SCREENING FOR ATRIAL FIBRILLATION

AF screening with wearable monitor beneficial in older individuals with hypertension

March 15, 2021 

Atrial fibrillation screening with wearable continuous electrocardiographic monitors was well tolerated, increased AF detection and sometimes prompted anticoagulant therapy among older individuals with hypertension, researchers reported. 

“If screening can effectively detect sufficient numbers of individuals with AF and trigger initiation of oral anticoagulation, many strokes could potentially be prevented,” David J. Gladstone, MD, PhD, scientist at Sunnybrook Research Institute in Toronto and associate professor of medicine at the University of Toronto, and colleagues wrote in JAMA Cardiology.

SCREEN-AF, a multicenter randomized clinical trial, included 856 participants aged 75 years or older (mean age, 80 years; 57% women) with hypertension without known AF from 48 primary care practices from April 2015 to March 2019. Participants were randomly assigned to the control group, which received standard care defined as routine clinical follow-up and a pulse check and heart auscultation at baseline and 6 months, or the screening group, which received a 2-week continuous ECG patch monitor at baseline and at 3 months along with standard care.

Participants in the screening group also received an automated home BP machine with AF screening capability and were instructed to use it twice daily during the periods of continuous ECG monitoring.

The primary outcome of the study was continuous ECG-detected AF or clinically detected AF within 6 months. Secondary outcomes included anticoagulant use, device adherence and AF detection by BP monitors.

Median continuous ECG wear time in the cohort was 27.4 days out of 28. The monitor detected AF among 5.3% of participants in the screening group compared with 0.5% of participants in the control group (absolute difference = 4.8 percentage points; 95% CI, 2.6-7; P < .001). Of participants with AF detected by the monitor, the median total time in AF was 6.3 hours and median duration of longest AF episode was 5.7 hours.

Researchers initiated anticoagulation therapy in 75% of participants with continuous ECG-detected AF. In total, anticoagulation therapy was prescribed for 4.1% of participants in the screening group compared with 0.9% of participants in the control group (absolute difference = 3.2 percentage points; 95% CI, 1.1-5.3; P = .003).

Twice-daily screening for AF using the home BP monitor had a sensitivity of 35%, a specificity of 81%, a positive predictive value of 8.9% and a negative predictive value of 95.9% 

Discontinuation of the continuous ECG monitor because of adverse skin reactions occurred among 1.2% of participants.

“Our trial strengthens the evidence supporting the effectiveness of screening for early detection of AF,” Gladstone and colleagues wrote. 

Perspective

Steven A. Lubitz, MD, MPH

Among adults aged at least 75 years arriving for primary care visits without known AF and with a history of hypertension, screening using a continuous 2-week patch monitor was associated with a roughly 5% rate of new AF detection at 6 months compared with 0.5% among individuals receiving usual care. Screen-detected AF was associated with a high rate of oral anticoagulation use. As expected, BP oscillometry was imperfect at detecting paroxysmal AF but was able to rule out long episodes of AF with high accuracy.

Some forms of screening include pulse palpation or ECGs. Other forms of screening are more likely to detect paroxysmal AF that self-terminates and is therefore harder to identify. These forms of screening include continuous ambulatory monitors such as the 2-week patch monitor used in the present study, or implantable monitors. The study also examined the use of a home BP monitor with the capability of detecting an abnormal pulse. Recently, consumer wearable devices such as smartwatches have also become available that have the ability to detect AF.

We need to understand whether screening is associated with a reduction in risk for stroke. We also need to know how stroke risk varies in relation to burden of AF, and whether to prescribe anticoagulation in patients with low-burden AF. Assuming that AF screening can be effective for preventing strokes, we need to also understand which methods are most effective and cost-effective.

Steven A. Lubitz, MD, MPH

Associate Professor of Medicine

Harvard Medical School

Cardiac Electrophysiologist

Massachusetts General Hospital

Disclosures: Lubitz reports he received grants from the American Heart Association, Bayer, Boehringer Ingelheim, Bristol Myers Squibb/Pfizer, Fitbit, IBM and NIH; and consulted for Bayer, Blackstone Life Sciences and Bristol Myers Squibb/Pfizer.