Screening for AFib Using Wearable Activity Trackers and Telehealth

At least 2.7 million Americans have atrial fibrillation (AFib), according to the American Heart Association, but many remain unaware because they don't exhibit symptoms until they experience a stroke. Steven A. Lubitz, MD, MPH, cardiac electrophysiologist in the Telemachus & Irene Demoulas Family Foundation Center for Cardiac Arrhythmias at Massachusetts General Hospital, is leading a large-scale, all-virtual study to test whether common wearable devices trackers can help identify the condition.

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"Strokes from AFib are particularly debilitating and morbid, but they're preventable if we can detect AFib first," Dr. Lubitz says. "Thanks to a real tectonic shift over the past few years, consumer technology has emerged that is potentially capable of identifying the condition."

Dr. Lubitz has partnered with Fitbit to conduct a national study that uses the company's activity trackers and smartwatches combined with an investigational software algorithm and novel telemedicine component to identify AFib in individuals without a prior diagnosis of the arrhythmia.

Virtual Recruitument Through the App

The study is unique in many ways, Dr. Lubitz says, including how it recruits and enrolls subjects—entirely virtually:

1. Eligible users who already owned and wore one of the company's eligible trackers and smartwatches containing photoplethysmography technology were notified of the study and invited to participate at no cost
2. Volunteers provided informed consent online and fill out a baseline questionnaire electronically
3. After a participant enrolled, pulse wave data from the individual's tracker or smartwatch was processed by the investigational software algorithm
4. When the algorithm identified abnormal heart activity that may be suggestive of AFib, the participant was notified

"We can easily and rapidly recruit large numbers of participants simply by inviting existing consumers to participate. It would take a very long time to accrue and enroll such numbers using conventional recruitment approaches," Dr. Lubitz says. "We're able to rapidly power our study to determine quickly whether the alerts that the algorithm generates are accurate or not."

Telehealth as the Future of Medicine

Patients flagged by the software have the option to participate in the next unique phase of the study:

1. They received an invitation for further screening via a telemedicine platform. A health care practitioner offered to prescribe and mail a medical-grade patch monitor
2. The patient wore the patch monitor for one week, then mailed it back
3. During a follow-up telemedicine encounter, the telehealth platform disclosed the patch monitor results and advised the patient accordingly. If the patch monitor confirmed the findings of the investigational software, the patient was advised to seek follow-up care

"There may be a potential role within the health care system for third-party vendors that can take care of some routine testing that doesn't require patients to interact with their regular providers," Dr. Lubitz says. "This innovative and novel telehealth component reflects where medicine is going."

Mass General's research team is currently monitoring enrollment to make sure they are accruing subjects at a rate that powers the study adequately. Their goal is to reach a total of at least 500 who progress to wear the medical-grade patch monitor.

Dr. Lubitz estimates that they will have the investigational algorithm, patch and questionnaire data they need to proceed with statistical analysis in the coming year. And then the team of investigators including Andrea Foulkes, ScD, director of Biostatistics, Daniel Singer, MD, internist, and Steven Atlas, MD, of Primary Care, in further collaboration with Fitbit, will determine the positive predictive value of the algorithm.

Extending AFib Research

The results of that study will complement a suite of recent AFib studies at Mass General. Dr. Lubitz and others at the institution have long had an interest in understanding who is at risk for developing AFib and how to prevent strokes in AFib patients.

For example, Dr. Lubitz leads a related study, VITAL-AF, which is using single-lead electrocardiography to screen for AFib during primary care visits. He also co-leads GUARD-AF, a study examining whether early screening for AFib can prevent stroke.

Monitoring as a Wearable, Workable Reality

"This is an exciting time for medicine," Dr. Lubitz says. "We are on the verge of implementing new ways of delivering health care that improve outcomes for patients in ways that seemed like only science fiction a few years ago. With respect to AFib detection, people can wear devices for days, weeks, months, even years."

However, he says, there is a lot of work to do to make sure that the immense and growing amount of data from consumer wearable devices are reliable and well-integrated into clinical workflows.

"My peers, especially in the cardiovascular community, routinely see patients in their offices who show them their heart rates, sleep measurements, electrocardiography or some other data from consumer devices. They are probably being bombarded by this kind of information," he says. "This study is helping to add some rigor and certitude regarding the validity of identifying AFib with abnormal heart rates detected using consumer technology."

Learn more about the Telemachus & Irene Demoulas Family Foundation Center for Cardiac Arrhythmias

Refer a patient to the Corrigan Minehan Heart Center