CLINICAL INTRODUCTION

A 36-year-old woman was referred to our neurological and cardiological services with recurrent blackouts. She was diagnosed at age 6 with nocturnal generalised tonic-clonic seizures, which settled by age 13 with Carbamazepine. During adulthood, her seizures were thought to have recurred, but now occurred upon rising up from bed and were preceded by palpitations, breathlessness and light-headedness. Having passed out, she would often bite her cheek, lose urinary continence and was seen to convulse. Upon termination, she would recover rapidly without a clear postictal phase. Our patient's grandmother died suddenly of an unknown cause at age 44.

Neurological investigations showed a normal EEG and …