Holter & Event Monitor - Children's Hospital Boston

300 Longwood Avenue
Boston, MA 02115
(617) 355-6000

Clinical Services:

Holter and Event Monitor

Back to Cardiovascular Diagnostic Evaluation

What is a Holter monitor?

A Holter monitor is a small portable heart monitor, about the size of a cell phone, used to record your child's heart rhythm for a period of 24 hours. The device, which is worn in a pouch around your child's waist, is useful for identifying abnormal heartbeats or rhythms over a long period of time.

How does the test work?

The test is done over a 24-hour period as your child goes about their daily activities. The monitor has several small wires that are attached to electrode patches which are attached to your child's chest. The monitor records the activity of the heart on a magnetic tape. When the test is complete, the magnetic tape is played back through a machine and the results are reported to your doctor.

Why is the Holter monitor test used?

Some reasons your child's physician may request a Holter monitor test include:

to help identify irregular beats, called arrhythmias or dysrhythmias
to further evaluate arrhythmias noted on a resting EKG
to evaluate other signs and symptoms which may be heart-related, such as fatigue, shortness of breath, dizziness, or fainting

How is the test performed?

EKG electrodes will be placed on your child's chest, and the EKG monitor will be attached to the electrodes with lead wires. The EKG monitor is small and portable - about the size of a cell phone. The monitor may have a shoulder strap so that the monitor box may be worn over the shoulder like a shoulder bag, or it may clip to a belt or pocket.

You will be given instructions regarding:

how to keep the electrodes attached to your child's skin
how to check the monitor for problems
when to call the physician's office for help
keeping the electrodes and monitor dry by not allowing your child to take a shower or bath (a sponge bath is usually allowed) or go swimming
avoiding situations where your child may perspire excessively, causing the leads to detach
how to keep a diary during the procedure, noting the date and time of day of any changes in activity and symptoms your child experiences
avoiding the use of electrical appliances such as electric razors, hair dryers, or electric toothbrushes near your child so that the EKG signal will not receive electrical interference on the recording tape
avoiding magnets, metal detectors, areas with high-voltage electrical wires, and electric blankets during the procedure, since they can also create electrical interference on the recording tape

What happens after the monitor is attached?

Once the monitor is attached, your child will be allowed to return to his/her usual activities, such as playing and going to school, unless the physician instructs you otherwise.

You will be given a telephone number to call in case one or more of the electrodes comes off or if the monitor starts beeping.

Be sure to write down the date and time of any symptoms your child experiences in the diary, as well as what your child was doing at the time and any unusual circumstances that were also present.

When will I receive test results?

At the end of the test, you and your child may return to your physician's office to have the electrodes removed and the monitor discontinued.

Your physician will usually have the results approximately one week after you return the monitor.

What is an event monitor?

Like Holter monitoring, event monitoring is used to identify abnormal heartbeats or rhythms over a long period of time. Event monitors are often used when symptoms happen several times a week or month but not everyday.

There are two kinds of event monitors: loop event monitor and memo event monitor.

Why are event monitors used?

Some reasons your child's physician may request an event monitor test include:

to help identify irregular beats, called arrhythmias or dysrhythmias
to further evaluate arrhythmias noted on a resting EKG
to evaluate other signs and symptoms which may be heart-related, such as fatigue, shortness of breath, dizziness, or fainting

How do event monitors work?

A loop event monitor consists of a recording device and several wire leads that are connected to electrode patches that are attached your child's chest.

To record information, the monitor must be activated by you or your child when your child feels symptoms, such as chest pain, dizziness, or palpitations. Unlike the Holter monitor, which records continuously throughout the testing period of 24 to 48 hours, the loop event monitor only records information when you or your child trigger the monitor.

With the memo event monitor you or your child places a card against the skin when there are symptoms. The card then records whatever the current rhythm is. When your child feels one or more symptoms, such as chest pain, dizziness, or palpitations, one of you will push a button on the event monitor recorder.

After symptoms are experienced and recorded, the recording should be sent to your child's physician or to a central monitoring center. A diary of your child's symptoms and corresponding activities should also be kept.

When will I receive test results?

Ask your doctor. If a serious rhythm is detected by the monitor, you will usually be notified immediately by phone.