Diagnosis of Atrial Fibrillation in Postoperative Thoracic Surgery Using a Smartwatch

Inclusion Criteria: * Adults (\>18 years old). * Patients undergoing major thoracic surgery with one-lung ventilation within the past 48 hours. * Scheduled pneumonectomy or lobectomy. * Admission to a conventional surgical unit postoperatively. * Ability to perform single-lead ECG using a smartwatch. * Coverage under a social security system. * Signed informed consent Exclusion Criteria: * History of atrial fibrillation. * Requirement for telemetry for AV block or tachyarrhythmias (\>140 bpm). * Dependency on a pacemaker. * Participation in another interventional clinical trial affecting POAF incidence. * Mediastinal, pleural, or chest wall surgery. * Reoperations or surgeries performed more than 48 hours prior. * Pregnant women. * Patients under guardians or similar legal protection.