Definition and Overview

A Holter monitor is a portable device recommended by cardiologists and worn by patients for a certain period to track the electrical activity of the heart. This battery-operated device is used to diagnose arrhythmia (irregular heartbeat) or determine whether a previous cardiac procedure, including the implantation of a pacemaker, was successful.

A person’s heart beats around 80 times per minute but this increases depending on the activity being performed. For instance, if a person exercises, it can go up to around 100 to 120 beats per minute.

However, sometimes it becomes irregular, fast, or slow. In some cases, the irregular beats create a pattern that they become rhythmic. All these suggest arrhythmia. This usually happens when the electrical impulses that should control the heartbeat don’t function properly. The nerves could be blocked, causing the delay in the electric activity.

Although doctors consider occasional arrhythmia as harmless, chronic, recurrent, or consistent arrhythmia can be dangerous or life threatening. It may indicate heart failure, heart attack, cardiovascular disease, electrolyte imbalance, or injury in the heart, among other things.

To diagnose the electrical activity or the general condition of the heart, cardiologists often recommend an ECG (electrocardiogram). This is a type of exam wherein electrode pads are attached to the body, particularly to the chest and limbs (arms and legs). The patient is then asked to breathe (or hold the breath) while the test is ongoing. The machine that is connected to the electrode pads monitors the heart’s electrical impulses.

Usually this test is enough to make a diagnosis, but if the doctor requires more information, a Holter monitor may be used. The data obtained from the ECG will be compared to the information gathered through the Holter monitor to come up with an accurate diagnosis.

Who Needs It and Expected Results

A Holter monitor is recommended if the patient:

  • Is showing symptoms of arrhythmia – Aside from irregular heartbeat, other symptoms are dizziness, fainting spells, and unusual fatigue as well as difficulty in breathing even when not engaged in a strenuous activity.

  • Is under medication but the symptoms persist – The Holter monitor can be used to ascertain the effectiveness of the medicines prescribed by the doctor.

  • Has just undergone a cardiac surgery – The device can determine whether the pacemaker is working properly. It can also indicate if there’s an injury in the heart.

It is also essential if the ECG doesn’t provide enough information as it’s only used to monitor the heart’s activity for about an hour. The use of a Holter monitor is safe, non-invasive and effective. It is typically worn within 24 to 48 hours depending on the amount of information that the cardiologist need. The time also depends on the severity of the condition. Results typically come out after a few weeks unless they indicate a life-threatening condition.

How Does It Work?

A Holter monitor doesn’t require any special preparation except that it’s advisable to wear something loose.

For fitting, the patient is assisted by a trained technician. Like a regular ECG, the monitor also features a number of electrode pads, which are attached directly to the chest. If there’s some hair, the technician may shave the area for better adhesion. This is accomplished while the patient is standing up.

The monitor, meanwhile, may be worn in different ways. It can be placed inside a small bag or pouch, in a deep jeans or pants pocket, or on the waist. It can also be turned on and off, depending on the technician’s instructions.

Before the patient heads out, the technician provides suggestions and directions to ensure the monitor works properly and is taken care of. For instance, it should be removed when swimming or taking a bath (although it is advisable to skip a bath throughout the test). A person also cannot go through X-ray or any imaging test with the monitor. In addition, the monitor should not be placed near metallic or magnetic objects.

The technician may also provide a Holter monitor diary, or the patient can download one online to keep track of the symptoms at certain times of the day while wearing the monitor. Some of the information included in the diary are the activities performed and symptoms as well as the date and time of day they took place.

After 24 to 48 hours, the technician removes the Holter monitor and starts analyzing the recording.

Risks and Complications

In general, the Holter monitor is safe. Except for the minor inconvenience of having to bring it everywhere for up to two days. Since it is small (about the size of a modern-day camera), it is comfortable to carry around. It can also be hidden underneath the clothes.

However, one of the problems of the monitor is that it may not record all of the “events” and the times when symptoms occur. If many of these events are unrecorded, the entire test becomes moot and the doctor will still be unable to properly diagnose a patient or determine the reason of the symptoms. The patient will therefore be subjected to more tests.

Although it’s very rare, the patient may develop either an allergic reaction or a skin irritation due to the attached electrode pads. If any of these happens, the patient should immediately notify the doctor and the technician for the next steps.

Some people may also have a hard time making sure the device is turned on during events and monitoring symptoms in the diary. Incomplete data may give the doctor an inconsistent picture of the condition.

References:

  • Miller JM, Zipes DP. Diagnosis of cardiac arrhythmias. In: Bonow RO, Mann DL, Zipes DP, Libby P, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 9th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 36.
  • Olgin JE. Approach to the patient with suspected arrhythmia. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 62.
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