A toolkit for implanting an intracorporal lead, preferably a cardiac sensing / pacing lead. This toolkit includes a guide-catheter (10), having a sheath (12) with an internal lumen (42) opened at its distal and proximal ends, and cuttable along a generatrix in order to allow extracting of the guide-catheter after use. A hemostatic valve (14) is mounted at the proximal end (40) of the guide-catheter, for selectively filling, or not, the internal lumen of the guide-catheter at its input end. The valve is frangible in at least two parts, each dissociable from the guide-catheter at both sides around a median axial plane. The valve comprising a mobile element sliding on the guide-catheter between two extreme positions, with an opened position where the proximal end (40) of the guide-catheter (10) freely emerges out of the valve so as to allow access to said internal lumen, and a closed position where this proximal end of the guide-catheter is filled in a tight manner.