This is a randomized controlled trial evaluating atrial fibrillation (AF) detection through smartwatch-based screening in high-risk patients using an Apple Watch with integrated PPG and ECG functions.

This is a multicenter randomized controlled trial evaluating whether six months of heart rate and rhythm monitoring with a smartwatch (Apple Watch Series 5 or 8) equipped with photoplethysmography (PPG) and ECG functions increases atrial fibrillation (AF) detection in high-risk cardiac patients (age ≥65, CHA₂DS₂-VASc ≥2 for men, ≥3 for women) without previously known AF.

Patients are randomized to either smartwatch-based monitoring or standard care. Participants in the intervention group receive an Apple Watch paired with a smartphone app and are instructed to wear the device for at least 12 hours per day. Continuous rhythm monitoring is performed using PPG, with ECGs recorded upon symptom onset or irregular rhythm detection. ECG data are transmitted via the app to a secure platform and reviewed within 24 hours by an independent eHealth team supervised by a cardiologist. Patients and their treating physicians are notified upon new AF diagnoses.

To evaluate the primary endpoint, a total of 218 patients per arm were required according to the sample size calculation.

Inclusion Criteria:

• Age ≥ 65 years
• Chadsvasc score ≥2 for men and ≥ for women at the time of eligibility screening
• Written informed consent as documented by signature from the participant
• Possession of iPhone (6S or later)

Exclusion Criteria:

• Diagnosis of atrial fibrillation or atrial flutter
• Currently on anticoagulation therapy
• Cardiac implanted electronic device (pacemaker, ICD)
• Smartwatch cannot be worn due to comprehensible reasons (allergic reactions, wounds, amputations, other)
• Significant mental or cognitive impairment