Medical apparatus, namely, a device consisting of attachment screws, which are implanted in the left ventricle (LV) wall and used as an anchor for the elastic elements and elastic elements comprising metal springs which are anchored between neighboring attachment screws and harness energy produced by the LV during systole and release it during diastole without the need of an external power source or any pumping machinery, all for improving ventricular diastolic function; medical kits consisting of medial elastic metal spring elements assembled in the middle of the LV wall, peripheral elastic metal spring elements assembled on the edges of the LV wall, vertical and horizontal location guides used for vertical and horizontal positioning the device in between upper and lower boundaries of the LV surface, pairs of attachment screws, which are implanted in the LV wall and used as an anchor for the elastic elements, and delivery tools having a hollow outer tube and an inner shaft, which are used for the implantation of the attachment screw to the correct depth in the myocardial tissue; medical kits consisting of long medial and peripheral elastic metal spring elements with various lengths to conform to human heart anatomy, and long horizontal guide for the implantation of the long elastic elements; medical kits comprising delivery tools for implantation of the attachment screws and elastic elements by minimally invasive procedure, namely, a hollow tube with a joint at its end in which the attachment screw is positioned to allow implantation at various angles and a hollow tube in which the elastic element is positioned to allow its implantation between two adjacent attachment screws in a minimally invasive procedure