Ordinarily, when doctors wish to monitor an ambulatory patient for heartbeat irregularities, they have them wear what is know as a Holter monitor. The device is fairly cumbersome, so it's usually worn for no more than 24 hours. A recent study, however, indicates that the relatively new ZIO Patch provides more accurate readings, while being considerably less obtrusive.

A Holter monitor (seen below) typically consists of a smartphone-sized recording device that is worn by the patient, and which is wired to seven electrodes attached to their chest. Needless to say, this arrangement limits what activities the wearer can perform, plus it can be uncomfortable. Additionally, because it's only worn for a day, the number of arrhythmia events it detects may not be an accurate representation of the patient's overall pattern.

A Holter monitor setup (Photo: Jason7825)

The ZIO Patch, made by San Francisco-based iRhythm Technologies, is by contrast a self-contained electronics-packing adhesive patch. It's worn by the patient for up to two weeks as they go about their regular activities (it's water-resistant), after which they remove it themselves and mail it in to iRhythm. There, the data recorded on the patch is analyzed, with the results being sent to the patient's doctor in a report.

In the study, which was conducted by the Scripps Translational Science Institute in San Diego, 146 cardiac patients were fitted with both a Holter monitor and a ZIO Patch. The monitor was worn for the usual 24 hours, while the patch stayed on for as long as 14 days.

When the monitoring period was over, the harnesses had detected a total of 61 events, while the patches had picked up 96. This was largely due to the fact that the patches were able to be used for a longer period. Given that "bigger picture," physicians assessing the readings from the two sources were able to reach a definitive diagnosis 90 percent of the time when using the patch data, with that number dropping to 64 percent for the harness data.

The harnesses did detect 11 more events than the patches during the 24 hours when both systems were in use, although the patches subsequently noted 10 of those initially-missed events in the following days.

A paper on the research was published today in the American Journal of Medicine.

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