AliveCor, makers of the Kardia Mobile smartphone-connected ECG, announced the results of several major studies of the technology, including one that was published online today in Circulation, the journal of the American Heart Association. The studies show the effectiveness of the technology in discovering atrial fibrillation that might otherwise have gone undetected, as well as its ease of use.

"Over 35 million people around the world unknowingly suffer from Atrial Fibrillation," AliveCor CEO Vic Gundotra said in a statement. "AFib is widely understood to be the leading predictor of stroke and heart failure. AliveCor's app-based digital EKG enables patients to conveniently and precisely detect AFib and to deliver clinical grade EKGs to their healthcare providers." 

The study that appears in Circulation is called the REHEARSE-AF study. In the study, about 1,000 participants aged 65 and older with no previous AFib diagnosis were split into two groups. One group recieved regular care while the other group performed twice weekly ECG scans with a Kardia Mobile device. At the end of one year, 19 AFib cases had been detected in the intervention group compared to just five in the control group. Many of the intervention group cases were asymptomatic.

User satisfaction with the device was also high -- participants overwhlemingly rated themselves comfortable using the device and not anxious about the device.

AliveCor presented a number of findings at the 2017 European Society of Cardiology Congress In Barcelona. In addition to the REHEARSE-AF study, they also presented a Cleveland Clinic study and two studies from Hong Kong.

One Hong Kong study, presented by Dr. Bryan Yan of The Chinese University of Hong Kong, looked at more than 12,000 patients aged 65 and older and found that the technology was effective at finding previously undiagnosed AFib. In the other, Dr. Ngai Yin Chan of Princess Margaret Hospital in Hong Kong presented the AFinder Study, wherein community volunteers (non-doctors) performed opportunistic screening for AFib using Kardia Mobile. Out of 10,000 participants aged 50 and older, 244 participants were found to have AFib, with 74 of those previously undiagnosed. 

Finally, the iREAD study, presented by the Cleveland Clinic's Dr. Khaldoun Tarakji, looked at the accuracy of AliveCor's automatic AFib algorithm. In 52 patients, the algorithm had a 96.6 percent sensitivity and a 94 percent specificity compared to a cardiologist's assessment of a simultaneous 12-lead EKG.