Implantable medical device with a non-traumatic helical anchoring screw

An implantable medical device adapted to be implanted into a thin heart wall of a patient, in particular into an atrial wall comprising successively an endocardium, a myocardium and a visceral pericardium, the device comprising:

• a device body with a front face at its distal end;
• and
• a means for anchoring the medical device to said heart wall,
• wherein the means for anchoring includes a screw with a helix wire wound into a plurality of non-contiguous turns, the screw having a clamped end integral with the front face of the device body and a free end comprising a beveled end defined by at least one oblique surface,
• wherein:
• the normal to the oblique surface of the beveled end is directed away from the front face of the device body, in such a way that the oblique surface is directed towards the heart wall,
• the normal to the oblique surface forms an angle between 30° and 60° with respect to the helix axis, and
• the screw is elastically deformable in axial compression, wherein the screw is a non-piercing screw devoid of tip or cutting edge, and wherein:
• the oblique surface has at its end a rounded edge adapted to slide over the visceral pericardium without piercing it,
• the length of the active turns of the screw is lower than 1.5 mm, and the stiffness coefficient K of the screw in axial compression is at most 5 N/mm, so that, during an implantation in an atrial wall, the screw, after having reached the visceral pericardium, produces a crushing of the myocardium without piercing the visceral pericardium,
• whereby avoiding any blood effusion in the pericardial space.