The present invention is methods and devices for improving valve function in a heart. Particularly a device of the present invention comprises a an elongate member having a distal end and a proximal end, a thermal heating member fixed to the distal end of the elongate member, wherein the thermal heating member includes at least one thermal heating element adapted to supply thermal energy to a heart valve structure, and an energy source in communication with the thermal heating element. In use, a thermal heating device of the present invention is inserted into working space proximate the valve to be treated and is used to selectively contract the collagen fibers of the valve structure treated so as to improve the performance and functioning of the valve. Devices are disclosed suitable for use with a variety of access procedures on both beating and non-beating hearts, including: a minimally invasive surgical procedure, a sternotomy, a thoracotomy, an endovascular procedure, and endoscopic procedure, or a percutaneous procedure. Methods and devices are disclosed which are suitable for treatment of a chordae, leaflet, or annulus, as well as devices and methods for the replacement of heart valve with prosthetic valves.