Unexplained Syncope Evaluated by Electrophysiologic Studies and Head-up Tilt Testing

Authors:
  • AAAlfred J. Anderson
    Alfred J. Anderson
  • SSShabbir H. Sheikh
    Shabbir H. Sheikh
  • BABoaz Avitall
    Boaz Avitall
  • PTPatrick J. Tchou
    Patrick J. Tchou
  • PTPaul J. Troup
    Paul J. Troup
  • CGCarol J. Gilbert
    Carol J. Gilbert
  • MAMasood Akhtar
    Masood Akhtar
  • MJMohammad R. Jazayeri
    Mohammad R. Jazayeri
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Abstract
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.
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