AF Screening Leads the Charge in Cardiology's Digital Revolution

In a world where medical practice is increasingly reliant on healthcare technology, cardiology practice is on the leading edge of the revolution. In fact, atrial fibrillation (AF) is proving to be one of the diseases most amenable to contemporary applications. Why? Prevalence and incidence of the disease continue to increase while monitoring technologies simultaneously become more sophisticated, making AF the prototypical disease to prove that medical technology can indeed change the way in which a disease is diagnosed and managed.

The REHEARSE-AF study,¹ presented at the European Society of Cardiology Congress in Barcelona in August 2017 and published in Circulation, demonstrated the efficacy of the AliveCor handheld device for AF screening in patients >65 years of age, who had a CHA₂DS₂-Vasc ≥ 2 and had access to internet via Wi-Fi. Patients (N=1001) were randomized either to AliveCor screening (iECG) or to routine medical care. iECG screening was comprised of recording and submitting an ECG trace twice a week.

[[{"type":"media","view_mode":"media_crop","fid":"63117","attributes":{"alt":"","class":"media-image media-image-right","id":"media_crop_7964521179497","media_crop_h":"0","media_crop_image_style":"-1","media_crop_instance":"8045","media_crop_rotate":"0","media_crop_scale_h":"0","media_crop_scale_w":"0","media_crop_w":"0","media_crop_x":"0","media_crop_y":"0","style":"float: right; height: 243px; width: 348px;","title":"Image courtesy of AliveCor","typeof":"foaf:Image"}}]]Of 501 patients in the iECG group, 3.8% (n=19) were diagnosed with AF over the 12-month period compared with 1% (n=5) in the routine care arm (HR 3.9, 1.4-10.4, p=0.007). Of the 19 patients diagnosed with AF, 42% were asymptomatic and 37% had non-palpitation symptoms, which may have otherwise not led to the diagnosis of AF. Overall, this resulted in a cost per AF diagnosis of $10,700 with the device, with the majority of the cost coming from the physician’s time for over-reading the device tracing. Interestingly, but not a surprise, a high CHA₂DS₂-Vasc score emerged as a significant independent predictor of AF. Of all the ~60,000 ECGs, 76% were normal, ~21% could not be detected by the computer algorithm (6% of these were later read as AF) and 2.2% were considered uninterpretable (whether by computer or physician over-read). Shockingly, of the 1% of ECGs interpreted as “AF” by the algorithm, only 5% of these were actually confirmed by physician over-read to be AF.

From implantable devices that serve as continuous cardiac monitors, to small implantable loop recorders (such as the LINQ) placed after cryptogenic stroke² and now to the handheld AliveCor device, the technology designed for AF diagnosis continues to evolve rapidly. This study highlights the benefits advanced technology has afforded us in diagnosing AF but also tells us that we have a way to go to improve our automation. Plus, the price we pay for technology isn’t cheap!  The cost per AF diagnosis, as it stands with the current technology, is quite high and better, underscoring the need for more accurate algorithms to help decrease the cost of this screening tool before such technology can be widely adopted. Stay tuned…

References:

1. Halcox JPJ, Wareham K, Cardew A, et al. Assessment of remote heart rhythm sampling using the AliveCor heart monitor to screen for atrial fibrillation: The REHEARSE-AF study. Circulation 2017; DOI:10.1161/CIRCULATIONAHA.117.030583

2. Sanna T, Diener H-C, Passman RS, et al. Cryptogenic stroke and underlying atrial fibrillation. N Engl J Med 2014; 370:2478-2486.