title: Diagnosing syncope. Part 2: Unexplained syncope. Clinical Efficacy Assessment Project of the American College of Physicians.
abstract: OBJECTIVE
  To review the literature on diagnostic testing in syncope that remains unexplained after initial clinical assessment.
  
  
  METHODS
  MEDLINE search.
  
  
  METHODS
  Published papers were selected if they addressed diagnostic testing in syncope, near syncope, or dizziness.
  
  
  METHODS
  Studies were identified as population studies, referral studies, or case series.
  
  
  RESULTS
  After a thorough history, physical examination, and electrocardiography, the cause of syncope remains undiagnosed in 50% of patients. In such patients, information may be derived from the results of carefully selected diagnostic tests, especially 1) electrophysiologic studies in patients with organic heart disease, 2) Holter monitoring or telemetry in patients known to have or suspected of having heart disease, 3) loop monitoring in patients with frequent events and normal hearts, 4) psychiatric evaluation in patients with frequent events and no injury, and 5) tilt-table testing in patients who have infrequent events or in whom vasovagal syncope is suspected. Hospitalization is indicated for high-risk patients, especially those with known heart disease and elderly patients.
  
  
  CONCLUSIONS
  A flexible, focused approach is required to diagnose syncope. Features of the initial history and physical examination help guide diagnostic testing.
authors.affiliation: University of Wisconsin School of Medicine, Department of Medicine, Madison 53792-2454, USA.
authors.forename: M
authors.initials: M
authors.lastname: Linzer
authors.forename: E H
authors.initials: EH
authors.lastname: Yang
authors.forename: N A
authors.initials: NA
authors.lastname: Estes
authors.forename: P
authors.initials: P
authors.lastname: Wang
authors.forename: V R
authors.initials: VR
authors.lastname: Vorperian
authors.forename: W N
authors.initials: WN
authors.lastname: Kapoor
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D004452:Echocardiography; D015716:Electrocardiography, Ambulatory / Q000379:methods; D004594:Electrophysiology; D005080:Exercise Test; D006331:Heart Diseases / Q000150:complications / Q000175:diagnosis; D006801:Humans; D008875:Middle Aged; D012307:Risk Factors; D013575:Syncope / Q000209:etiology* / Q000523:psychology; D018667:Tilt-Table Test