one embodiment the material of the jacket can be made radiopaque by inclusion of radiopaque markers for identification of the outside surface of the heart the expansion slot or inflation port as used herein radiopaque means causing the crd to be visible on x ray or fluoroscopic viewing suitable radiopaque markers include for example platinum wires titanium wires and stainless steel wires a crd according to the present disclosure provides a new method for the treatment of cardiac disease as used herein cardiac disease includes diseases in which dilation of one of the chambers of the heart is a component of the disease examples include heart failure or cardiomyopathy heart failure can occur as a result of cardiac dilation due to ventricular hypertrophy or secondary to for example valvular incompetency valvular insufficiency or valvular stenosis cardiomyopathy according to the invention can be primary or secondary to infection ischemia metabolic disease genetic disorders etc it is foreseen that constraint of cardiac expansion by a device of the invention can provide reduced cardiac dilation reduced cardiac dilation can cause reduction in the problems associated with cardiac dilation such as arrhythmias and valvular leakage as reduction of cardiac dilation occurs selective reduction of the predetermined size of the jacket also provides continued reinforcement for the size reduced heart a crd jacket can also be used to measure cardiac performance according to this embodiment the crd jacket is rendered radiopaque by use of a radiographic marker the radiographic markers are distributed throughout the jacket over the surface of the heart by evaluation of the markers relative to one another with each heart beat cardiac performance may be measured as such.