Atrial Fibrillation (AF) is the most common cardiac arrhythmia worldwide, affecting approximately 2.8% of the population, with prevalence increasing with age. AF is associated with significant morbidity and mortality, accounting for about 25% of ischemic strokes, 10% of cryptogenic strokes, and a 10-40% annual increase in hospital admissions due to heart failure or anticoagulant-related events.

About 10% of patients undergoing cardiac surgery have preoperative AF. In 1986, Dr. Cox introduced the MAZE procedure, a surgical technique to isolate AF triggers. Initially involving atrial incisions, it evolved to use radiofrequency lines, significantly reducing morbidity and mortality. The MAZE procedure is now strongly recommended (Class Ia evidence) for concomitant cardiac surgery. However, nearly 85% of eligible patients-especially those undergoing closed-chest cardiac surgery-do not receive this treatment due to technical challenges and limited reproducibility of the Cox-Maze IV technique.

Pulmonary Vein Isolation (PVI) with posterior wall isolation (PWI-Box) has emerged as an effective alternative, offering similar outcomes to Cox-Maze IV with fewer adverse effects. Innovative devices like the GeminiS (Medtronic) enable minimally invasive, thoracoscopic PVI-PWI-Box procedures without opening the heart, even off-pump. This approach could expand the use of AF ablation during combined sternotomy surgeries, aligning with clinical guidelines.

Primary Objective: Assess the efficacy of PWI-Box using GeminiS combined with other cardiac surgeries via sternotomy.

Primary Endpoint: Recurrence rate of paroxysmal or persistent AF (per ESC definition) at 1 year postoperatively, confirmed by 24-hour Holter monitoring.

Inclusion criteria:

• Patients undergoing cardiac surgery via sternotomy
• Concomitant use of the PWI box with GeminiS during surgery
• Adult patients
• Patients with the following characteristics: Preoperative paroxysmal/persistent/permanent AF; Duration of less than 5 years; And left atrium volume <60 ml/m2
• Informed patient who did not object to the collection of their data for the study

Exclusion criteria:

• Unplanned surgery (emergency)
• History of cardiac surgery (reoperation)
• Pregnant or breastfeeding women
• Adults under guardianship, curatorship or judicial protection
• Patients with a life expectancy of less than three years
• Patients currently taking medication or using an experimental device that clinically interferes with the study's evaluation criteria and results.
• Inability to comply with the monitoring schedule.
• Contraindication to long-term anticoagulants

Patients with a surgical indication for AF in combination with conventional cardiac surgery performed by sternotomy (coronary artery bypass grafting, aortic valve replacement, aortic surgery, etc.). Patients may be included prospectively, via information provided by the attending physician during a consultation (written and oral), or retrospectively for those who have already undergone surgery, by sending an information notice with a non-objection period.