Background:
Opportunistic AF screening for primary stroke prevention is recommended in patients aged above 65 based on stroke risk models. Logistics hamper uniform screening with 12-lead ECG. Novel technologies, e.g. photoplethysmography-based (PPG) apps, may overcome this, providing readily available screening at low cost. We assessed the feasibility of smartphone screening and the impact on subsequent clinical care.
Methods:
A media campaign educated on AF, recruited subjects, and gave access to a PPG-based app to assess the heart rhythm. Subjects were instructed to measure twice daily for 8 days. An algorithm classified the traces as regular, possible AF, non-AF irregularity, or insufficient quality. PPGs of possible irregularities or AF were reviewed by medical technicians and cardiologists. If AF was confirmed, a physician visit was recommended. Questionnaires collected data on clinical care.
Results:
In 2 weeks, 62,821 subjects onboarded, resulting in 588,336 60-second PPG traces. The screened population was 49±15 years, 58% was male. In 791 subjects (1.3%), AF was diagnosed by the algorithm and offline confirmed. This group was older (62±11 years, p<0.001), more frequently male (76%, p<0.001) and had a higher CHA2DS2-VASc score (1.00±1.00 vs 2.00±2.00, p<0.001). The proportion with CHA2DS2-VASc ≥ 1 is 81.3% for the AF cohort vs 64.3% in non-AF cohort. The AF yield increased from 0.52% with 1 recording to 1.84% after 8 days. Of the AF patients, 335 (42%) were known, 373 (47%) newly identified, and 83 (11%) did not give this information. A physician was consulted by 138 (17%) newly identified patients, findings were confirmed in 71 (9%), 46 (6%) received antithrombotic therapy.
Conclusion:
This digital screening, targeting the general population and using only smartphones, demonstrates the feasibility to collect data in a scalable and low-cost way. Next to single timepoint ECG, twice-daily PPG may detect a significant number of asymptomatic AF patients.