Home Cardiac Monitoring Technologies: A Comparison

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. Use of these devices continues to expand as healthcare shifts more and more into the home setting, and as new monitoring devices move into the marketplace. Here's a guide to the home cardiac monitors currently in use, both traditional and new.

The most frequently used types of monitors are:

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.

Similar to a Holter monitor, except that instead of recording a few days of continuous data, it is worn for up to several weeks and records data only when an event occurs. Event recordings can be triggered automatically (using an algorithm in the recording device), 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.

A term 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...