Abstract: Delivery systems (100, 200, 300, 400, 500) including a delivery device (130, 230, 330, 430, 530) having a catheter (132, 133, 232, 233, 332, 333, 432, 433, 532) and a stabilization device (150, 250, 350, 450, 550), the delivery device configured for delivering an apparatus to a left atrium (20) of a patient via the patient's vasculature. The stabilization device has a delivery position in which the stabilization device is collapsed against the catheter and a deployed position in which the stabilization device expands to engage and support the catheter within the vasculature, for example, within the vena cava (14) proximate the right atrium (16). In various embodiments, the delivery device functions as an introducer though which a second delivery device carrying the apparatus is inserted. Methods of accessing the left atrium with the delivery systems and devices are also disclosed.