ISSUE3: International Study on Syncope of Uncertain Etiology 3

Inclusion Criteria: * Suspected or certain neurally-mediated syncope, based on the Guidelines recently published by the Task Force on Syncope of the European Society of Cardiology 2,3 (Appendix 1); * More than 3 syncope episodes in the last 2 years; * Clinical presentation of syncope of sufficient severity requiring treatment initiation in the physician's and patient's judgement. * Age \> 40 years. * Negative carotid sinus massage. * Patients accept to have an ILR implantation. Exclusion criteria: * Carotid sinus hypersensitivity * Suspected or certain heart disease and high likelihood of cardiac syncope: * Symptomatic orthostatic hypotension diagnosed by standing blood pressure measurement; * Loss of consciousness different from syncope (e.g. epilepsy, psychiatric, metabolic, drop-attack, TIA, intoxication, cataplexy); * Subclavian steal syndrome; * Psychologically or physically (due to any other illness) or cognitively unfit for participation in the study according to the opinion of the investigator; * Patient compliance doubtful; * Patient geographically or otherwise inaccessible for follow-up; * Patient unwilling or unable to give informed consent; * Life expectancy \<1 year.