乌鸦传媒

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BARCELONA -- Twice-weekly use of a smartphone device for single-lead electrocardiogram detection of atrial fibrillation caught more cases than usual care, although with a fairly low yield in seniors with afib risk factors.

Screening picked up 3.9-fold more atrial fibrillation than found in routine care -- 19 versus five cases out of the evenly divided 1,001 participants (P=0.007), Julian Halcox, MD, of Swansea University in Wales, reported here at the European Society of Cardiology meeting and .

"The data from this study confirm results from studies with implanted pacemakers, cardioverter-defibrillators, and loop recorders and other AF screening studies that ... the more we look for AF, the more we will find it," wrote Albert Waldo, MD, PhD, of UH Case Medical Center in Cleveland, and John Camm, MD, of St. George's University of London, in an accompanying Circulation editorial.

Intermittent monitoring with a smartphone device "will tend to reveal infrequent arrhythmia, but the short recording period gives little idea of the duration of the arrhythmia, and mere identification is not enough," they cautioned, concluding: "Clearly, we have more work to do."

While the trial was underpowered for hard clinical outcomes, the number of strokes and transient ischemic attacks or systemic embolic events was nominally lower with the intervention (six versus 10, HR 0.61, 95% CI 0.22–1.69). All detected paroxysmal atrial fibrillation was treated with anticoagulation.

That "quite low" 0.02% adverse event rate in the 1,001 participants mirrored what has been seen in virtually all the previous studies looking for asymptomatic episodes of so-called subclinical atrial fibrillation, the editorialists noted. And, they pointed out, "of the 16 total strokes, 14 were either causally unrelated to AF or of undetermined origin."

In fact, there's no evidence from implantable cardiac monitors, patch monitors, or other such devices to prove that the extra detection of brief or silent afib actually translates into clinical benefit, Alfred Bove, MD, PhD, of Temple University, commented to 乌鸦传媒 in an interview. But from his early background as an engineer, "I think technology is going to solve a lot of problems," he said. "The question is what are you going to do with the data."

"These results support consideration of evaluation in an appropriately powered, event-driven randomized trial to confirm clinical and cost-effectiveness of such an approach to stroke prevention in AF," the researchers concluded.

The cost per diagnosis came in at $10,780, driven by the personnel time needed for overreads of ECGs uploaded by the device, Halcox noted at a press conference for the Hot Line session.

The projected cost per quality-adjusted life-year of $26,118 was calculated from a "hub-and-spoke" model in which ECGs are fed to commercial entities that determine which should be read by humans in a U.K. National Health Service setting. That figure was in line with other studies of systematic opportunistic screening and systematic population screening for atrial fibrillation (followed by non-vitamin K antagonist oral anticoagulation as indicated) and would likely be cost-effective compared with the current practice of no screening, the researchers noted.

Their REHEARSE-AF study (Assessment of Remote Heart Rhythm Sampling Using the AliveCor Heart Monitor to Screen for Atrial Fibrillation) included patients 65 and older with a CHA₂DS₂-VASc score of at least 2 and without a history of atrial fibrillation. Patients also had to have wireless internet access.

While the device does do automated overread of ECGs, the study included human overread of any abnormal or indeterminate results, as were 10% of normals for quality control.

Adherence with the requested Monday and Wednesday ECGs was fairly good, with about 80% of participants doing it at least once a week and more than two-thirds doing it twice a week at least 75% of weeks. Notably, the seniors reported general confidence in the device and satisfaction with it. Fewer than one in 10 using the device noted even moderate anxiety about their heart rhythm.

"These findings provide reassurance that if such a program is considered clinically and economically viable in the future, it will also be highly acceptable to the target population," the researchers wrote.