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USPSTF Still Sour on Afib Screening, Even With Apple Watch

— Task force weighs in with draft recommendations for wearables and clinic alike

Last Updated May 16, 2021
Ƶ MedicalToday
Two Apple Watches, one displaying Sinus Rhythm and the other Atrial Fibrillation

Screening for atrial fibrillation (Afib) -- whether with ECG in office or via a wearable device -- cannot be recommended for middle age and older adults without symptoms.

So reaffirmed the U.S. Preventive Services Task Force (USPSTF) in a draft recommendation for asymptomatic adults 50 and older, following a similar "I" statement in 2018 for insufficient evidence that shows that benefits outweigh potential harms.

One major difference in the latest iteration was specific inclusion of wearables with ECG capabilities, like the Apple Watch, as well as smart devices using photoplethysmography, and even pulse oximeters or blood pressure cuffs with algorithms to detect irregular heartbeats that could indicate Afib.

In 2018, these devices were acknowledged without any specific recommendation related to their use.

A few trials did come along in the meantime that made the task force hopeful for moving away from an I statement, said member Chyke A. Doubeni, MD, MPH, of the Mayo Clinic in Rochester, Minnesota.

Notably, the found that one-time screening with ECG significantly increased detection of Afib when compared with no intervention, but not when compared with provider reminders for pulse palpation, which the USPSTF considered usual care. For wearables, REHEARSE-AF and mSToPS both showed that intermittent or continuous screening caught more Afib.

However, "it is important to note that intermittent or continuous screening approaches may be more likely to detect short episodes of nonpersistent [Afib]," Doubeni's group wrote.

Clinical implications for this kind of "subclinical" Afib still aren't clear. "This is a relatively new term that is applied to Afib that is just discovered by these sort of prolonged screening devices, like implantable devices, wearables, and other things. We are not quite sure what it means, because the evidence we have currently applies to people who have persistent [Afib]," the group noted.

Only one trial, REHEARSE-AF, reported on health outcomes, though it was underpowered to do so. It turned up no advantage for all-cause mortality or for a composite of stroke, transient ischemic attack, and systemic embolism with screening with an AliveCor device versus none.

The point of screening is to intervene early with anticoagulation to prevent stroke and other thromboembolic events. Stroke is the first sign of Afib for about 20% of strokes associated with Afib. But no trials have yet examined the impact of anticoagulant therapy in screen-detected populations.

The missing evidence that will be needed to move forward is a trial that compares hard outcomes -- particularly ischemic stroke -- in screened versus non-screened asymptomatic populations, Doubeni told Ƶ in an interview.

That evidence doesn't appear to be near the horizon, he said.

"We are calling for more research in this area," he added, "which is really important, because as more devices roll out, there are going to be more and more patients who are going to be coming in with, 'I got an alarm.'"

Meanwhile, "the average clinician like me -- I am a family doc -- will likely experience patients who come with a report that they recorded Afib in their device and want to discuss it," he said. "That is left to the clinical judgment of the clinician to determine."

While the had sided with the USPSTF's 2018 recommendations, the American Heart Association/American Stroke Association has given a Class IIa rating ("useful") to for Afib at primary care visits using pulse assessment (followed by ECG, as indicated).

The USPSTF draft recommendations will be through May 19.

Primary Source

U.S. Preventive Services Task Force

USPSTF "Screening for Atrial Fibrillation: U.S. Preventive Services Task Force Draft Recommendation Statement" 2021.