Some embodiments of the invention provide a system for occluding a left atrial appendage of a patient. Some embodiments of the system can include a ring occluder that can be positioned around the left atrial appendage and a ring applicator to position the ring occluder with respect to the left atrial appendage. One embodiment discloses a method of accessing endocardial surfaces of the heart through the atrial appendage. Additional embodiments of the invention provide a clip occluder that can be positioned around the left atrial appendage. A clip applicator can position the clip occluder with respect to the left atrial appendage.