Atrial Fibrillation represents an important risk of cardioembolic stroke. In more than 90% of cases, thrombus originate in the left atrial appendage. Therefore guidelines recommend the anticoagulation of patients with atrial fibrillation and a significant cardioembolic risk, predicted by the CHA2DS2VASc score.

However, serious bleeding complications may definitively contraindicate the use of anticoagulants.

For those patients, percutaneous Left Atrial Appendage Occlusion (LAAO) has became a recommended alternative to prevent the thrombus formation and reduce the risk of cardioembolic events.

In the CHU of Brest, more than 120 patients have been treated with LAAO for the last 8 years with two different occluder devices : WATCHMAN®, Boston Scientifc and AMPLATZER Amulet®, Abbott Laboratories.

This retrospective longitudinal observational study named CLAPOT (CHU of Brest' Left Atrial Appendage Percutaneous Occlusion Treatment) aims to evaluate the long term results of this procedure for effectiveness and safety and to compare the results between the two devices (Watchman and Amplatzer).

Inclusion Criteria:

• Major
• Non opposition
• All patients with non-valvular atrial fibrillation and a definitive contraindication to anticoagulants who underwent left atrial appendage occlusion in the CHU of Brest between December 2014 and August 2023

Exclusion Criteria:

• Minor
• Patients under tutorship or curatorship
• Formulated opposition

All patients with non-valvular atrial fibrillation and a definitive contraindication to anticoagulants who underwent left atrial appendage occlusion in the CHU of Brest between December 2014 and August 2023

All collected data that underlie results in a publication

Data will be available beginning three years and ending fifteen years following the final study report completion

Data access requests will be reviewed by the internal committee of Brest UH. Requestors will be required to sign and complete a data access agreement