Wearable mHealth Device Detects Abnormal Heart Rhythms Earlier
Posted on by Dr. Francis Collins
As many as 6 million Americans experience a common type of irregular heartbeat, called atrial fibrillation (AFib), that can greatly increase their risk of stroke and heart failure . There are several things that can be done to lower that risk, but the problem is that a lot of folks have no clue that their heart’s rhythm is out of whack!
So, what can we do to detect AFib and get people into treatment before it’s too late? New results from an NIH-funded study lend additional support to the idea that one answer may lie in wearable health technology: a wireless electrocardiogram (EKG) patch that can be used to monitor a person’s heart rate at home.
In people with AFib, the heart’s upper chambers (the atria) contract rapidly and unpredictably, causing inefficient and erratic blood flow. This irregularity can cause clots to form that can dislodge and travel to the brain, causing a stroke. Fortunately, medications and/or a variety of medical procedures can help to restore the heart’s normal rhythm. For those who continue to experience AFib, doctors often prescribe anticoagulant medications to reduce the risk of clots.
But for these measures to work, people first need to know they’re at risk. Right now, doctors primarily screen for AFib by checking a person’s pulse. They might also offer a stress test on a treadmill, or the opportunity to wear a “Holter” monitor, where a electrodes are attached to the chest for a day or two to record the heart’s electrical signals. The trouble is those tests can detect an irregular heartbeat only then, not over the coming months at work or home—and AFib is often intermittent.
In recent years, mobile health (mHealth) technologies have shown promise in catching more cases of AFib. They can monitor heart rhythms for several months while people go about their usual activities. That was the starting point for the NIH-supported mHealth Screening to Prevent Strokes (mSToPS) Trial. The latest results of mSToPS were published recently in the journal JAMA in a paper authored by Steven Steinhubl, Eric Topol, and their colleagues from the Scripps Translational Science Institute, La Jolla, CA .
The study tested the FDA-approved Zio patch, made by iRhythm Technologies. The Zio patch is a 2-by-5-inch adhesive patch, much like a bandage, and is worn on the upper left side of the chest. It’s water resistant and can be kept on even while a person exercises or takes a shower. The wireless patch continuously monitors heart rhythms, storing up to two weeks of EKG data for later analysis.
In the mSToPS trial, the researchers engaged fully insured members of the Aetna Commercial and Medicare Advantage health plans from around the United States. To recruit them, they relied on health records to identify those at increased risk of AFib (due to age or other cardiovascular risk factors) and sent them an email invitation to enroll.
More than 2,600 people signed up and were randomly assigned to one of two groups. The first group received a Zio patch by mail within two weeks of enrollment with instructions about how to apply and wear it at home. The second group received a Zio patch in the mail four months later with the same instructions.
After two weeks of wear, participants removed the patch and sent it to the researchers in a prepaid mailer. Over the next three months, most of the participants wore a second patch for another two weeks. The researchers downloaded the EKG data stored on the devices and analyzed them according to FDA-approved algorithms to detect AFib. If the researchers uncovered AFib or anything else unusual in the heart rhythm data, they called the participant and, if they agreed, sent those results to their doctors.
By four months, the researchers diagnosed AFib in 53 people (3.9 percent) who began active EKG monitoring right away. Only 12 people (0.9 percent) in the delayed monitoring group, who hadn’t yet received their Zio patches, were diagnosed by that same time.
The researchers also conducted a year-long observational study that followed more than 1,700 participants who underwent EKG monitoring at home in the mSToPS trial and over 3,400 unmonitored matched controls. At the end of the year, about 6 percent who used the Zio patch at home were diagnosed with AFib compared to about 2 percent of controls who didn’t use the patch.
As might be expected, those who wore the patch were also more likely to start taking anticoagulant medications and visit their primary care doctors and/or a cardiologist. But the long-term benefits of the Zio patch on reducing the incidence of strokes, ER visits, and hospitalizations are still undetermined. In fact, the researchers are now conducting a three-year followup study to get those answers.
As impressively as this replaceable patch performed in improving AFib diagnosis, one of the things that makes the mSToPS trial especially noteworthy is that the entire study was conducted remotely without the researchers or participants ever meeting face to face. This direct-to-participant clinical study shows the great potential of these types of in-home studies to evaluate the coming wave of wearable health technologies that will monitor our well-being and alert us to the first signs of trouble ahead. Over the years, we’ve highlighted many of these “wearables,” and their vast potential to diagnose illness earlier, keep tabs on air quality, or track brain activity while a person is in motion.
The recently launched the All of Us Research Program will make use of wearable technologies and their data to learn more about how individual differences in lifestyle, environment, and biological makeup can influence health and disease. The Scripps team behind the mSToPS trial is also a major partner in All of Us, helping to guide a similar digital outreach approach in our efforts to recruit 1 million or more people living all across the United States. Find out how you can join All of Us.
 Atrial Fibrillation Fact Sheet. Centers for Disease Control and Prevention.
 Effect of a Home-Based Wearable Continuous ECG Monitoring Patch on Detection of Undiagnosed Atrial Fibrillation. Steinhubl SR, Waalen J, Edwards AM, Ariniello LM, Mehta RR, Ebner GS, Carter C, Baca-Motes K, Felicione E, Sarich T, Topol EJ. JAMA. 2018 Jul 10;320(2):146-155.
Atrial Fibrillation and Stroke Information Page. National Institute of Neurological Disorders and Stroke/NIH
Steven Steinhubl (Scripps Translational Science Institute, La Jolla, CA)
NIH Support: National Center for Advancing Translational Sciences