EEG is very limited in patients presenting with syncope. It provides diagnostic information in less than 2% of patients, almost all of whom have symptoms suggestive of seizure or a history of a seizure disorder. In 79% of patients undergoing Holter monitoring, brief arrhythmias or no arrhythmias are found, and there is no clear link between arrhythmia and syncope or symptoms of presyncope (arrhythmias cannot be excluded in these patients).2 Event monitors are significantly more likely to establish or exclude arrhythmia as a cause of syncope than Holter monitor, but they still have significant limitations (eg, lack of an event during monitoring, inability of patient to activate device). EP studies are abnormal mainly in patients with structural heart disease or an abnormal ECG. While it is true that the presence of late potentials on SAGE has a high sensitivity and specificity for inducible ventricular tachycardia during EP testing, SAGE is of limited value in a work-up. A normal SAGE may help avoid EP studies if ventricular tachycardia is the only concern; however, it is more likely that other arrhythmias are in the differential diagnosis during work-up, often necessitating EP testing. Upright tilt-table testing is useful in evaluating vasovagal syncope and is indicated in patients with recurrent unexplained syncope in whom arrhythmias are unlikely or have been ruled out.
- An EEG is a good screening tool and should be performed routinely to rule out seizure.
2. Kapoor WN, McAdams DJ. Syncope. In: Wachter RM, Goldman L, Hollander H, editors. Hospital medicine. 2nd ed. Philadelphia: Lippincott Williams & Wilkins; 2005:
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