title: 50 is the new 70: Short ventriculoatrial times are common in children with atrioventricular reciprocating tachycardia.
abstract: BACKGROUND
  One of the basic electrophysiological principles of atrioventricular reciprocating tachycardia (AVRT) is that ventriculoatrial (VA) times during tachycardia are >70 ms. We hypothesized, however, that children may commonly have VA times <70 ms in AVRT.
  
  
  OBJECTIVE
  This study sought to determine the incidence and characteristics associated with short-VA AVRT in children.
  
  
  METHODS
  A retrospective single-center review of children with AVRT from 2000 to 2014 was performed. All patients ≤18 years of age with AVRT at electrophysiology study were included. Patients with persistent junctional reciprocating tachycardia, atrioventricular nodal reentry tachycardia, and tachycardia not unequivocally proven to be AVRT were excluded. VA time was defined as the time between earliest ventricular activation and earliest atrial activation in any lead and was confirmed by 2 electrophysiologists. Patients with VA times <70 ms (SHORT-VA) and those with standard VA times ≥70 ms (STD-VA) were compared. Logistic regression analysis identified characteristics of SHORT-VA patients.
  
  
  RESULTS
  A total of 495 patients with AVRT were included (mean age 11.7 ± 4.1 years). There were 265 patients (54%) with concealed accessory pathways (APs) and 230 (46%) with Wolff-Parkinson-White syndrome. AP location was left-sided in 301 patients (61%) and right-sided in 194 (39%). The mean VA time in AVRT was 100 ± 33 ms. A total of 63 patients (13%) had VA times <70 ms (SHORT-VA). The shortest VA time during AVRT was 50 ms. There was no difference in age, AV nodal block cycle, or body surface area between SHORT-VA and STD-VA patients, but SHORT-VA patients had lower weight (43 ± 17 vs 51 ± 23 kg, P = .02), lower AV nodal effective refractory period (AVNERP; 269 ± 50 vs 245 ± 52 ms, P < .01), and more left-sided APs (50 [79%] vs 251 [58%]; P < .01]. On multivariate logistic regression, factors associated with SHORT-VA included left-sided AP (odds ratio [OR] 5.79, confidence interval [95% CI] 2.21-15.1, P < .01), shorter AVNERP (OR 0.99, CI 0.98-0.99, P < .01), and lower weight (OR 0.97, CI 0.95-0.99, P < .01).
  
  
  CONCLUSIONS
  Children with AVRT can frequently have VA times <70 ms, with 50 ms being the shortest VA time. This finding debunks the classic electrophysiology principle that VA times in AVRT must be >70 ms. SHORT-VA AVRT was more common in children with left-sided APs.
authors.affiliation: Lucile Packard Children's Hospital-Stanford University, Pediatric Cardiology, Pediatric Electrophysiology-Department of Pediatrics, Palo Alto, California. Electronic address: ceresnak@yahoo.com.
authors.forename: Scott R
authors.initials: SR
authors.lastname: Ceresnak
authors.affiliation: Lucile Packard Children's Hospital-Stanford University, Pediatric Cardiology, Pediatric Electrophysiology-Department of Pediatrics, Palo Alto, California; Lucille Packard Children's Hospital-Stanford University, Stanford Center for Clinical & Translational Research & Education and Stanford Child Health Research Institute Spectrum Child Health, Division of Pediatric Cardiology, Palo Alto, California.
authors.forename: Lan N
authors.initials: LN
authors.lastname: Doan
authors.affiliation: Lucile Packard Children's Hospital-Stanford University, Pediatric Cardiology, Pediatric Electrophysiology-Department of Pediatrics, Palo Alto, California.
authors.forename: Kara S
authors.initials: KS
authors.lastname: Motonaga
authors.affiliation: Lucile Packard Children's Hospital-Stanford University, Pediatric Cardiology, Pediatric Electrophysiology-Department of Pediatrics, Palo Alto, California.
authors.forename: Kishor
authors.initials: K
authors.lastname: Avasarala
authors.affiliation: Lucile Packard Children's Hospital-Stanford University, Pediatric Cardiology, Pediatric Electrophysiology-Department of Pediatrics, Palo Alto, California.
authors.forename: Anthony V
authors.initials: AV
authors.lastname: Trela
authors.affiliation: Lucile Packard Children's Hospital-Stanford University, Pediatric Cardiology, Pediatric Electrophysiology-Department of Pediatrics, Palo Alto, California.
authors.forename: Charitha D
authors.initials: CD
authors.lastname: Reddy
authors.affiliation: Lucile Packard Children's Hospital-Stanford University, Pediatric Cardiology, Pediatric Electrophysiology-Department of Pediatrics, Palo Alto, California.
authors.forename: Anne M
authors.initials: AM
authors.lastname: Dubin
mesh_terms: D058606:Accessory Atrioventricular Bundle / Q000503:physiopathology; D000293:Adolescent; D002140:California; D002648:Child; D003937:Diagnosis, Differential; D004562:Electrocardiography / Q000379:methods; D022062:Electrophysiologic Techniques, Cardiac / Q000379:methods; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology; D006352:Heart Ventricles / Q000503:physiopathology*; D006801:Humans; D008297:Male; D012032:Refractory Period, Electrophysiological; D012189:Retrospective Studies; D054139:Tachycardia, Reciprocating / Q000175:diagnosis / Q000503:physiopathology; D013617:Tachycardia, Supraventricular / Q000175:diagnosis / Q000503:physiopathology; D013997:Time Factors
keywords: Ablation; Atrioventricular reciprocating tachycardia; Children; Electrophysiology study; Pediatrics; Supraventricular tachycardia; Ventriculoatrial times