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.