An intracardiac capsule comprises a cylindrical body having an atraumatic rounded surface and a helical anchoring screw integral with the cylindrical body. The helical anchoring screw is able to penetrate tissue of a wall of the heart and is configured to provide temporary attachment, in rotation and in translation, of the capsule to an implantation site. The helical anchoring screw surrounds at least a portion of the length of the cylindrical body forming a contact region intended to come into contact with the wall of the cavity of the heart. Over the length of the contact region, the external diameter of the cylindrical body is less than the inner diameter of the helical anchoring screw, so as to leave a free gap there between. The helical anchoring screw is secured to the cylindrical body near the proximal end of the contact region, and extends freely to the opposite distal end.