Holter monitoring

Holter monitoring or “event” monitoring is a continuous recording of your heart rhythm, usually for 24 hours but sometimes for up to one month, while you go about your usual daily activities. It is especially useful in diagnosing abnormal heart rhythms. Some common questions about Holter monitoring include:

What does it show?

An abnormal heart rhythm, called an arrhythmia, is a change in either the speed or pattern of the heartbeat. During an arrhythmia, the heart may beat too rapidly, too slowly or irregularly.

Doctors can diagnose an arrhythmia by obtaining an electrocardiogram (ECG or EKG), a recording of the heart’s electrical impulses that are recorded on a strip of moving paper.

Quite often, however, an arrhythmia will not occur during a one-minute electrocardiogram. If your doctor suspects you have an arrhythmia, he or she will want to record your heart rhythms over longer periods of time.

Holter monitoring allows your doctor to record your ECG over a period of 24 hours or longer, while you go about your usual daily activities.

Doctors may order a Holter monitor test to: Detect arrhythmia that may not occur during a standard ECG; assess recurrent symptoms, such as dizziness, palpitations or fainting spells and to evaluate the efficacy of anti-arrhythmic treatments, such as medications and pacemakers.

What is a Holter recorder?

The Holter recorder is small and portable and can be worn on a strap over the shoulder or around the waist. Your ECG is recorded continuously on a small memory card or transmitted to a central monitoring center or the cellular phone network.

Three to five small, sticky patches, called electrodes or leads, are placed on your chest and connected by wires to the recorder. Most current Holter recorders are equipped with an event marker. When you sense symptoms such as palpitations or dizziness, you press a button to note the time of your symptoms. This marks the recording so that your symptoms and ECG recording can be correlated during analysis.

How is the test done?

You’ll be fitted with the electrodes and Holter recorder by a technician at the doctor’s office or test center.

Several areas on your chest will be cleaned with alcohol and an abrasive lotion in order to ensure good electrode contact. Men may need to have areas of their chest shaved. Next, the electrodes are attached to your chest and connected by wires to the recorder. The electrodes and wires are often secured with tape. It is very important that all electrodes remain attached for the entire recording period.

The technician then checks the system to make sure is it working properly. You also may be given written instructions to take home with you. You’ll keep the recorder with you at all times for the duration of the test. You can do anything you would normally do, except take a bath or shower.

You will also carry a diary in which you will enter your activities, any symptoms you may experience during the recording period and the time when your symptoms occurred. At the end of the recording period, you’ll return to the doctor’s office or test center to have the recorder and electrodes removed. Or, you’ll be instructed on how to remove them yourself.

Why keep a diary?

You’ll keep a diary during the period you carry the recorder. The diary is very important—it enables technicians and doctors to correlate your activities and symptoms with the ECG recording.

The information you’ll need to enter in the diary includes:

• Your activities, including walking, climbing stairs, bowel movements, sexual activities, emotional upset, sleeping and taking medications.
• Symptoms you experience, such as palpitations, dizziness, fainting spells, shortness of breath or chest discomfort.
• The exact time at which these events occurred.

Your test results

Once returned, the tape is played back, scanned by a technician and analyzed by a computer. A doctor then reviews the printed report. Final results are usually available within a few days.

The information obtained from Holter monitoring helps your doctor make an accurate diagnosis and develop a treatment plan that’s best for you.