The invention relates to an implantable quadrupole electrode (1), a multi-sequential neurostimulation of the phrenic nerve, consisting of a matrix provided with two branches (11) and (12) connected by a bridge (13) and provided, each with two contactors (14,15) and (16,17) arranged symmetrically about the axis of said nerve and intended to be powered by a multi-sequential electrical neurostimulation current. The electrode (1) according to the invention is essentially characterized in that each branch (11, 12) is arranged in the form of a hook (111, 121) designed to surround the phrenic nerve and obtain the optimum contact of the contactors (14, 15, 16, 17) with said nerve, each hook having an extension (112, 122), or tongue, intended to pass through the corresponding incision arranged in the pleura； and in that the matrix of the electrode (1) is made of a flexible and flexible material capable of ensuring on the one hand the contact with the nerve without exerting stress on it and on the other hand its insertion, around nerve and through the corresponding incisions made in the pleura, by a torsion of the bridge (13) and a rotation of the branches (11) and (12) relative to each other. L'invention concerne une électrode quadripolaire implantable (1), de neurostimulation multi-séquentielle du nerf phrénique, constituée d'une matrice pourvue de deux branches (11) et (12) reliées par un pont (13) et pourvues, chacune, de deux contacteurs (14,15) et (16,17) disposés symétriquement autour de l'axe dudit nerf et destinés à être alimentés, en courant électrique de neurostimulation multi-séquentielle. L'électrode (1) selon l'invention se caractérise essentiellement en ce que chaque branche (11,12) est agencée en forme de crochet (111, 121) conçu pour entourer le nerf phrénique et obtenir le contact optimum des contacteurs (14,15,16,17) avec ledit nerf, chaque crochet possédant une prolongation (112,122), ou languette, destinée à traverser l'incision correspo
