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 ECG, a child’s doctor may request an ECG tracing to be run during a long period of time. Certain arrhythmias (a fast, slow or irregular heart beat) 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 heart beats or rhythms that may be causing the child’s symptoms, especially if they occur frequently.
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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, a child wears ECG electrode patches on his 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 the child feels symptoms and a parent of the 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.
If the child feels one or more symptoms, such as chest pain, dizziness or palpitations, either the parent or the child 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 the event monitor is triggered for recording and afterward. This feature can help the child’’s doctor determine more details about the possible change in the child’’s ECG at the time the symptoms started, and what was happening with the child’’s ECG just before the recorder is triggered by the parent or child. Other monitors, called postevent recorders, simply start recording the ECG from the moment it is triggered.
After symptoms are experienced and recorded, the recording will be sent to the child’s doctor or to a central monitoring center. Parents will also keep a diary of their child’’s symptoms and corresponding activities, just as with the Holter monitoring procedure. When reporting an event on the phone, parents need to tell the person receiving the call what the child was doing when the recording was made, not what he was doing during the transmission.
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Why is Holter or event monitoring used?
Some reasons for the 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 beats
- To further evaluate arrhythmias noted on a resting ECG
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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 the child’s chest, and the ECG monitor will be attached to the electrodes with lead wires.
- The ECG monitor is small and portable—about the size of a deck of cards. 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 the 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 the child to take a shower or tub bath (a sponge bath is usually allowed) or go swimming
- Avoiding situations where the 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 the child experiences
- Avoiding using electrical appliances such as electric razors, hair dryers or electric toothbrushes near the child so the ECG signal will not receive electrical interference on the recording tape. If these appliances must be used near thechild, parents should note it in the diary.
- Avoiding magnets, metal detectors, areas with high-voltage electrical wires and electric blankets during the procedure, because they can also create electrical interference on the recording tape
Once the child has been hooked up to the monitor and the parents have been given instructions, he will be allowed to return to his usual activities, such as playing and going to school, unless the doctor instructs the child otherwise.
- Parents will be given a telephone number to call in case one or more of the electrodes comes off or if the monitor starts beeping.
- Parents will need to write down the date and time of any symptoms their child experiences in the diary, as well as what their child was doing at the time and any unusual circumstances that were also present.
- At the end of the procedure, the parents and child will return to the doctor’s office to have the electrodes removed and the monitor discontinued. Alternatively, parents may be instructed to do this themselves at a certain time and date, and return the monitor by mail.
Depending on the results of the Holter monitor, additional tests or procedures may be scheduled to gather further diagnostic information.
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