Holter Monitoring

A Holter monitor is a type of ambulatory electrocardiography, or EKG, machine that allows you to take EKG measurements on a continuing basis (usually 24 hours). Holter monitoring allows you to take EKG measurements while you are away from your doctor's office.

During Holter monitoring, two small pads with electrical contacts in the center (called leads or electrodes) are attached with adhesive to your chest. A wire runs from each lead to a lightweight battery-powered recording device that you carry either on a strap around your waist or over your shoulder. This recorder measures the electrical signal that your heart produces each time it beats. The EKG machine converts the signal into a graph that represents the activity of your heart's electrical system as waves on the graph. The EKG reading can be displayed electronically on a monitor or printed as line tracings on a piece of paper.

You may carry out all your regular activities while wearing a Holter monitor. In this way, the Holter monitor allows detection of symptoms that occur only when you perform certain activities. A standard EKG does not allow this because the range of activities you perform while at your doctor's office or in a hospital are relatively limited. While wearing the Holter monitor, you will also be asked to keep a diary of all your activities and symptoms.

Holter monitoring is done to:

  • Detect arrhythmias that occur irregularly or during certain activities.
  • Evaluate symptoms (such as chest pain, dizziness, or fainting) of possible heart disease.
  • Detect poor blood flow to your heart muscle which may indicate coronary artery disease or a heart attack.
  • Monitor the effectiveness of treatment (medication or a pacemaker or automatic defibrillator) for irregular heart rhythms.
  • Monitor cardiac function in a person who takes medications that may adversely affect the heart.

At the end of the recording period (usually 24 hours), you will either return to the doctor's office or hospital to have the electrodes removed or, if you've been taught how, you may remove the electrodes yourself. The recorded tape will be analyzed by computer to provide information about your heart rate, the frequency of beats, and any irregularities.

There is no risk associated with this test. The electrodes placed on your skin detect only electrical signals from your heart. No electricity is sent through your body and there is no possibility of receiving an electric shock.