Consumer-Led Screening for Atrial Fibrillation: Frontier Review of the AF-SCREEN International Collaboration

Abstract

The technological evolution and widespread availability of wearables and handheld ECG devices capable of screening for atrial fibrillation (AF), and their promotion directly to consumers, has focused attention of health care professionals and patient organizations on consumer-led AF screening. In this Frontiers review, members of the AF-SCREEN International Collaboration provide a critical appraisal of this rapidly evolving field to increase awareness of the complexities and uncertainties surrounding consumer-led AF screening. Although there are numerous commercially available devices directly marketed to consumers for AF monitoring and identification of unrecognized AF, health care professional-led randomized controlled studies using multiple ECG recordings or continuous ECG monitoring to detect AF have failed to demonstrate a significant reduction in stroke. Although it remains uncertain if consumer-led AF screening reduces stroke, it could increase early diagnosis of AF and facilitate an integrated approach, including appropriate anticoagulation, rate or rhythm management, and risk factor modification to reduce complications. Companies marketing AF screening devices should report the accuracy and performance of their products in high- and low-risk populations and avoid claims about clinical outcomes unless improvement is demonstrated in randomized clinical trials. Generally, the diagnostic yield of AF screening increases with the number, duration, and temporal dispersion of screening sessions, but the prognostic importance may be less than for AF detected by single-time point screening, which is largely permanent, persistent, or high-burden paroxysmal AF. Consumer-initiated ECG recordings suggesting possible AF always require confirmation by a health care professional experienced in ECG reading, whereas suspicion of AF on the basis of photoplethysmography must be confirmed with an ECG. Consumer-led AF screening is unlikely to be cost-effective for stroke prevention in the predominantly young, early adopters of this technology. Studies in older people at higher stroke risk are required to demonstrate both effectiveness and cost-effectiveness. The direct interaction between companies and consumers creates new regulatory gaps in relation to data privacy and the registration of consumer apps and devices. Although several barriers for optimal use of consumer-led screening exist, results of large, ongoing trials, powered to detect clinical outcomes, are required before health care professionals should support widespread adoption of consumer-led AF screening.

Keywords: atrial fibrillation; screening; wearable electronic devices.

Figure 1.. Algorithms to Detect Atrial Fibrillation.

Depicted are Poincaré plots of (A) sinus rhythm and (B) atrial fibrillation, as well as (C) the algorithm used by the irregular pulse notification algorithm on the Apple Watch. One-minute pulse intervals are taken intermittently during rest and if an irregular pulse is detected, the pulse is sampled more frequently. If 5/6 pulse measurements are irregular, a possible AF alert is generated. Similar approaches have been taken by other manufacturers to increase specificity, some with greater stringency (e.g. Fitbit, which required 11 consecutive irregular overlapping 5 min tachograms, or >30 min irregular).

Figure 2.. Trade-off between duration/intensity of screening for AF detection of AF, and AF stroke risk.

While increased screening intensity increases AF detection rates, it may also identify AF associated with low stroke risk. Nonetheless, the minimum AF burden at which the risk of stroke is sufficient to justify initiation of anticoagulation remains unclear. Therefore, the trade-off between increased detection of low-burden, possibly low-risk AF by continuous monitoring strategies, could be minimized by defining an intermittent monitoring strategy that would diminish the potential for missing individuals with a high burden, which in turn is associated with higher risk of stroke. BID indicates twice daily; BP, blood pressure; ICM, intracardiac monitor; PPG, Photoplethysmogram; and QID, 4 times a day. Modified from Benjamin et al.

Figure 3.. Workflow when there is a suspicion of AF during consumer-led AF screening.

Consumer-initiated ECG recordings suggesting possible AF always require confirmation by a healthcare professional experienced in ECG reading, while suspicion of AF based on photoplethysmography must be confirmed with an ECG. If AF is confirmed, an integrated care approach, including appropriate anticoagulation, risk factor modification, and treatment of underlying cardiovascular co-morbidities, should be undertaken to reduce complications.

Figure 4.. Legal and ethical issues with consumer-led AF screening.

Important legal and ethical gaps in relation to data and registration of consumer screening apps and devices are shown.