title: Performance of the SA-VA Difference to Differentiate Atrioventricular Nodal Reentrant Tachycardia from Orthodromic Reentrant Tachycardia in a Large Cohort of Consecutive Patients.
abstract: BACKGROUND
  The stimulus-atrial (SA) interval minus ventriculoatrial (VA) interval (SA-VA) difference represents a simple diagnostic maneuver to distinguish between atrioventricular nodal reentrant tachycardia (AVNRT) and orthodromic reentrant tachycardia (ORT) during electrophysiology study. However, its usefulness has largely been studied in selected patient subgroups. The purpose of this study was to evaluate the performance of the SA-VA difference against commonly used diagnostic maneuvers in a large cohort of consecutive patients.
  
  
  METHODS
  Consecutive patients with inducible supraventricular tachycardia and successful entrainment through pacing trains from right ventricular apex during an electrophysiological study were included. Atrial tachycardias were excluded. The following intervals were calculated for each patient: SA-VA difference, His potential, and atrial electrogram during entrainment minus His potential and atrial electrogram during tachycardia, and the corrected return cycle.
  
  
  RESULTS
  A total of 456 patients fulfilled the inclusion criteria, of which electrophysiological study revealed 265 typical AVNRT, 38 atypical AVNRT, and 54 and 108 ORT through a septal and free-wall accessory pathway, respectively. An SA-VA difference >99 ms identified AVNRT in all patients with sensitivity, specificity, and positive and negative predictive values of 97.7%, 96.9%, 98.3%, and 95.7%, respectively.
  
  
  CONCLUSIONS
  This study confirms the high ability to distinguish AVNRT from ORT using the SA-VA difference, not only in selected patient subgroups, but as whole when a cut-off of >99 ms is used.
authors.affiliation: Cardiac Arrhythmia and Electrophysiology Unit, Department of Cardiology, Hospital Virgen de la Salud, Toledo, Spain.
authors.forename: Finn
authors.initials: F
authors.lastname: Akerström
authors.affiliation: Cardiac Arrhythmia and Electrophysiology Unit, Department of Cardiology, Hospital Virgen de la Salud, Toledo, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Pachón
authors.affiliation: Arrhythmia Unit, Cardiology Department, Complejo Asistencial Universitario de Burgos, Burgos, Spain.
authors.forename: Francisco Javier
authors.initials: FJ
authors.lastname: García-Fernández
authors.affiliation: Cardiac Arrhythmia and Electrophysiology Unit, Department of Cardiology, Hospital Virgen de la Salud, Toledo, Spain.
authors.forename: Alberto
authors.initials: A
authors.lastname: Puchol
authors.affiliation: Arrhythmia Unit, Cardiology Department, Complejo Asistencial Universitario de Burgos, Burgos, Spain.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Salgado
authors.affiliation: Cardiac Arrhythmia and Electrophysiology Unit, Department of Cardiology, Hospital Virgen de la Salud, Toledo, Spain.
authors.forename: Luis
authors.initials: L
authors.lastname: Rodríguez-Padial
authors.affiliation: Cardiac Arrhythmia and Electrophysiology Unit, Department of Cardiology, Hospital Virgen de la Salud, Toledo, Spain.
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Arias
mesh_terms: D058606:Accessory Atrioventricular Bundle / Q000175:diagnosis*; D000328:Adult; D015331:Cohort Studies; D022062:Electrophysiologic Techniques, Cardiac / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000175:diagnosis*; D054139:Tachycardia, Reciprocating / Q000175:diagnosis*
keywords: accessory pathway; atrioventricular nodal reentry; entrainment; orthodromic reentrant tachycardia; pacing maneuver; supraventricular tachycardia