Clinical investigation with CE-marked medical devices, multicenter, prospective, randomized and controlled. Patients with non-valvular atrial fibrillation at high embolic risk and with at least one high bleeding risk criterion according to the Munich consensus document will be randomized to left atrial appendage closure with either the Amplatzer Amulet™ or the LAmbre™ device. The study is designed to compare the efficacy and safety of both devices regarding successful implantation, effective appendage closure, and clinical outcomes at follow-up.