Northwestern Medicine has launched an innovative clinical trial that could transform treatment protocols for millions of atrial fibrillation (AFib) patients by leveraging Apple Watch technology to reduce reliance on daily blood thinners.
The Rhythm Evaluation for AntiCoagulaTion (REACT-AF) trial, funded by the National Heart, Lung, and Blood Institute, will investigate whether a more personalized approach to stroke prevention can be as effective as current standards while reducing bleeding complications associated with continuous anticoagulation therapy.
A New Paradigm for AFib Management
AFib, characterized by fast and irregular heartbeats in the upper chambers of the heart, affects more than 5 million Americans—a number projected to reach 12.1 million by 2030. Patients with this condition face increased risks of stroke, heart failure, dementia, and premature death.
"Currently, standard of care for AFib leaves many patients on blood thinners for the rest of their lives even if they experience very infrequent arrhythmias either on their own or as the result of medications or ablation treatment," explained Dr. Rod Passman, cardiac electrophysiologist at Northwestern Medicine Bluhm Cardiovascular Institute and director of the Center for Arrhythmia Research at Northwestern University Feinberg School of Medicine.
The current approach presents significant challenges for both patients and physicians in balancing stroke prevention benefits against bleeding risks. Blood thinners, while effective at preventing clots, can cause dangerous bleeding episodes.
Wearable Technology as a Clinical Solution
The seven-year trial will recruit participants across more than 80 sites nationwide. Participants will be randomized to either receive the current standard of care—continuous blood thinners—or the innovative "pill-in-pocket" approach guided by a custom study app on Apple Watch.
"We know that risk of stroke is greatest in the weeks following an episode of AFib then returns to a low level, which suggests the potential for anticoagulant therapy only as needed rather than every day of the year," says Dr. Passman, who serves as the principal investigator for REACT-AF. "However, many patients have no symptoms of AFib, so treating in the moment is challenging. That's where wearable technology comes in."
The study will utilize Apple Watch's heart monitoring capabilities to detect AFib episodes and notify patients when they're entering an arrhythmic state. When alerted, participants in the intervention group will take blood-thinning medications only for a few weeks—the period considered highest risk for stroke—rather than continuously.
Potential Impact on Patient Care
Dr. Passman, who has spent a decade researching alternatives to the "one-size-fits-all" approach of lifelong anticoagulation, believes this strategy could revolutionize AFib management.
"If we can show this 'pill-in-pocket' strategy is equally protective against stroke and also reduces bleeding caused by these blood thinners, that could potentially save lives, reduce cost, improve quality of life and fundamentally change the standard of care for millions of patients living with AFib," he stated.
The potential benefits extend beyond reducing bleeding risks. The approach could also decrease medication costs and improve quality of life for patients who currently must take daily medication regardless of their arrhythmia frequency.
Trial Design and Participation
To participate in the clinical trial, individuals must have their own iPhone, while Apple Watch devices will be provided through a contribution from Apple. The study will compare outcomes between those receiving standard continuous therapy and those using the episodic, technology-guided approach.
Northwestern serves as the lead study site, with partnering institutions including Johns Hopkins, Stanford University, and University of California at San Francisco. The trial is registered on ClinicalTrials.gov (NCT05836987) and funded through grant number 1U24HL165066-01.
Reimagining Personalized Cardiac Care
"This is an exciting opportunity to better understand how this technology can help us better personalize patient care," said Dr. Passman. "Why should patients expose themselves to the risk and cost of these drugs when they may not be benefiting?"
The REACT-AF trial represents a significant step toward precision medicine in cardiology, potentially offering a more tailored approach to stroke prevention that aligns treatment intensity with actual risk periods rather than applying a blanket approach to all patients regardless of their individual AFib patterns.
If successful, this study could establish a new paradigm for AFib management that leverages consumer technology to deliver more personalized, effective, and safer care for millions of patients worldwide.
