DIscontinuation of Anticoagulation Guided by Smartwatch in Post-ablation Patients with Atrial Fibrillation

The DIAMOND-AF trial, an investigator-initiated multicenter study, randomizes 5,694 stroke-free AF patients with a CHA₂DS₂-VA score of 2-6 post-successful ablation to either smartwatch-guided intermittent direct oral anticoagulant (DOAC) therapy (30-day treatment triggered by AF episodes ≥1 hour single or ≥2 hours/24h) or continuous DOAC therapy. The trial assesses the superiority of intermittent DOAC therapy in reducing major bleeding (ISTH) compared to continuous DOAC therapy, and the non-inferiority of intermittent DOAC in preventing thromboembolism (stroke, embolism, and cardiovascular death) over a 48-month follow-up, aiming to tailor anticoagulation strategies in patients with rhythm control achieved through ablation.

The DIAMOND-AF trial is an investigator-initiated, multicenter, randomized open-label study designed to address anticoagulation uncertainty in 5,694 atrial fibrillation (AF) patients with CHA₂DS₂-VA scores 2-6 who maintain sinus rhythm ≥3 months post-ablation. Participants are randomized 1:1 to receive either NMPA-cleared smartwatch-guided intermittent DOAC (30-day DOAC therapy initiated within 24h of photoplethysmography-detected AF recurrence ≥1-hour single episode or ≥2 hours/24h) or continuous DOAC therapy per current guidelines. The co-primary endpoints evaluate: 1) superiority in reducing ISTH-defined major bleeding events over 48 months, and 2) non-inferiority in preventing composite thromboembolism (ischemic stroke, systemic embolism, and cardiovascular death). Endpoints were assessed through blinded endpoint adjudication committees. This trial pioneers an individualized medicine approach by integrating consumer-grade wearable technology with dynamic anticoagulation, potentially tailoring post-ablation management for high-risk AF populations through dual validation of both arrhythmia detection accuracy (PPG vs ECG) and event-driven anticoagulation efficacy.

Eligibility Criteria:
Inclusion Criteria:

1. Age 18-80 years.
2. No recurrence of atrial arrhythmia within 3 months after the most recent AF/atrial flutter catheter ablation.
3. CHA₂DS₂-VA score of 2-6.
4. Voluntarily sign informed consent to participate in the study.
5. Willingness and ability to comply with the study protocol.

Exclusion Criteria:

1. Non-compliance with prescribed DOACs or antiarrhythmic drugs (AADs), or failure to undergo protocol-mandated 24-hour Holter monitoring for rhythm assessment within 3 months post-ablation.
2. Premature atrial complex or premature ventricular complex burden \>10% on any 24-hour Holter within 3 months after ablation.
3. Moderate-to-severe mitral stenosis (mitral valve area ≤ 2.0 cm²) or mechanical heart valves.
4. History of stroke, transient ischemic attack, systemic embolism, or left atrial thrombus.
5. Conditions associated with an increased risk of bleeding:

   1. History of major non-traumatic bleeding events (e.g., intracranial, intraocular, retroperitoneal, gastrointestinal, or intra-articular bleeding), unless reversible causes have been permanently eliminated;
   2. Untreated intracranial aneurysms, vascular malformations, or gastrointestinal ulcers;
   3. Surgery involving general anesthesia within the last 3 months or planned surgery within the next 3 months;
   4. Bleeding disorders (e.g., hemophilia);
   5. Uncontrolled hypertension (systolic BP \> 180 mmHg or diastolic BP \> 110 mmHg);
   6. Hemoglobin \< 90 g/L or history of blood transfusion within 4 weeks prior to enrollment;
   7. Severe thrombocytopenia (platelet count \< 50 × 10⁹/L);
   8. Stage 5 chronic kidney disease (eGFR \< 15 ml/min/1.73m²) or dialysis;
   9. Severe liver disease (e.g., esophageal varices, ascites, hepatic encephalopathy, or jaundice);
   10. Known intolerance or contraindications to DOACs.
6. Presence of a cardiac implantable electronic device or indication for a permanent pacemaker, implantable cardioverter-defibrillator (ICD), or cardiac resynchronization therapy (CRT).
7. Conditions requiring long-term anticoagulation (e.g., pulmonary embolism, deep vein thrombosis, hypertrophic cardiomyopathy, or amyloidosis).
8. High risk for non-cardiogenic stroke (e.g., carotid artery stenosis \> 70%).
9. Currently on warfarin and unwilling or unable to switch to a DOAC.
10. Currently on dual antithrombotic therapy (e.g., dual antiplatelet therapy or anticoagulant plus antiplatelet therapy).
11. Left atrial appendage (LAA) occlusion, LAA closure, or confirmed LAA electrical isolation.
12. Woman who is pregnant and/or breastfeeding.
13. Life expectancy of less than 2 years.
14. Presence of tattoos, birthmarks, surgical scars, or tremors (e.g., Parkinson's disease, benign essential tremor) in the wrist area that may interfere with PPG monitoring.
15. Participation in another interventional clinical trial.
16. Any condition that, in the investigator's judgment, makes the participant unsuitable for the study.