title: Selective use of diagnostic tests inpatients with syncope of unknown cause.
abstract: OBJECTIVE
  We sought to prospectively assess the diagnostic yielding of a protocol in which electrophysiologic studies (EPS), tilt-table tests (TTTs), and loop recorder implantation are selectively used.
  
  
  BACKGROUND
  The optimal strategy in the diagnosis of patients with syncope of unknown cause has not been defined.
  
  
  METHODS
  A total of 184 consecutive patients with syncope of unknown cause were classified into two groups. Group A consisted of 72 patients fulfilling any of the following criteria: 1) presence of structural heart disease or family history of sudden death; 2) abnormal electrocardiogram; 3) significant non-symptomatic arrhythmia on Holter monitoring; and 4) paroxysmal palpitations immediately before or after syncope. These patients initially underwent an EPS and, if this study was negative, TTT. In the remaining 112 patients (group B), TTT was performed.
  
  
  RESULTS
  The EPS was positive in 32 patients (44%) in group A. The TTT was positive in 80 patients (71%) in group B. An additional patient had carotid sinus hypersensitivity. In patients of group A with a negative EPS, the TTT was positive in 23 (57%). A loop recorder was implanted in 15 patients from group A with negative conventional testing, and diagnostic activation was obtained in seven patients. Overall, a positive diagnosis was achieved in 143 patients (78%).
  
  
  CONCLUSIONS
  In patients with syncope of unknown cause, selective use of EPS or TTT leads to a positive diagnosis in >70% of the cases. An implantable loop recorder can be useful in non-diagnosed cases.
authors.affiliation: Department of Cardiology, Hospital Clinico Universitario, Valencia, Spain.
authors.forename: Roberto
authors.initials: R
authors.lastname: Garcia-Civera
authors.forename: Ricardo
authors.initials: R
authors.lastname: Ruiz-Granell
authors.forename: Salvador
authors.initials: S
authors.lastname: Morell-Cabedo
authors.forename: Rafael
authors.initials: R
authors.lastname: Sanjuan-Mañez
authors.forename: Francisco
authors.initials: F
authors.lastname: Perez-Alcala
authors.forename: Eva
authors.initials: E
authors.lastname: Plancha
authors.forename: Alejandro
authors.initials: A
authors.lastname: Navarro
authors.forename: Segismundo
authors.initials: S
authors.lastname: Botella
authors.forename: Angel
authors.initials: A
authors.lastname: LLacer
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D003937:Diagnosis, Differential; D003955:Diagnostic Tests, Routine; D004562:Electrocardiography; D015716:Electrocardiography, Ambulatory / Q000379:methods; D004567:Electrodes, Implanted; D004594:Electrophysiology / Q000379:methods*; D005260:Female; D006331:Heart Diseases / Q000175:diagnosis*; D006801:Humans; D008297:Male; D008487:Medical History Taking; D008875:Middle Aged; D011336:Probability; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric; D013575:Syncope / Q000175:diagnosis* / Q000209:etiology; D019462:Syncope, Vasovagal / Q000175:diagnosis / Q000209:etiology; D018667:Tilt-Table Test