Hand-held devices including smartphones can be adapted to detect arrhythmia

CHICAGO -- Hand-held devices such as smartphones can be adapted to allow the phone to monitor a person's heart and detect atrial fibrillation with a high degree of accuracy, researchers reported here.

In a comparison of two devices, the Cardiio Rhythm and AliveCor, University of Hong Kong researchers showed that the overall accuracy of the devices in detecting atrial fibrillation among patients over the age of 65 was greater than 97%.

The sensitivity of the Cardiio Rhythm application was 92.9%, and the sensitivity of the AliveCor heart monitor was 71.4%, reported Chung-Wah Siu, MBBS, clinical associate professor of cardiology at the University of Hong Kong, in his oral presentation at the annual scientific session of the American College of Cardiology.

Siu also reported that the specificity for the Cardiio Rhythm application was 97.8% and the specificity of the AliveCor heart monitor was 99.4%. The area under the curve for the Cardiio Rhythm app was 0.95, compared with 0.85 for the AliveCor heart monitor.

"Asymptomatic atrial fibrillation is often underdiagnosed until strokes occur, precluding any meaningful prevention measures," Siu said, citing studies that indicate that as many as 40% of strokes caused by atrial fibrillation occur in patients in whom atrial fibrillation had not been diagnosed. "Modern technology makes atrial fibrillation screening more accurate, user friendly, and effective."

He said that screening patients using the standard 12-lead electrocardiogram is impracticable to perform in the clinic. But, "one possibility is that massive screening programs can be performed with the patient doing the screening by himself or herself.

"AliveCor, the Food and Drug Administration-approved atrial fibrillation screening tool, is one of the commonly used devices for atrial fibrillation in the online setting," Siu continued. "Compared with AliveCor, Cardiio Rhythm is of similar specificity but more sensitive. Given the ready availability, the Cardiio Rhythm app is more likely to be the tool for mass atrial fibrillation screening."

In the study, the screening devices detected a 2.76% incidence of atrial fibrillation among 1,013 participants – all the findings were checked with 12-lead electrocardiograms in the clinic by two cardiologists who did not know which device was used. The study also found 0.10% of patients with atrial flutter. Another 7% of patients had other heart rhythm abnormalities, Siu reported.

Patients in the study were 65 years of age or older or had diabetes and/or hypertension. They were followed for 1 year. Overall, the researchers found 1,097 individuals who fulfilled the inclusion criteria; 72 of those patients declined to be part of the trial, and 13 others failed to complete the study. Of the remaining patients, 985 were found to be free of atrial fibrillation, and 28 patients were diagnosed with atrial fibrillation.

AliveCor is a hand-held mobile electrocardiogram monitor that sends a 30-second recording to a cloud-based system that can be accessed by the doctor. Cardiio is a smartphone-based photoplethysmographic device that uses pulse waveform information collected through use of a camera app on the phone. The smartphone camera can subsequently turn that pulse waveform into a graphic demonstration that allows physicians to determine if there are abnormalities.

Still, said Anne Gillis, MD, professor of cardiac service at the University of Calgary and the Libin Cardiovascular Institute of Alberta in Calgary, who was a co-moderator of the oral abstract session, "I don't think these devices are ready yet for prime time. It requires more clinical investigation," she told MedPage Today.

"The last thing you want to do is to be generating more clinical investigations based on false positives until we have a better handle on how to use the device and interpret the results."

While the AliveCor device has been approved in Canada, Gillis said it is more widely available in the U.S.

Her co-moderator, MintuTurakhia, MD, assistant professor of medicine at Stanford University, and director of cardiac electrophysiology at the Veterans Affairs Palo Alto Health Care System in California, told MedPage Today, "In the next couple of months we are launching a number of clinical studies using wearable technologies to screen for and manage atrial fibrillation."

Source: www.medpagetoday.com