Unexplained syncope evaluated by electrophysiologic studies and head-up tilt testing

• Published in: Annals of internal medicine Vol. 114; no. 12; p. 1013
• Main Authors: Sra, J S, Anderson, A J, Sheikh, S H, Avitall, B, Tchou, P J, Troup, P J, Gilbert, C J, Akhtar, M, Jazayeri, M R
• Format: Journal Article
• Language: English
• Published: United States 15.06.1991
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; Arrhythmias, Cardiac - complications; Arrhythmias, Cardiac - diagnosis; Bradycardia - diagnosis; Child; Electrodiagnosis - methods; Female; Follow-Up Studies; Humans; Isoproterenol; Male; Middle Aged; Posture; Syncope - etiology; Tachycardia - diagnosis; Tachycardia, Supraventricular - diagnosis
• ISSN: 0003-4819
• DOI: 10.7326/0003-4819-114-12-1013

To determine the clinical characteristics of subgroups of patients with unexplained syncope having electrophysiologic studies and head-up tilt testing and to assess the efficacy of various therapies. Retrospective study. Inpatient services of a tertiary referral center. Eighty-six consecutively referred patients with unexplained syncope. All patients had electrophysiologic examinations. Patients with negative results subsequently had head-up tilt testing. Twenty-nine (34%) patients (group 1) had abnormal electrophysiologic results, with sustained monomorphic ventricular tachycardia induced in 72%. Thirty-four (40%) patients (group 2) had syncope provoked by head-up tilt testing. The cause of syncope remained unexplained in 23 (26%) patients (group 3). Structural heart disease was present in 76%, 6%, and 30% of groups 1, 2, and 3, respectively. In group 1, pharmacologic or nonpharmacologic therapy was recommended based on electrophysiologic evaluation. All group 2 patients had negative results on head-up tilt testing while receiving oral beta blockers (27 patients) or disopyramide (7 patients). Group 3 patients did not receive any specific therapy. During a median follow-up period of 18.5 months, syncope recurred in 9 (10%) patients. The combination of electrophysiologic evaluation and head-up tilt testing can identify the underlying cause of syncope in as many as 74% of patients presenting with unexplained syncope. Therapeutic strategies formulated according to the results of these diagnostic tests appear to prevent syncope effectively in most patients.