ECG leads are attached to a small, portable device that continuously records heart rate and rhythm over a 24-hour period or longer. Results are then analyzed with the assistance of a computer to identify heart rhythm disturbances (arrhythmias) or other cardiac problems.

Purpose of the Holter Monitoring

  • To detect and classify arrhythmias, especially in people with symptoms such as fainting, dizziness, palpitations, shortness of breath, or atypical chest pain
  • To evaluate the status of patients recuperating from a heart attack
  • To test the effectiveness of antiarrhythmic drugs or a pacemaker
  • To detect silent ischemia (deficient blood flow to the heart without symptoms such as angina) in patients with suspected heart disease but normal results on a resting ECG

Who Performs Holter Monitoring

  • A doctor, a nurse, or a technician

Special Concerns about Holter Monitoring

  • None

Before the Holter Monitoring

  • The procedure will be explained and you will have the opportunity to ask any questions.
  • Tell your doctor if you are allergic or sensitive to any tape or other adhesives.
  • Shower or bathe before starting the test as you are not be able to do so while wearing the Holter monitor.
  • In some cases, the area where the electrodes are to be placed is shaved.
  • Jewelry or other objects that can interfere with the reading must be removed.

What You Experience during Holter Monitoring

  • You will be asked to remove clothing from the waist up so that the electrodes can be attached to your chest. Only the necessary skin will be exposed and the technician will cover you with a sheet or gown.
  • ECG leads are applied to your chest or abdomen and taped securely in place. The leads are hooked up to a portable device that records your ECG on a small cassette tape or digital recorder. The device weighs about 2 lbs and is strapped or belted to your body.
  • The most common type of monitor records continuously for 24 hours. Another device can be worn for 5 to 7 days; you must activate it yourself whenever symptoms arise.
  • Go about your normal daily schedule and keep a careful diary of your activities (including walking, climbing stairs, sleeping, and sexual activity), any physical symptoms (such as dizziness), and medication doses—along with the time of day. (Most recording devices also have an “event” button that you press whenever you experience symptoms.)
  • Bathing or showering is usually prohibited, but sponge baths are permitted. Try to avoid external magnetic or electrical sources, such as metal detectors, electric blankets or toothbrushes, or high voltage areas, though they will probably not affect your results.
  • Be careful not to dislodge the leads; wearing a loose-fitting top that buttons in the front can help. If a lead loosens, the monitor light will flash and you should notify your doctor.

Risks and Complications of Holter Monitoring

  • There are no risks associated with the test; however, the monitor must not get wet.

After the Holter Monitoring

  • You should be able to resume your normal diet and activities, unless your physician instructs you.
  • Return to the doctor’s office or laboratory so the monitor and leads can be removed.

Results of Holter Monitoring

  • The ECG recording is interpreted by a computer and a report is printed. A cardiologist reviews the results along with your diary.
  • If a cardiac arrhythmia or another problem is detected, treatment will be initiated.
  • This test may fail to detect an arrhythmia if symptoms do not occur during the monitoring period. If your results are normal, it is up to your doctor to decide if further testing is needed.


The Johns Hopkins Consumer Guide to Medical Tests

Simeon Margolis, M.D., Ph.D., Medical Editor

Updated by Remedy Health Media

Publication Review By: the Editorial Staff at

Published: 12 Jan 2012

Last Modified: 13 Jan 2015