An autonomous capsule includes a tubular body provided at its distal end with an anchoring screw, and in its proximal region of a capture groove. An explantation accessory includes a reinforced catheter combined with a flexible wire which can slide in the catheter and has a deformable loop which can be clamped by gradual introduction of its ends in the catheter under the effect of a traction exerted on the wire. During tightening, the capture groove receives the wire loop, allowing, after complete tightening, to secure in tension and rotation an assembly formed by the catheter, the capsule, and the wire. The reinforced catheter is then used to transmit a tensile force and an axial torque from its proximal end to its distal end, allowing safe unscrewing of the capsule and its extraction through the patient venous network.
