Prospective Smartwatch Study on Surgical Ablation Success in Atrial Fibrillation

All articles of this category (opens in new window) Background: Atrial fibrillation (AF) is highly prevalent among patients undergoing cardiac surgery. Although supported by current guidelines, the application of surgical ablation remains inconsistent. Furthermore, there is a notable lack of structured follow-up data regarding surgical ablation. Smartwatches can detect AF in early stages, yet the possibilities of these devices are not yet being fully utilized. Methods: This single-center study includes all patients undergoing concomitant surgical ablation at the German Heart Center since July 2023. Surgical ablation techniques are the Cox–Maze–IV procedure or radiofrequency box lesion sets of the pulmonary veins. All patients meeting the technical requirements receive a smartwatch. Patients are evaluated 3, 6, and 12 months postoperatively regarding survival, major adverse cardiac and cerebrovascular events (defined as death, myocardial infarction, stroke, and major bleeding), freedom from AF, quality of life, and the accuracy of smartwatch electrocardiogram (ECG) in comparison to Holter ECG. Results: An interim analysis in August 2025 included 61 consecutive patients (age 65 ± 8 years). Seventy-seven percent were male, and 27 patients received a smartwatch. Cox-Maze-IV-Procedure was performed in 78.6% ( n = 48), and box lesion sets in 21.4% ( n = 13). Concomitant procedures were mitral valve surgery 68.9% ( n = 42), thereof mitral valve repair was 41% ( n = 25), replacement was 27.9% ( n = 17), aortic valve surgery was 31.1% ( n = 19), and aortic surgery was 6.6% ( n = 4). Left atrial appendage closure was performed in 100% ( n = 61). Major bleedings were seen in 6.4% ( n = 4), perioperative stroke in 1.6% ( n = 1). Survival was 100% at 30 days, as well as at the last follow-up. At discharge, sinus rhythm (SR) was present in 53.4% ( n = 31/58) of patients. The 3-month follow-up period has been completed by 37 patients, showing an increase of 81.0% ( n = 30/37) in SR. At 6-month follow-up, 84.6% ( n = 22/26) were in SR, and after 12 months, 76.5% of patients ( n = 13/18) were in SR. The compliance of patients in using the smartwatch was 93% ( n = 25/27). The accuracy of smartwatch ECG compared to Holter ECG was 91.8% ( n = 56), correct detection of SR 97.9% ( n = 46), and of AF 71.4% ( n = 10). Conclusion: Surgical ablation offers excellent rates of conversion to SR within 12 months postoperatively, while major perioperative complications are rare. Reliable smartwatch ECG monitoring enables patient-driven follow-up with strong diagnostic accuracy and excellent compliance, supporting efficient long-term care. Publication History Article published online: 17 February 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany