A device for providing cardiac treatment at the left atrium of a patient's heart. The device includes a retention body and a prosthetic valve. The retention body has a shape that can be manipulated between a collapsed state and a normal or expanded state. First and second openings are defined at one side of the retention body, and a lower opening is defined at an opposite side. The prosthetic valve is carried by the retention body at the lower opening. The retention body is configured to engage a substantial portion of an interior surface of the left atrium, securing the prosthetic valve at a desired location relative to a native mitral valve (e.g., within the mitral valve or slightly spaced from the mitral valve). The first and second openings are sized and shaped so as to permit blood flow from the pulmonary veins into the interior region.
