Guidelines for the use of electrophysiologic studies in syncope have not yet been formulated. To confirm the sensitivity and specificity of a previously derived model to predict the results of electrophysiologic testing in syncope, the importance of 6 clinical predictors was assessed in a new data set of 141 consecutive patients with unexplained syncope who were referred for electrophysiologic studies. The 6 predictors were: organic heart disease; premature ventricular beats, sinus bradycardia, first-degree heart block and bundle branch block by electrocardiogram; and nonsustained ventricular tachycardia by Hotter monitor. Organic heart disease and nonsustained ventricular tachycardia by Hotter monitoring were highly sensitive for serious ventricular tachyarrhythmias at electrophysiologic study (sensitivity 100%), whereas sinus bradycardia, first-degree heart block or bundle branch block by electrocardiogram were sensitive for bradyarrhythmic outcomes (sensitivity 79%). Because these variables are so sensitive for serious outcomes of electrophysiologic testing in syncope, invasive studies in patients without these clinical predictors are likely to be of very low diagnostic yield.
Bibliographical noteFunding Information:
From the Syncope Evaluation Center and the Cardiac Arrhythmia Service, Divisions of Cardiology and General Medicine, Department of Medicine, and the Center for Cardiovascular Health Services Research, New England Medical Center, Tufts University School of Medicine, Boston, Massachusetts. This project was supported in part by BRSG Grant 507-RR05598-22 from the Biomedical Research Support Pro gram, Division of Research Resources, National Institutes of Health, Bethesda, Maryland, and was presented in part at the annual meetings of the North American Society of Pacing and Elcctrophysiology, Washington, D.C., in May 1991. Manuscript received August 26, 1991; revised manuscript received December 17,199 1, and accepted Dccem-ber 18.