In this edition of the Journal, Cheung et al. report 2 successful deployments of a catheter-mounted valve for treatment of severe functional mitral valve regurgitation. Both procedures used a novel bovine pericardial valve designed for mitral valve replacement, which was mounted on a self-expanding nitinol frame and advanced through the cardiac apex via surgical cut down. Because of the mitral valve's intricate pathoanatomy and lack of a rigid landing zone, this transcatheter mitral valve prosthesis has a complex design, including anchoring mechanisms to prevent migration into the atrium during ventricular contraction. The prosthesis is not a symmetrical tube but conforms to the typical D-shape of the mitral valve annulus. In contrast, transcatheter aortic valve replacement (TAVR) prostheses have a simple, symmetrical design, with no need for ventricular anchors or specific orientation. Although prosthesis development and technical execution of transcatheter mitral valve replacement (TMVR) present unique challenges, these 2 patients with successfully deployed catheter mitral valves demonstrate that these challenges are not insurmountable. Cheung et al. are to be congratulated for their pioneering effort, which serves as a proof-of-concept for transcatheter replacement in the noncalcified mitral valve. This makes it probable that routine application of TMVR will be technically possible in the near future, leading the authors to question whether TMVR will revolutionize therapy for mitral valve disease, mirroring the course of TAVR.