New method of interpreting cardiac telemetry accurately spots AF in stroke patients

By WIll Boggs MD

NEW YORK (Reuters Health) - 4/7/2019

Electrocardiomatrix, a new method of evaluating electrocardiography (ECG) signals, accurately identifies atrial fibrillation (AF) in patients admitted for ischemic stroke or transient ischemic attack (TIA), according to an observational study in a stroke unit.

"Electrocardiomatrix (ECM) is by far the most accurate method for AF detection and can dramatically reduce both false-positive and false-negative detection of AF," Dr. Jimo Borjigin of the University of Michigan Medical School, in Ann Arbor, told Reuters Health by email. "Application of ECM technology is predicted to promote accurate detection of all cardiac arrhythmias that traditionally rely on ECG inspection."

ECM displays ECG data in a three-dimensional matrix format that allows for easier detection of such abnormalities as AF.

Dr. Borjigin's team applied the technique to real-time stroke-unit telemetry data from 265 patients with ischemic stroke or TIA to determine its feasibility for identifying AF.

The overall positive predictive value (PPV) of ECM for AF detection was 86%, and among 212 patients without a history of AF, its PPV was 100%, the researchers report in Stroke, online June 10.

Among 48 patients with a history of AF, 24 were AF-positive by both the clinical team's interpretation of telemetry and ECM, 16 were AF-negative by both telemetry and ECM, and five of the remaining eight were deemed positive by ECM analysis alone, while three were deemed AF-positive by telemetry alone.

Of the 212 patients without a history of AF, eight were found to be positive by both methods, while two were identified to be AF-positive only by telemetry.

All AF events flagged by ECM that were not identified by telemetry were confirmed by a study cardiologist's review of the standard telemetry as actual AF. And all five cases documented by telemetry but not identified by ECM were confirmed as false positives (frequent premature atrial or ventricular contractions).

"I was most surprised by the finding that our technique is more accurate in AF detection than the current gold standard (manual annotation by trained physicians)," Dr. Borjigin said. "I envision that ECM can be installed in all ECG machines that will display, simultaneously, both ECG (in short, 5-10 sec, segments) and ECM (50-60 min segments) data, which will allow real-time, rapid, and precise detection of AF (and other arrhythmias) in patients."

"The software can also be used to analyze ECG signals post-collection using a software package," she said. "Recognition of arrhythmias on ECM is very intuitive. We can provide tutorials for the use of ECM to facilitate easy adoption of the technique."

Dr. Borjigin is the coinventor of electrocardiomatrix, for which she holds a patent in Japan and for which the Regents of the University of Michigan hold the patent in the United States.

SOURCE: https://bit.ly/2YkIOYQ

Stroke 2019.

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