Functional mitral regurgitation (MR) in heart failure patients limits survival in a severity-graded fashion. Even mild MR doubles the mortality risk. The use of a nonstented coronary sinus device to reduce mitral annulus dimension in order to reestablish mitral valve competence is reported. The device (PTMA, Viacor, Inc., Wilmington, MA, USA) consists of a multilumen PTFE (Teflon) PTMA catheter in which nitinol (nickel-titanium alloy) treatment rods are advanced. For individual treatment, up to three rods of different length and stiffness can be used. Therefore, dimension reduction can be performed in an incremental fashion. Fluoroscopy and three-dimensional (3-D) echocardiography are performed through the procedure to visualize the positioning and confirm maximum treatment effect. This report describes an implant case and summarizes the safety and feasibility of the new PTMA treatment device in 27 patients. The cases reflect the learning curve in both device design and implantation technique. In permanent implant, a sustained reduction of mitral annulus septal-lateral dimension from 3-D echo reconstruction dimensions was observed (4.9 +/- 1.2 mm at 3 months).