Left atrial appendage closure (LAAC) was approved by the ESC guidelines as a stroke prevention alternative to warfarin for patients with nonvalvular atrial fibrillation in patients at high risk of bleeding (IIbB).

Although the overall LAAC benefice, in term of prevention of stroke or embolisme and decresing the anticoagulant-related risk of bleeding is already demonstrated, however the procedure success and safety, critically depends on understanding LAA anatomy and adequate pre-procedure planning.

3D-printed patient-specific adaptive and flexible LA models have demonstrated in a previous study an improving in LAAO device sizing, a better pre-procedural planning of the optimal trans-septal puncture site, by incorporating all anatomical variations and an improuving patient outcomes by reducing procedure time and number of prostheses employed per patient.

This technique is now used in several surgical centers in France and large prospective evaluation of the practice is necessary.

The 3D printing has modified the LAAC practices with a preoperative time allowing an optimal preparation of the prosthesis. This technique is now used in several surgical centers and prospective evaluation of the practice is necessary.

The objective of our research is to demonstrate the reduction of the operating time and number of prosthesis used per procedure when prior LAAC simulation testing and sizing is made on a 3D printed model.

It is therefore a longitudinal research to monitor professional practices for the evaluation of a new preoperative approach.

Procedures guided by 3Dprinted models will be compared (intention to treat population) in term of procedural parameters (procedure time, success rate, number of prosthesis per procedure) and procedural complication with prior Watchman study: post-FDA Approval US experience and national registries data. A second analysis (per protocol population) will be performed to compare patients with an informative utilization guided by 3D printed to those of the post-FDA Approval US experience and national registries.

Inclusion Criteria:

• non valvular AF
• adressed for LAAC procedure

Exclusion Criteria:

• opposition from patients

Patients in atrial fibrillation addressed for percutaneous left atrial appendage closure intervention