What do you get when you combine a smartphone app with a hand-held wireless single lead heart monitor (ECG)? A cheap and accessible method of testing for irregular heart rate — a potentially fatal condition known as atrial fibrillation (AF), according to research published online in the journal Heart.
The researchers believe the method might be particularly useful for systematic mass screening, given that no symptoms of AF had manifested in two-thirds of cases detected.
AF is associated with a heightened risk of stroke, heart failure and death, and its prevalence is predicted to triple in the United States by 2050, because it is increasingly more common after the age of 65. But appropriate treatment can cut the risk of a stroke by up to 70%.
The researchers tested more than 13,000 adults in Hong Kong for AF between May 2014 and April 2015, using a smartphone app combined with a hand-held, wireless, single lead heart monitor. Participants were recruited to this community screening program as a result of media campaigns and posters in community hubs.
The test, which lasted 30 seconds, picked up 101 cases (0.8%) of AF that had not been diagnosed before. In two thirds of these cases, the condition was symptomless, but their combined risk scores topped 3, suggesting that they would have benefited from treatment.
The result was not interpretable in only 56 (0.4%) of those tested.
Overall, almost one in 10 (8.5%) of those tested had AF — a prevalence that is comparable with that of populations in developed countries. Increasing age (60 and older), male gender, weight and a history of heart disease or surgery and peripheral vascular disease were all predictive of the condition.
Current guidelines recommend opportunistic screening for AF, but the researchers suggest that their findings indicate that systematic mass screening might instead be feasible.
"A systematic population-based ECG screening for AF, instead of an opportunistic approach, as recommended by the current [European Society of Cardiology] guidelines, may lead to a reduction in the incidence of stroke in the community," the researchers conclude, advocating the need for a well-designed clinical trial to test this out.
The findings are important, say Swedish cardiologists, Drs. Emma Svennberg and Johan Engdahl, from the Karolinska Institute and the Sahlgrenska Academy at Gothenburg University, respectively, in a linked editorial — but they sound a note of caution.
Systematic mass screening programs for AF have not achieved coverage of more than 50% when targeted at those most at risk — uptake that is lower than most other established screening programs, they say. And while the results are promising, "much more data on the optimal mode and duration of ECG recording are needed."
They go on to say that a major drawback of the research is the lack of data on the proportion of people who received appropriate medication (anticoagulants) after their test, pointing out that screening alone does not afford protection against the risk of stroke.
"In order to relieve both patients and society from the consequences of untreated AF, we believe and hope that AF screening in risk groups will be a part of the standard health care in many countries in the near future," they write.