A hybrid system forming an active implantable medical device includes a subcutaneous autonomous capsule and at least one intracorporeal autonomous leadless capsule. The subcutaneous capsule is a hybrid capsule having a seal body of dimensions comparable to those of a leadless capsule, but extended by a detection/stimulation microlead, without any intermediate connector. The leadless capsule includes a seal body, anchoring means in a wall of an organ and a detection/stimulation electrode. The hybrid capsule and the leadless capsules each include transmitter/receiver means for intracorporeal mutual wireless communication so as to constitute a network wherein the hybrid capsule is the master and leadless capsules are the slaves. The hybrid capsule further includes means for centralizing data transmitted by the leadless capsules and for exchanging data with remote external equipment.