ORTHOSTATIC VERSUS ELECTROPHYSIOLOGIC TESTING IN UNEXPLAINED SYNCOPE IN CHILDREN AND ADOLESCENTS

Orthostatic vs EP Testing in Pediatric Unexplained Syncope. Introduction: Unexplained syncope in the pediatric age group is a common problem that often requires cardiac evaluation. This work-up is expensive and frequently unrevealing. Electrophysiologic and, more recently, tilt table or orthostatic testing have been used in the evaluation of unexplained syncope. Methods and Results: We undertook to compare the results of these two forms of evaluation in a group of 26 young patients less than 19 years of age with episodes of unexplained syncope. Sixteen of the 26 patients (62%) had an abnormal electrophysiologic study with the majority having either mild sinus node dysfunction or inducible atrial flutter. Four of the 26 patients (16%) were thought to have an abnormality found that was clinically significant (sustained ventricular tachycardia [2], nonsustained ventricular tachycardia/polymorphic premature ventricular contractions [1], and high-degree atrioventricular block [1]). An abnormal response to orthostatic testing was found in 14 of 26 patients (56%) with 13 of 14 developing syncope at an average standing time of 6.5 minutes. Sixteen patients underwent treatment based on the study findings and follow-up with an average time of 1.6 years is available on 13 of 16 patients who underwent treatment. Of the nine patients treated for neurally mediated syncope (fludrocortisone [7], beta blocker [1], theophylline [1]), all are asymptomatic. The four patients with an arrhythmic cause of syncope found by electrophysiologic testing are asymptomatic on treatment (antiarrhythmic drug [3], permanent pacing [1]). Conclusion: Orthostatic testing has a higher positive yield than electrophysiologic testing in the evaluation of unexplained syncope in young patients. Orthostatic or tilt table testing should be considered early on in the cardiovascular evaluations of these patients.