The diagnosis of epilepsy is complicated by various conditions that can mimic an epileptic seizure. Many patients with abnormal seizure activity during loss of consciousness may have cardiovascular syncope with global cerebral hypoxia (convulsive syncope), which may be difficult to differentiate from epilepsy on clinical grounds. The differentiation is, however, important because they need quite different treatment modalities. In addition, long-term anticonvulsant therapy is expensive and can cause serious morbidity. The authors present a case of a patient thought to have treatment-resistant epilepsy for years with recurrent seizure-attacks, who were subsequently found to have a malignant vasovagal reaction of 24s-asystole as a cause for the so called convulsive syncope. A simple, non-invasive evaluation of circulatory responses to acute orthostasis, the head-up tilt table test, can identify cardiovascular reflex abnormalities in patients with recurrent idiopathic seizure-like episodes. The authors could also reproduce the symptoms of the spontaneous attacks in their patient by this way, to confirm an alternative diagnosis of malignant vasovagal reaction and convulsive syncope in this patient with "refractory epilepsy". This rare cardioinhibition can be safely treated by dual-chamber pacemaker implantation, alleviating for the convulsive attacks, this therapeutic option was advised to this patient as well. Orthostatic stress tests should be considered early in the diagnostic workup of patients with convulsive blackouts. Cardiac causes of loss of consciousness should be considered in patients with presumed epilepsy, atypical premonitory symptoms, non-diagnostic electroencephalograms and failure to respond to anticonvulsant therapy.