The purpose of this research is to gather information about the effectiveness and safety of Left Atrial Appendage Occlusion (LAAO) device procedures in patients using a Watchman device performed on days where doctors perform a large number of procedures.

The study primary outcome is to evaluate complications during the procedure up to 30 days after the procedure.

The final outcome is to determine successful placement within 31 - 90 days after implant.

This study will compare WATCHMAN FLXTM ("DEVICE") to a category of OAC called non-vitamin K antagonist oral anticoagulation, also known as NOACs ("CONTROL"). NOAC medications include Pradaxa® (dabigatran), Eliquis® (apixaban), Xarelto® (rivaroxaban), or Savaysa® (edoxaban).The study will research the safety and effectiveness of the WATCHMAN FLXTM device compared to treatment with NOAC therapy to determine if it works for patients with your type of atrial fibrillation who require treatment for potential blood clot formation (thrombus) in the LAA.