What should I expect before using a Holter or event monitor?

Your doctor will do a physical exam before giving you a Holter or event monitor. He or she will:

• Check your pulse to find out how fast your heart is beating and measure your blood pressure.
• Listen to the rate and rhythm of your heart.
• Check for swelling in your legs or feet. This could be a sign of an enlarged heart or heart failure, which may cause arrhythmias (problems with the speed or rhythm of the heartbeat).
• Look for signs of other diseases (such as thyroid disease) that could be causing heart rhythm problems.

You may have an EKG (electrocardiogram) test before your doctor sends you home with a Holter or event monitor. An EKG detects and records the electrical activity of the heart for a few seconds. It shows how fast the heart is beating and its rhythm (steady or irregular). It also records the strength and timing of electrical signals as they pass through each part of the heart.

A standard EKG won't detect heart rhythm problems that don't happen during the test. For this reason, your doctor may give you a Holter or event monitor. These monitors are portable. You can wear one while doing your normal daily activities. This increases the chance of recording symptoms that only occur once in a while.

Your doctor will explain how to wear and use the Holter or event monitor. Usually, you will leave the office wearing it.

Each type of monitor is slightly different, but most have sensors (called electrodes) that are attached to the skin on your chest with sticky patches. It's important that the sensors have good contact with your skin. Poor contact can result in poor results.

Oil, too much sweat, and hair can keep the patches from sticking to your skin. You may need to shave the area on your chest where your doctor will attach each patch. You will need to clean the area with a special prep pad that the doctor will provide.

You may need to use a small amount of special paste or gel to make the patches stick to your skin better. Some patches come with paste or gel on them.

This answer from the National Heart, Lung and Blood Institute has been reviewed and/or edited by Dr. William D. Knopf.

Your doctor may do other tests, such as an electrocardiogram (EKG).

A healthcare provider will prepare the skin on your chest and attach the electrodes. The healthcare provider will clean the skin and, if necessary, clip the hair. Then the electrodes will be attached to your chest. It’s important for the electrodes to have a good connection with your skin, so a special gel or paste might be applied to your skin before the electrodes are attached.

A healthcare provider will give you the recorder. The electrodes will be attached to the recorder with wires. You’ll get a pouch so you can wear the recorder around your neck or over your shoulder. You’ll also get a diary to note your symptoms.