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.