title: Missing diagnosis of preexcitation syndrome on ECG: clinical and electrophysiological significance.
abstract: Electrocardiographic criteria of preexcitation syndrome are sometimes not visible on ECG in sinus rhythm (SR). The purpose of the study was to evaluate the significance of unapparent preexcitation syndrome in SR, when overt conduction through accessory pathway (AP) was noted at atrial pacing.
  
  
  METHODS
  Anterograde conduction through atrioventricular AP was identified at electrophysiological study (EPS) in 712 patients, studied for tachycardia (n=316), syncope (n=89) or life-threatening arrhythmia (n=55) or asymptomatic preexcitation syndrome (n=252). ECG in SR at the time of EPS was analysed.
  
  
  RESULTS
  78 patients (11%) (group I) had a normal ECG in SR and anterograde conduction over AP at atrial pacing; 634 (group II) had overt preexcitation in SR. Group I was as frequently asymptomatic (35%) as group II (35%), had as frequently tachycardias, syncope or life-threatening arrhythmia as group II (43, 5, 2% vs 43, 13, 8%). AP was more frequently left lateral in group I (57%) than in group II (36%)(p<0.001). AV re-entrant tachycardia, atrial fibrillation (AF), antidromic tachycardia were induced as frequently in group I (54, 18, 10%) as in group II (54, 27, 7%). Malignant forms (induced AF with RR intervals between preexcited beats <250ms in control state or <200ms after isoproterenol) were as frequent in group I (11.5%) as II (14%).
  
  
  CONCLUSIONS
  The frequency of unapparent preexcitation syndrome represents 11% of our population with anterograde conduction through an AP and could be underestimated. The risk to have a malignant form is as high as in patients with overt preexcitation syndrome in SR.
authors.affiliation: Department of cardiology, University Hospital of Brabois, Vandoeuvre, France. Electronic address: b.brembilla-perrot@chu-nancy.fr.
authors.forename: Béatrice
authors.initials: B
authors.lastname: Brembilla-Perrot
authors.affiliation: Department of cardiology, University Hospital of Brabois, Vandoeuvre, France.
authors.forename: Rouzbeh Valizadeh
authors.initials: RV
authors.lastname: Moejezi
authors.affiliation: Department of cardiology, University Hospital of Brabois, Vandoeuvre, France.
authors.forename: Pierre Yves
authors.initials: PY
authors.lastname: Zinzius
authors.affiliation: Department of cardiology, University Hospital of Brabois, Vandoeuvre, France.
authors.forename: Soumaya
authors.initials: S
authors.lastname: Jarmouni
authors.affiliation: Department of cardiology, University Hospital of Brabois, Vandoeuvre, France.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Schwartz
authors.affiliation: Department of cardiology, University Hospital of Brabois, Vandoeuvre, France.
authors.forename: Daniel
authors.initials: D
authors.lastname: Beurrier
authors.affiliation: Department of cardiology, University Hospital of Brabois, Vandoeuvre, France.
authors.forename: Jean Marc
authors.initials: JM
authors.lastname: Sellal
authors.affiliation: Department of cardiology, University Hospital of Brabois, Vandoeuvre, France.
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Nossier
authors.affiliation: Department of cardiology, University Hospital of Brabois, Vandoeuvre, France.
authors.forename: Lucian
authors.initials: L
authors.lastname: Muresan
authors.affiliation: Department of cardiology, University Hospital of Brabois, Vandoeuvre, France.
authors.forename: Marius
authors.initials: M
authors.lastname: Andronache
authors.affiliation: Department of cardiology, University Hospital of Brabois, Vandoeuvre, France.
authors.forename: Radou
authors.initials: R
authors.lastname: Moisei
authors.affiliation: Department of cardiology, University Hospital of Brabois, Vandoeuvre, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Selton
authors.affiliation: Department of cardiology, University Hospital of Brabois, Vandoeuvre, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Louis
authors.affiliation: Department of cardiology, University Hospital of Brabois, Vandoeuvre, France.
authors.forename: Arnaud Terrier
authors.initials: AT
authors.lastname: de la Chaise
mesh_terms: D000293:Adolescent; D000328:Adult; D003951:Diagnostic Errors / Q000517:prevention & control; D004562:Electrocardiography / Q000379:methods* / Q000592:standards; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011226:Pre-Excitation Syndromes / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology*; D012189:Retrospective Studies; D055815:Young Adult