP
After the procedure, you will return the equipment.
How Long Will It Take? TOP
A typical interval is 24 hours. If your problem is less frequent than that, you may need to be monitored for a longer period of time. Longer monitoring often requires different devices.
Will It Hurt? TOP
This test will not hurt. Sometimes removing the electrodes can be uncomfortable.
The information recorded by the monitor will be evaluated. Your doctor will let you know if you need any more tests or treatment based on the study.
Call Your Doctor TOP
Call your doctor if you have trouble breathing, chest pain, or any other concerns.
If you think you have an emergency, call for emergency medical services right away.
American Heart Association
Heart Rhythm Society
Canadian Cardiovascular Society
Heart and Stroke Foundation of Canada
Abbott AV. Diagnostic Approach to Palpitations. Am Fam Physician. 2005;71(4):743-750.
Ambulatory monitors. Cleveland Clinic Heart Center website. Available at:
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Updated September 2013. Accessed August 19, 2014.
Kadish A, Buxton A, et al. ACC/AHA clinical competence statement on electrocardiography and ambulatory electrocardiography. J Am Coll Cardiol. 2001;38(7):2091-2100.
Last reviewed August 2014 by Michael J. Fucci, DO
Last Updated: 8/19/2014
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