What Are Wearable Cardiac Monitoring Devices?

Wearable cardiac monitoring devices are prescription-based medical tools that track a patient’s heart activity outside of a clinical setting. They continuously or intermittently record the heart’s electrical signals over a set period, capturing data that might not be apparent during a brief office visit. This information is used to identify the underlying cause of various heart-related symptoms.

Types of Medical-Grade Cardiac Monitors

A Holter monitor is a portable device that continuously records every heartbeat over a 24 to 48-hour period. It is prescribed to get a complete picture of the heart’s electrical activity during a patient’s normal routine. The small device is worn under clothing and attached by wires to electrodes on the chest.

For infrequent symptoms, a cardiac event monitor is used for several weeks to a month. Unlike a Holter monitor, it does not record continuously. The patient activates the device to record heart activity when they experience symptoms, though some models have an auto-trigger function that records abnormalities without patient input.

Mobile Cardiac Telemetry (MCT) is a more advanced option that provides continuous monitoring for up to 30 days. Its main feature is the ability to automatically detect and transmit abnormal heart rhythms to a remote monitoring center in near real-time. This allows certified technicians to analyze data immediately and alert the patient’s physician to urgent issues.

How These Devices Function

Wearable cardiac monitors function by detecting and recording the heart’s electrical signals using sensors called electrodes. These small, adhesive patches are applied to the chest and are sensitive to the electrical impulses generated by the heart muscle as it contracts and relaxes.

The signals are transmitted through wires to a portable recording device worn by the patient. This device processes and stores the data, creating a detailed record known as an electrocardiogram (ECG or EKG). An ECG provides a graphical representation of the heart’s rhythm and rate.

The method of data retrieval depends on the monitor type. For a Holter monitor, the ECG data is stored on a memory card, and the patient returns the device to the provider for data download. In contrast, more advanced systems transmit the recorded ECG data wirelessly for immediate review.

Common Medical Reasons for Use

Physicians prescribe wearable cardiac monitors to investigate symptoms that suggest a heart rhythm disorder. A frequent reason is to evaluate unexplained palpitations, which patients describe as a fluttering, racing, or pounding sensation. These devices help determine if the sensation is caused by an arrhythmia.

Monitoring is also used for syncope (fainting) or presyncope (severe dizziness). Since these events are brief and unpredictable, a wearable monitor can capture the heart’s activity when the symptom occurs. This helps a clinician determine if a cardiac issue, like a slow or fast heartbeat, is the cause.

These devices are also used to investigate the cause of an unexplained stroke, as a rhythm disorder like atrial fibrillation can lead to blood clots. Beyond diagnosis, monitors assess the effectiveness of treatments for known conditions or monitor a patient’s heart rhythm following a heart attack.

Data Interpretation and Clinical Significance

The data from a wearable monitor provides a log of the heart’s electrical activity as ECG tracings. This allows cardiologists and technicians to examine the heart’s rhythm for abnormalities that are too infrequent to be captured during a standard in-office ECG.

Analysis involves identifying arrhythmias like atrial fibrillation, tachycardia (a fast heart rate), or bradycardia (a slow heart rate). The final report quantifies these events, noting their frequency, duration, and timing to help a physician understand the rhythm disturbance.

A primary benefit of this monitoring is correlating the ECG data with the patient’s experience. Patients keep a diary to log symptoms, and by matching this log with the ECG, a physician can link a symptom to a specific heart rhythm. This correlation enables an accurate diagnosis and helps develop a treatment plan.

Differentiating Medical Devices from Consumer Wearables

A primary distinction between medical monitors and consumer wearables like smartwatches is their intended purpose. Prescription monitors are diagnostic tools used under a physician’s care, while consumer devices are for general wellness and fitness tracking.

The data review process also differs. Data from a medical device is analyzed by certified cardiac technicians and physicians who create a diagnostic report. Information from a consumer wearable is for the user’s personal view and lacks the professional oversight of medical monitoring.

Regulatory oversight is another dividing line. Medical monitors undergo rigorous review by bodies like the U.S. Food and Drug Administration (FDA) to validate their diagnostic accuracy. While some consumer devices have FDA clearance for certain functions, they do not replace prescription devices.

The type and quality of monitoring are also different. Medical devices use multiple electrodes to capture a detailed view of the heart’s electrical activity continuously over days or weeks. In contrast, consumer smartwatches use a single-lead sensor to perform a 30-second spot-check when activated by the user.