What to Expect

Holter Monitor

What is a Holter monitor?

A Holter monitor is a portable electrocardiogram (ECG) that your child wears for at least 24 hours (1 full day and night) and up to 14 days.

It is about the size of a deck of cards. It comes with a shoulder strap or belt clip so your child can carry it around as they go through a normal day.

A Holter monitor is a noninvasive test.

Why is a Holter monitor used?

A Holter Monitor

Holter monitor

Holter monitors record how fast or slow the heart beats throughout the day while your child is playing, exercising and sleeping.

It helps to track symptoms such as dizziness, chest pain, fainting and palpitations (fast heart rhythms or skipping beats).

Your child’s heart doctor (cardiologist) will order a Holter monitor to check your child’s heart rate or to see if they are having an abnormal heart rhythm (arrhythmia).

How does a Holter monitor work?

A nurse or technician will attach the electrode wires (leads) of the Holter monitor to your child’s chest with stickers and place the monitor in a comfortable position. The electrodes pick up tiny electrical signals from the heart. The monitor records these signals.

When the recording is done, you will need to return or mail the monitor, leads and case to the Heart Center. We will give you a prepaid mailer.

Your child’s cardiologist will analyze the monitor’s readings and look for any times your child had an arrhythmia.

Read more about using a Holter monitor (PDF) (Spanish).

What happens during the test?

Your child will wear the monitor day and night for 1 to 14 days. You will keep a diary of your child’s activities during the day and any symptoms.

The doctor will compare your child’s diary with the Holter recording to see what kind of activity brought on any changes in heart rhythm.

How long does it take to get results of the test?

To get results, you will need to return the monitor, leads and case. After we receive them, it takes about 2 weeks for a technician to scan the information into a computer and for the cardiologist to interpret the information.

We will call you with the results, even if they are normal. If the recording shows an arrhythmia (abnormal heart rhythm), your child will need further evaluation by a cardiologist.

Contact Us 

Contact the Heart Center at 206-987-2515 for an appointment, second opinion or more information.

Providers, see how to refer a patient.

Paying for Care

Learn about paying for care at Seattle Children’s, including insurance coverage, billing and financial assistance.