As health care shifts more and more into the home setting, corresponding shifts are occurring in the medical device landscape. New technologies are entering the market and gaining in popularity; but will they replace older technologies, supplement them or fade from use? Health technology managers need to keep abreast of the changes. Home-based cardiac monitoring is one area that has been evolving rapidly.
For patients with a suspected cardiac condition, a physician may decide that one or more types of home cardiac monitoring might be useful in diagnosis. Traditional technologies, such as Holter monitors and event recorders, have been around for decades and continue to be used. But new monitoring devices, including some consumer products, are seeing increased use.
Traditional Home Cardiac Monitors
Holter monitors, event monitors and loop recorders are common options for home cardiac monitoring. These devices vary in the method of application, the amount of data they collect and the manner in which the data is shared with health care providers.
A Holter monitor is an ambulatory ECG monitor that uses three to 12 leads. The patient wears the electrodes and an attached electronic recording device for the duration of monitoring, which typically lasts two to four days. Data is recorded continuously and is analyzed once the recorder is returned at the end of monitoring.
An event monitor is similar to a Holter monitor, except instead of recording a few days of continuous data, the monitor is worn for up to several weeks and records data only when an event occurs. Event recordings can be triggered automatically (using an algorithm), patient-initiated (typically with a button) or both. Recorded events can include a window of time before and after the trigger occurs. Typically, event monitors store fewer than 10 events. Recorded events may be sent to a physician or ECG technician for immediate analysis or transmitted daily via a telephone line, cellular connection or the Internet.
The term loop recorder is usually used to describe a type of event monitor that is implanted next to the patient’s heart. These devices record continuously on a relatively small amount of memory, overwriting data as needed. The system has two elements: the implanted monitor and a bridge device that communicates wirelessly with the monitor. When an event is detected, either automatically by an algorithm or by patient activation (using a button on the bridge device), the system captures the current data as well as data from a few minutes before and after the event. Data is downloaded from the implanted device to the bridge device, which passes the data to the clinician electronically. One common setup is to have the bridge device at the patient’s bedside so any captured loops can be automatically downloaded from the loop recorder every night and sent to the clinician. Loop recorders have to be explanted at the end of the monitoring period.
Emerging Technologies: From Home Telemetry to Smartwatches
In addition to the traditional technologies, newer options like those described below are also available. Significantly, some of these newer devices can be purchased directly by the consumer – “and that creates challenges for health care providers,” notes Brad Bonnette, a senior project officer in ECRI’s Device Evaluation group. “Organizations have little insight into the condition of the device, the patient’s ability to use it correctly, and ultimately the quality of the information that is made available to the clinician.”
Mobile cardiac outpatient telemetry, or MCOT, refers to a telemetry monitor designed to work in the home setting. It uses three to 12 leads that are connected to a transmitter the patient wears for the duration of the study (typically up to 30 days). When an event is detected, either by an algorithm or by the patient (who presses an event button on the recorder), data is transmitted wirelessly (typically over the cellular network) from the telemetry transmitter on the patient to a service center, where experienced monitor technicians analyze the data in real time and respond as necessary. Some MCOT systems can also act as a Holter monitor, recording all ECG data over the course of monitoring and storing that data locally for analysis once the unit is returned.
ECG patches are a newer alternative to Holter monitors. Like a traditional Holter, an ECG patch typically records three leads and is worn for the duration of monitoring (usually 2 to 4 days, though some devices can record up to 14 days), and data is recorded continuously and analyzed once the recorder is returned. Unlike with a traditional Holter, the electrodes and recorder are one component, which is affixed directly to the patient’s chest via an adhesive patch. The patch can be worn while the patient showers or sleeps. When monitoring is completed, the patient removes the patch and mails it to the vendor for analysis. The report is then forwarded to the ordering physician. Some ECG patches have an event button that places a marker in the recording.
Smartphone-enabled ECG monitors are FDA-cleared medical devices that can be purchased over the counter and that integrate with a smartphone application. The device is self-contained and comprises two or three electrodes. When the patient detects symptoms, they launch the application and touch the device’s electrodes with a finger from each hand to record a one-lead ECG. If the device has three electrodes, the patient can touch their left leg with the third electrode to record a six-lead ECG. The phone records an ECG for 30 seconds to two minutes, and an arrhythmia detection algorithm analyzes the waveform and alerts the patient to any abnormalities. From the application, the patient can email a PDF report, including the ECG waveform, to a clinician. Since the handheld device is purchased outright from the vendor (and typically costs $130 or less) and the application is free, the patient can use the system as long as they want.
Medical smartwatches are consumer devices that offer nonmedical applications along with one or more FDA-cleared medical applications. A medical smartwatch pairs with a smartphone for added functionality. The smartwatch is worn on the wrist and has two electrodes for recording a one-lead ECG. Typically, one electrode is on the underside of the watch, in constant contact with the wrist wearing the device. The other electrode is on the front face or side(s) of the watch. When the patient detects symptoms, they launch the smartwatch application and touch the front-facing electrode(s) with one or more fingers from the other hand. The watch records an ECG for 30 seconds, and an arrhythmia detection algorithm analyzes the waveform and alerts the patient to any abnormalities. From the paired smartphone, the patient can email a PDF report, including the ECG waveform, to a clinician. As with a smartphone-enabled ECG monitor, the smartwatch is purchased outright from the vendor, and the patient can use the system indefinitely.
To Learn More . . .
This article is adapted from ECRI’s “Home Cardiac Monitoring Technologies: A Comparison,” (Device Evaluation 2022 Aug 31). Members of ECRI’s Capital Guide, Device Evaluation, and associated programs can access the complete article, along with ECRI’s evaluations of – and product ratings for – related technologies. To learn more about membership, visit www.ecri.org/solutions/device-evaluations, or contact ECRI by telephone at (610) 825-6000, ext. 5891, or by e-mail at clientservices@ecri.org.
