Abstract: The present disclosure is directed to materials, devices, and methods for treatment of cardiac conditions including, for example, cardiomyopathy and valvular insufficiency. The devices and methods are directed to constraining expansion of the heart during diastole to a predetermined limit. In one embodiment, a material of the invention is a weave material that can be applied to the heart as a wrap of a two-dimensional sheet or shaped into a jacket. A cardiac reinforcement device of the invention can be applied to the heart to constrain cardiac expansion to a predetermined limit.