The Rhythm Evaluation for AntiCoagulaTion With Continuous Monitoring of Atrial Fibrillation

Inclusion Criteria:

1. 22-85 years of age.

2. English speaking participants. Spanish-only speakers may be included in the futureat select sites appropriately translated.

3. History of non-permanent atrial fibrillation.

4. CHA2DS2-VASC score of 1-4 for men and 2-4 for women without prior stroke orTransient Ischemic Attack (TIA), The CHA2DS2-VASc score is a point-based system usedto stratify the risk of stroke in Atrial Fibrillation (AF) patients. The acronymCHA2DS2-VASc stands for congestive heart failure, hypertension, age ≥75 (doubled),diabetes, stroke (doubled), vascular disease, age 65 to 74 and sex category (female). Congestive heart failure defined as: The presence of signs and symptoms ofeither right (elevated central venous pressure, hepatomegaly, dependent edema) orleft ventricular failure (exertional dyspnea, cough, fatigue, orthopnea, paroxysmalnocturnal dyspnea, cardiac enlargement, rales, gallop rhythm, pulmonary venouscongestion) or both, confirmed by non-invasive or invasive measurementsdemonstrating objective evidence of cardiac dysfunction and/or ejection fraction < 40%.

5. The participant is on a DOAC at the time of screening and willing to stay on DOACfor duration of study.

6. Willing and able to comply with the protocol, including:

• Possession of a smart watch-compatible smart phone (iPhone that supports thelatest shipping iOS) with a cellular service plan

• Be willing to wear the smart watch for the suggested minimum of 14 hours a day

• Expected to be within cellular service range at least 80% of the time

7. Willing and able to discontinue DOAC

8. The participant is willing and able to provide informed consent.

Exclusion Criteria:

1. Valvular or permanent atrial fibrillation.

2. Current treatment with warfarin and unwilling or unable to take a DOAC.

3. The participant is a woman who is pregnant or nursing.

4. The participant is being treated with chronic aspirin, another anti-platelet agent,or chronic NSAIDS outside of current medical guidelines (e.g., primary strokeprevention in patients with atrial fibrillation, primary prevention ofcardiovascular events, pain relief, fever, gout) and is unwilling or unable todiscontinue use for the study duration.

5. Existing cardiac rhythm device or indication for a permanent pacemaker, ImplantableCardioverter-Defibrillator (ICD) or Cardiac Resynchronization Therapy (CRT) deviceor planned insertable cardiac monitor. Insertable cardiac monitors are permittedunless they are being used to guide anticoagulation treatment.

6. Known or suspected symptomatic or asymptomatic atrial fibrillation lasting ≥ 1hour/month over the last 3 months.

7. Any documented single AF episode lasting ≥ 1 hour on standard of care orstudy-provided external cardiac monitor of > 6 days duration performed within 45days prior to randomization. Shorter monitoring durations may be acceptable forinclusion at the discretion of the site PI based on the totality of monitoring dataand approval of the study PI.

8. Ablation for AF within the last 2 months.

9. Prior or anticipated left atrial appendage occlusion or ligation.

10. Mechanical prosthetic valve(s) or severe valve disease.

11. Hypertrophic cardiomyopathy.

12. Participant needs DOAC for reasons other than preventing stroke or arterial embolismresulting from AF (i.e., preventing Deep Vein Thrombosis (DVT) or PE) or needspermanent OAC (i.e., congenital heart defects, prosthetic heart valve).

13. Participants deemed high risk for non-cardioembolic stroke (i.e., significantcarotid artery disease defined as stenosis > 75%) based on the investigator'sdiscretion.

14. The participant is enrolled, has participated within the last 30 days, or isplanning to participate in a concurrent drug and/or device study during the courseof this clinical trial. Co-enrollment in concurrent trials is only allowed withdocumented pre-approval from the study manager; there is no concern thatco-enrollment could confound the results of this trial.

15. The participant has a tattoo, birthmark, or surgical scar over the dorsal wrist areaon the ipsilateral side that the AFSW may be worn.

16. The participant has a tremor on their ipsilateral side that the AFSW may be worn.

17. Any concomitant condition that, in the investigator's opinion, would not allow safeparticipation in the study (e.g., drug addiction, alcohol abuse).

18. Known hypersensitivity or contraindication to direct oral anticoagulants.

19. Documented prior stroke (ischemic or hemorrhagic) or transient ischemic attack.

20. Reversible causes of AF (e.g., cardiac surgery, pulmonary embolism, untreatedhyperthyroidism). AF ablation does not constitute reversible AF.

21. > 5% burden of premature atrial or ventricular depolarizations on pre-enrollmentcardiac monitoring.

22. History of atrial flutter that has not been treated with ablation (participants inatrial flutter and have been ablated are eligible for enrollment).

23. Stage 4 or 5 chronic kidney disease.

24. Conditions associated with an increased risk of bleeding:

• Major surgery in the previous month

• Planned surgery or intervention in the next three months that would requirecessation of anticoagulation > 2 weeks.

• History of intracranial, intraocular, spinal, retroperitoneal, or atraumaticintra- articular bleeding

• Gastrointestinal hemorrhage within the past year unless the cause has beenpermanently eliminated (e.g., by surgery)

• Symptomatic or endoscopically documented gastroduodenal ulcer disease in theprevious 30 days

• Hemorrhagic disorder or bleeding diathesis

• Need for anticoagulant treatment for disorders other than AF

• Uncontrolled hypertension (Systolic Blood Pressure >180 mmHg and/or DiastolicBlood Pressure >100 mmHg)