What is a Holter monitor?
When symptoms, such as dizziness, fainting, low blood pressure, prolonged fatigue, or palpitations, continue to occur without a definitive diagnosis obtained with a resting electrocardiogram (ECG), your child's doctor may request an ECG tracing to be run over a long period of time. Certain arrhythmias (a fast, slow, or irregular heartbeat) which can cause the symptoms noted above may occur only sporadically, or may occur only under certain conditions, such as stress. Arrhythmias of this type are difficult to obtain on an ECG tracing that only runs for a few minutes.
A prolonged type of ECG tracing, called a Holter monitor, provides the doctor a better opportunity to capture any abnormal heartbeats or rhythms that may be causing your child's symptoms, especially if they occur frequently.
The Holter monitor test is used to record your child's ECG tracing continuously for a period of 24 hours or longer. You will receive instructions on how long your child will wear the recorder (usually 24 hours, but sometimes longer), how to keep a diary of your child's activities and symptoms during the test, and personal care and activity instructions.
What is an event monitor?
Event monitoring is very similar to Holter monitoring, and is often performed for the same reasons. With an event monitor, your child wears ECG electrode patches on his or her chest, and the electrodes are connected by wire leads to a recording device. However, unlike the Holter monitor, which records continuously throughout the testing period of 24 to 48 hours, the event monitor does not record until your child feels symptoms and you or your child trigger the monitor to record the ECG tracing at that time. An auto-trigger event monitor may be used to record rhythms when symptoms are rare or suspected to occur during sleep. The auto-trigger event monitor automatically records rhythm events and can be manually activated if your child experiences symptoms.
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. Some monitors have a feature called "memory loop recording," in which the monitor can include a recording of a short period of time prior to the moment you triggered the recording and afterwards. This feature can help your child's doctor determine more details about the possible change in your child's ECG at the time the symptoms started, and what was happening with your child's ECG just before you or your child triggered the recorder. Other monitors, called "post-event recorders," simply start recording the ECG from the moment you trigger it.
After symptoms are experienced and recorded, you will send the recording to your child's physician or to a central monitoring center. You will also keep a diary of your child's symptoms and corresponding activities, just as with the Holter monitoring procedure.
Why is Holter or event monitoring used?
Some reasons for your child's doctor to request a Holter monitor procedure include, but are not limited to, the following:
To evaluate chest pain
To evaluate other signs and symptoms which may be heart-related, such as fatigue, shortness of breath, dizziness, or fainting
To help identify irregular heartbeats
To further evaluate arrhythmias noted on a resting ECG
To evaluate for arrhythmias in children with known heart defects
How is the Holter monitor procedure performed?
The following steps provide information regarding how a Holter monitor procedure is performed:
ECG electrodes will be placed on your child's chest, and the ECG monitor will be attached to the electrodes with lead wires.
The ECG monitor is small and portable. 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 doctor's office for help.
Keeping the electrodes and monitor dry by not allowing your child to take a shower or tub 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 using electrical appliances, such as electric razors, hair dryers, or electric toothbrushes, near your child so that the ECG signal will not receive electrical interference on the recording tape. If these appliances must be used near your child, you should note it in the diary.
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.
Once your child has been hooked up to the monitor and you have been given instructions, he or she will be allowed to return to his or her usual activities, such as playing and going to school, unless the doctor 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.
At the end of the procedure, you and your child will return to the doctor's office to have the electrodes removed and the monitor discontinued. Alternatively, you may be instructed to do this yourself at a certain time and date.
Depending on the results of the Holter monitor, additional tests or procedures may be scheduled to gather further diagnostic information.