Ambulatory Cardiac Monitoring
(Holter Monitoring; Ambulatory Electrocardiography [EKG])
by Cynthia M. Johnson, MA
Ambulatory cardiac monitoring watches and records heart activity during the day. Most devices are about the size of a mobile phone.
Reasons for Test
This test is done to find out whether the heart is beating too slow or too quickly. It also looks for heart rhythm problems.
The test records your heart’s electrical activity for long periods of time. This makes it more likely to find a problem that comes and goes. It may be used to learn more about:
This test does not cause problems.
What to Expect
Prior to Test
An ECG will be done to check the electrical activity of your heart.
Description of Test
The test steps depend on how it will be done:
You will need to stay away from things like magnets, metal detectors, high-voltage wires, microwave ovens, and electric devices. They may cause problems with the test.
You will return the device after the test.
How Long Will It Take?
The test is often done for 24 hours. Some people may need to be monitored longer.
Will It Hurt?
This test will not hurt.
Your doctor will look at the data and let you know whether you need more tests or treatment.
Call Your Doctor
Call your doctor if you have trouble breathing, chest pain, or any other problems.
If you think you have an emergency, call for medical help right away.
American Heart Association
Heart Rhythm Society
Canadian Cardiovascular Society
Heart and Stroke Foundation of Canada
Ambulatory cardiac telemetry monitoring. EBSCO DynaMed website. Available at: https://www.dyname.... Updated June 7, 2017. Accessed November 19, 2019.
Ambulatory monitors. Cleveland Clinic Heart Center website. Available at:
...(Click grey area to select URL)
Updated April 22, 2019. Accessed November 19, 2019.
Priori SG, Blomström-Lundqvist C, et al. 2015 European Society of Cardiology (ESC) Guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death. Endorsed by: Association for European Paediatric and Congenital Cardiology (AEPC). Eur Heart J. 2015 Nov 1;36(41):2793-2867.
Last reviewed September 2019 by EBSCO Medical Review Board James P. Cornell, MD
Last Updated: 9/25/2020