Researchers in Hong Kong have shown that a cardiology app can effectively screen for atrial fibrillation just by having patients place their finger over the camera.

There has been a lot of interest in using health apps to screen for atrial fibrillation. An Australian study using the AliveCor Kardia Mobile found a 1.5% incidence of new atrial fibrillation when screening patients over 65 years old came to an outpatient pharmacy. And several studies are launching using the iRhythm Zio Patch to screen nearly 3,000 patients for atrial fibrillation.

They presented the findings of their single center study testing this cardiology app at the recent American College of Cardiology annual meeting. While details are scant since the study is currently only available in abstract form, the app most likely uses a photoplethysmography (PPG) signal generated by lighting up the finger with the flash and recording using the camera.

In this study, they screened just over a thousand patients who were either (1) over 65 years old (2) had diabetes or (3) had hypertension. They also screened patients with an AliveCor Kardia smartphone EKG. In that group, there was a 2.7% incidence of atrial fibrillation. Compared to a gold standard 12-lead EKG, the CARDIIO Rhythm app had a sensitivity of 92.9%, besting the AliveCor Kardia which came in with a sensitivity of 71.4%. The specificity was 97.8% and 99.4% for the CARDIIO Rhythm app and AliveCor Kardia respectfully.

CARDIIO Rhythm isn’t the first health app designed to screen for atrial fibrillation. In the PULSESMART study, researchers from several institutions including the University of Massachusetts and University of Connecticut tested an app that screens for atrial fibrillation too. In that study, their app had a sensitivity of 97% and specificity of 94%. What’s unclear with CARIIO Rhythm is how they solved some of the challenges that the PULSESMART group was working through, in particular dealing with signal noise and ectopic beats.

Reference: Abstract, MedPage Today