Abstracts

Nearly 50% of the syncope cases remain unexplained after a complete evaluation, i.e., [ldquo]syncope of unknown origin.[rdquo] Unlike seizures, a psychogenic etiology for refractory syncope is not usually investigated. The purpose of this study was to estimate the frequency of psychogenic pseudosyncope in these patients. Patients referred to our epilepsy center for recurrent syncope-like episodes and negative work-up (brain imaging, EEG, ECG, 2D-ECHO, Holter monitoring, tilt table) underwent EEG-video monitoring with activation by suggestion ([ldquo]induction[rdquo]), similar to what is used for psychogenic seizures. Activation was done in standing or sitting position. The diagnosis of psychogenic pseudosyncope required: 1) activation procedure that triggered the habitual event; 2) fall and limp motionless unresponsiveness with eyes closed; 3) normal EEG before during and after the clinical event. Habitual episodes were triggered in 9/10 (90%) patients. Age ranged from 21 to 60 (mean 36). Illness duration was 6 months to 15 years (mean 4.2 years). Event frequency was 3-4/day to 2/month. EEG showed preserved alpha rhythm before, during and after the clinical event. There were no epileptiform discharges, background suppression or slowing typically seen in syncope, resulting in a definite diagnosis of psychogenic pseudosyncope. Many cases of [ldquo]syncope of unknown origin[rdquo] may represent psychogenic pseudosyncope. Patients with syncope-like events and a negative evaluation should undergo EEG-video monitoring with induction in order to demonstrate a possible psychogenic etiology and avoid further repeated work-up.