Epilepsy or syncope? An analysis of 55 consecutive patients with loss of consciousness, convulsions, falls, and no EEG abnormalities.

BACKGROUND: Patients with loss of consciousness and convulsion often have the diagnosis of epilepsy despite normal electroencephalograms (EEGs).
OBJECTIVE: To evaluate the proportion of patients referred to neurologists with presumed epilepsy and normal EEGs who have an alternative cause of syncope.
METHODS: It was a cross-sectional study of 55 consecutive patients aged 6-85 (41 +/- 24) years presenting with faints, falls, convulsions, and normal EEGs, who were referred to neurologists before going to cardiologists. All patients underwent clinical examination, electrocardiogram, and echocardiogram. Head-up tilt table testing (HUT), 24-hour-Holter, and carotid sinus massage was offered as needed. Electrophysiological studies were undertaken in patients with structural heart disease or severe palpitations.
RESULTS: Anticonvulsant agents had been prescribed to 35 patients (64%) before entering the study. Vasovagal syncope was found in 22 (40%) patients, life-threatening arrhythmias in seven (13%), carotid sinus hypersensitivity in six (11%), orthostatic hypotension in three (5%), and aortic stenosis in one (2%). Etiology of syncope could not be found in 16 (29%) patients. Arrhythmias comprised two complete atrioventricular blocks, one sustained monomorphic ventricular tachycardia, one ventricular fibrillation, one atrial tachycardia, and two atrioventricular node reentrant tachycardias. Two patients developed a prolonged asystole during HUT. Presumptive diagnosis of syncope was found in 39 patients (71%). Patients on or off anticonvulsant drugs had 64% and 84% diagnosis of syncope, respectively (odds ratio = 0.33; 95% confidence interval 0.08-1.36; P = 0.13).
CONCLUSIONS: Life-threatening arrhythmias and syncope can be present in patients with presumed epilepsy and normal EEG. Prescription of anticonvulsant agents in these patients should wait for a cardiovascular assessment.