Apple (NSDQ:AAPL) today released data from its 419,297-patient Apple Heart Study, showing that the device is capable of aiding in the detection of atrial fibrillation using its light-sensor based technology.

Results from the study were released today at the American College of Cardiology’s 68th Annual Scientific Session in New Orleans.

The study was designed to test how well Apple’s Watch could identify and prompt clinical evaluations for atrial fibrillation, the Cupertino, Calif.-based company said.

In the study, data was collected from a mobile application using Apple Watch’s photoplethysmography technology to intermittently measure blood flow activity and detect changes that could indicate an irregular contraction or heartbeat. That data, in the form of a tachogram, was then analyzed by an algorithm designed to detect irregular heart rhythms.

If the algorithm detected an irregularity, the Watch and its associated application then sent a notification to the study participant.

Researchers compared the notifications to subsequent results from a seven-day worn ECG patch, analyzing how well the algorithm on the watch matched the ECG findings, as well as the percentage of notified patients who  sought medical help through the application.

“The app continuously gathers data in the background without the wearer of the device doing anything, so it’s very opportunistic in this way. [Overall], this study improves our understanding of how this wearable technology and app works in the real-world setting and how well the technology can detect long periods of AFib,” co-principal investigator Dr. Mintu Turakhia of the Stanford School of Medicine said in a press release.

Only 0.5%, or approximately 2,100 individuals, received an irregular pulse notification. In total, 658 patients were sent a patch, of which 450 returned the patch and were included in the analysis.

Data indicates that 34% of the trial participants who were both sent a notification and had data collected via ECG patch were diagnosed as having atrial fibrillation.

“AFib can come and go, particularly early on in the course of the disease. It’s not surprising for it to go undetected in subsequent ECG patch monitoring. So while only 34 percent of people who were still having [signs of] AFib on the ambulatory ECG, that doesn’t mean that 66 percent didn’t have AFib. It just means that AFib may not have been there at the time,” Turakhia said in a prepared release.

Of the patients who received irregular pulse notifications, approximately half ended up contacting the study doctors, though others were assumed to have sought help elsewhere. Post-study surveys indicated that approximately 57% of individuals who received alerts said they sought medical attention outside the study.

Data from the trial also indicated a low rate of notifications for individuals under 40 years of age, at 0.16%, compared to just over 3% in patients over 65.

“Notifications of heart rhythm irregularities were low, an important finding given concerns about over notification, and we were able to see what happened downstream after participants received a notification,” Turakhia said in a prepared statement.

Limitations of the study included a reliance on self-reported data from participants and the failure to reach target enrollment of 500,000 participants, with a hoped for population of 75,000 individuals age 65 and over, researchers said.

Researchers said they are hopeful that the trial will serve as groundwork for future studies that look to leverage wearable technologies, and added that the next step for the study will be to explore how the monitoring tech can be used alongside other technologies, including real-time ECG, to manage heart rhythm problems.

“It really represents a paradigm shift for how clinical studies can be conducted. We don’t have to bring people into a brick and mortar clinic and give the study intervention,” Turakhia said in a prepared release.

In January, Johnson & Johnsons (NYSE:JNJ) Janssen and Apple said that they inked a deal to study if a mobile application from J&J, in combination with the Apple Watch’s ECG app and irregular rhythm notifications, can improve outcomes for people living with atrial fibrillation.

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