Study protocol: diagnosis of atrial fibrillation in postoperative thoracic surgery using a smartwatch, an open-label randomised controlled study (THOFAWATCH trial)

Introduction Postoperative atrial fibrillation (POAF) affects approximately 20% of patients undergoing thoracic surgery and is associated with severe complications such as stroke, myocardial infarction, heart failure, and increased mortality. Early diagnosis is critical to mitigate these risks, but conventional monitoring is limited in detecting asymptomatic episodes. Smartwatches equipped with single-lead ECG and atrial fibrillation (AF) detection algorithms offer a novel approach for early POAF detection. This study aims to evaluate the effectiveness of smartwatch-based monitoring compared with standard care in identifying POAF following thoracic surgery. Methods and analysis The THOFAWATCH trial is a randomised, bicentric open-label study enrolling 302 adult patients undergoing major thoracic surgery (pneumonectomy or lobectomy) with one-lung ventilation. Eligible patients will be randomised into two groups: (1) the ‘Smartwatch Monitoring’ group, where participants will undergo rhythm monitoring using a smartwatch and (2) the ‘Conventional Monitoring’ group, receiving standard care without smartwatch monitoring. In the intervention group, any smartwatch-detected POAF episodes will be confirmed by 12-lead ECG. The primary outcome is the incidence of POAF within 7-day postsurgery. Secondary outcomes include the rate of asymptomatic POAF, cardiovascular prognosis evaluated at 2 and 6 months (composite major adverse cardiovascular events outcome), feasibility of smartwatch usage (device usage time and success rate of single-lead ECGs) and recurrence or management of AF at follow-up. Inclusion criteria include adults (>18 years) undergoing scheduled thoracic surgery and able to use the smartwatch device. Exclusion criteria encompass patients with prior AF, those requiring telemetry, or undergoing reoperations. Statistical analysis will assess the primary outcome using χ2or Fisher’s exact test (α=5%), while secondary outcomes will include descriptive and inferential statistics, with analysis conducted using SAS V.9.4. Ethics and dissemination Ethical approval for this bicentric study has been granted by the institutional review board (IRB) of the University Hospital of Amiens (Comité de Protection des Personnes sud-ouest et outre-mer 1, 21050 Toulouse, France, registration number ID RDB: 2022-A02028-27 in November 2024). The trial is registered under ClinicalTrials.gov (ID: ( NCT06724718 )). Results will be disseminated through peer-reviewed publications and scientific conferences to inform clinical practice regarding POAF detection and management following thoracic surgery. Trial registration number NCT06724718 ; clinical trial.