Patients with atrial fibrillation (AF) are at high risk of stroke. More than 15% of all strokes are due to atrial fibrillation. So far anticoagulation is the treatment of choice with a risk reduction of almost 70%. On the other hand, anticoagulation has many side effects such as intracranial or gastrointestinal hemorrhage. Closing the left atrial appendage (LAA) might be an alternative in patients who cannot take anticoagulation treatment due to contraindications or conditions in which the hazard of hemorrhage is greater than the potential clinical benefit. The PLAATO system (Percutaneous Left Atrial Appendage Transcatheter Occlusion) is a new device to close the LAA by the catheter technique. The device consists of a self-expandable nitinol cage that is covered with ePTFE. It is delivered via a specially designed 12F transseptal sheath. Small anchors along the struts prevent the occluder from embolizing. After device implantation patients are placed on aspirin only. The results of the dog model and the first clinical experiences in humans have been very promising.