Smartwatch-guided blood thinner use for atrial fibrillation
2/2 REACT-AF: Rhythm Evaluation for AntiCoagulaTion with Continuous Monitoring of Atrial Fibrillation
This compares taking blood thinners continuously versus only after an Apple Watch detects at least one hour of atrial fibrillation for people with paroxysmal or persistent AF and low-to-moderate stroke risk.
Quick facts
| Grant type | NIH-funded research |
|---|---|
| Study type | NIH-funded research |
| Funding institution | Johns Hopkins University NIH-funded |
| Lab location | 1 site (Baltimore, United States) |
| Project ID | NIH-11158776 on NIH RePORTER |
What this research studies
If you join, you'll be randomly assigned to either take a direct oral anticoagulant (DOAC) all the time or to take short, time-limited DOAC courses only when your Apple Watch detects at least one hour of AF. The watch will continuously monitor your heart rhythm and trigger treatment when AF episodes meet the study threshold. Doctors will track strokes, bleeding events, and other outcomes over the follow-up period. The trial enrolls people with paroxysmal or persistent AF and a CHA2DS2-VASc score of 1-4 at multiple U.S. centers led by Johns Hopkins.
Who could benefit from this research
Good fit: People with paroxysmal or persistent atrial fibrillation, a CHA2DS2-VASc score of 1-4, able and willing to wear an Apple Watch and take DOACs as directed.
Not a fit: People with high stroke risk, permanent continuous AF, inability to use a smartwatch, or contraindications to DOACs are unlikely to benefit from this trial approach.
Why it matters
Potential benefit: If successful, this approach could lower bleeding risk while still protecting against stroke by matching blood thinner use to actual AF episodes.
How similar studies have performed: Smartwatch detection of AF has been validated in prior work, but using smartwatch-triggered, time-limited anticoagulation is a novel strategy not yet proven in large randomized trials.
Where this research is happening
Baltimore, United States
- Johns Hopkins University — Baltimore, United States (Active)
Researchers
- Principal investigator: Hanley, Daniel F — Johns Hopkins University
- Study coordinator: Hanley, Daniel F
About this research
- This is an active NIH-funded research project — typically early-stage science, not a clinical trial accepting patient enrollment.
- Some NIH-funded labs run parallel clinical studies or seek volunteers for related work. To check, contact the principal investigator or institution listed above.
- For full project details, budget, and progress reports, visit the official NIH RePORTER page below.