Abstract: An implantable direct cardiac compression (DCC) device (101) has a body (102) comprising a flexible frontal cardiac compression wall (103) and a rear wall (104) together defining a pressurisable chamber (106). The cardiac compression wall (103) is adapted to be affixed to the wall of a ventricle (21) of a heart (20) and to compress the ventricle (21) upon pressurisation of the chamber (106). The device (101) is provided with two flexible flaps, one extending from each of two of opposing lateral sides of the body (102), adapted to be affixed to the ventricle wall (23). An implantable DCC system comprises left and right DCC devices (101, 201) for affixing to the left and right ventricles (21, 22). Straps (216) are provided on the right DCC device (206) for wrapping around the heart (2) and left DCC device (101) to secure the DCC devices (101, 201) to the left and right ventricles (21, 22) respectively.