Cardiac Holter

General Description

Ambulatory electrocardiographic monitoring, commonly known as a cardiac Holter due to the name of the device used for this test, is a diagnostic procedure that continuously records the heart’s rhythm in an outpatient setting, usually at home. To do this, patients carry the electronic recording device in a pocket or in a pouch secured around the waist with a strap. The device has between 5 and 7 leads (wires) with electrodes at the ends, which are placed on the chest to digitally capture the heart’s signals. The monitor is battery-operated.

A Holter monitor is typically used when previous tests (electrocardiogram or electrocardiography) have yielded inconclusive results. Depending on the specific aspects to be analyzed, different types of Holter monitors are used:

• Electrocardiographic Holter: The patient wears this portable device for 24 to 48 hours while performing their usual daily activities.
• 7-day Holter: Used for individuals with paroxysmal arrhythmias, meaning those that occur intermittently. This device has a battery life of up to one week and records heart activity until symptoms appear.
• Event Holter: Operates with long-lasting batteries that can last up to 40 days. This allows patients with sporadic symptoms that are not detected by routine electrocardiograms to activate the recording when they begin to experience symptoms.
• Subcutaneous Holter: This implantable device is placed under the skin of the chest, near the heart. It records events when the patient activates it using a remote control and stores the data in its memory. It has a lifespan of approximately two to three years and is typically used for individuals who experience symptoms only every few months.

When is it indicated?

A Holter monitor is commonly used to diagnose or further study various types of cardiac arrhythmias and coronary diseases. This test is generally performed on patients who experience palpitations, tachycardia, or dizziness.

• Electrocardiographic Holter: Indicated for patients with frequent heart rhythm disturbances. It is used to study cases of syncope, palpitations, or ischemic heart disease. Additionally, it is a useful tool for assessing whether a pacemaker is functioning properly or if a patient’s medication regimen needs adjustment.
• 7-day Holter: Used to evaluate paroxysmal arrhythmias that cause symptoms intermittently.
• Event Holter: Also used for studying paroxysmal arrhythmias, but in cases where symptoms occur less frequently.
• Subcutaneous Holter: Suitable when there is suspicion of arrhythmias, atrial fibrillation, tachycardia, or recurrent syncope, but routine tests have not provided clear information.

How is it performed?

To conduct an external Holter test, the following steps are taken:

• Electrodes are placed on the patient’s clean, dry chest skin using adhesive material.
• The wires are connected to the device, which is stored in a pouch that remains attached to the body.
• The patient resumes their normal routine so that heart activity can be recorded. Bathing and showering should be avoided, as the device cannot get wet.
• Once the designated monitoring period is over, the specialist removes the electrodes and extracts the recorded data for evaluation and diagnosis.

The implantable subcutaneous device requires a minor outpatient surgical procedure lasting approximately 15 to 20 minutes. To implant the device, local anesthesia is administered, and a small incision of about two centimeters in length and approximately eight millimeters in depth is made to insert the Holter. The incision is then closed, and proper wound care is necessary to ensure smooth healing without complications. After the procedure, the patient can return to their routine almost immediately.

Risks

Using a Holter monitor poses no health risks. In rare cases, mild skin irritation may occur where the electrodes are placed.

Although uncommon, implantable Holter devices may present some complications, such as infection after surgery or device displacement, making it visible under the skin.

What to expect from a Holter test

Whether external or subcutaneous, the Holter device is placed in an outpatient setting, requiring neither hospitalization nor post-procedure rest. Patients are advised to wear loose, comfortable clothing that can be easily removed, ensuring that the wires are not compressed. If necessary, chest hair may be shaved to ensure that the electrodes adhere properly. Once in place, patients should continue their normal activities without avoiding any efforts (except for excessive physical exercise) since specialists need to assess the heart’s response to typical daily activity. Although it may feel noticeable at first, the device and its wires usually become unnoticeable after a short period.

Before undergoing the surgical procedure to implant a Holter device, patients must sign an informed consent form. An intravenous line may be placed to administer medication. During the procedure, the patient remains awake, as local anesthesia is applied to the left side of the chest, just below the collarbone. The surgery lasts about 20 minutes, and after approximately one hour of observation, the patient can return home. Around ten days later, stitches or staples are removed at a follow-up visit with a nurse or primary care doctor.

In some cases, the doctor may ask the patient to keep a record of their daily activities, particularly noting the intensity of movements, to provide additional information if any heart rhythm abnormalities are detected.

To minimize the risk of alterations in the results, patients should be cautious to avoid impacts to the device and pulling on the wires. Extra care should be taken around magnets, electrical devices, and mobile phones, and patients should avoid passing through magnetic arches or staying in areas with high-voltage electrical fields.

Test results are provided in a follow-up consultation several days after the data has been collected.

Medical specialties that request a cardiac Holter

Cardiology specialists and professionals in cardiovascular risk units are the doctors who most frequently use this diagnostic method.