Syncope during EEG recording.

A 75-year-old man had several syncopes with severe skull contusions (figure 1). These events were not preceded by vegetative symptoms such as nausea, dizziness, or palpitations. Holter-EKG was normal and an EEG was performed for suspected epilepsy, during which complete atrioventricular block without ventricular escape-rhythm occurred (figure 2A). Six seconds later, the EEG showed progressive slowing of background activity and voltage reduction, followed by electrocerebral silence (figure 2B); clinically the patient lost cervical muscle tone and became unconscious. Thirty-three seconds later, sinus-rhythm reoccurred, followed by the return of cerebral activity in reverse manner (figure 2C). The patient regained consciousness instantly and, when addressed by the technician, he was fully responsive (see video clip). A pacemaker was implanted and the patient was free of symptoms. Clinical presentation of syncope does not often allow one to distinguish between cerebrovascular and epileptic origin. Despite normal 24-hour EKG, simultaneous EKG recording is mandatory when EEG is used in the evaluation of syncope.1,2