This is a multi-center, prospective, observational study enrolling 400 patients with suspected or certain neurally-mediated syncope, who undergo carotid sinus massage, tilt testing and Implantable Loop Recorder (ILR)implantation. In its second phase, which starts after the first ILR-documented syncope, the study will register the patient outcome after administration of ILR-guided therapy, which is left to the discretion of the physicians. The main objective is to verify the value of ILR in assessing the mechanism of syncope and the efficacy of the ILR-guided therapy after syncope recurrence.