London: A smartphone app can help accurately screen for atrial fibrillation - the most common heart rhythm disorder, a study has found.
Atrial fibrillation causes 20-30 per cent of all strokes and raises the risk of premature death, but outlook improves dramatically with oral anticoagulation therapy.
Undiagnosed atrial fibrillation is common and many patients remain untreated. Opportunistic screening is recommended in over-65s, but has time, logistical, and resource demands.
"Most people have a smartphone with a camera which is all they need to detect atrial fibrillation," said Pieter Vandervoort, of the University of Hasselt in Belgium. "This is a low cost way to screen thousands of people for a condition which is becoming more prevalent and can have serious consequences unless treated," said Vandervoort.
The study examined the feasibility and effectiveness of screening for atrial fibrillation with a smartphone app medically certified in the EU to detect the condition.
The app was made freely available by publishing an access token in a local newspaper. Within 48 hours, 12,328 adults had scanned the token and enrolled in the study.
Participants were instructed to use their own smartphone to measure their heart rhythm twice a day for one week. If they had symptoms such as heart palpitations, shortness of breath or fatigue they were advised to input them into the app.
The app is used by holding the left index finger in front of the smartphone camera for one minute, during which photoplethysmography measures the heart rhythm. Heart rhythm measurements were automatically classified as regular rhythm, possible atrial fibrillation, other irregular rhythm, or insufficient quality. Measurements indicating atrial fibrillation or other irregular rhythms were reviewed by medical technicians experienced in analysing photoplethysmography signals, under the supervision of cardiologists.
"The verification of diagnoses by medical technicians showed that interpretations by the app were very accurate, suggesting that this step could be significantly downsized and possibly omitted from a screening programme," said Vandervoort.
"According to our study approximately 225 people would need to be screened to detect one new atrial fibrillation diagnosis. This is an acceptable return, given the low cost," he said. Smartphones are becoming popular in older age groups, which are more susceptible to atrial fibrillation, researchers said. "This technology has real potential to find people with previously unknown atrial fibrillation so they can be treated," Vandervoort said.