title: Dynamic conduction and repolarisation changes in early arrhythmogenic right ventricular cardiomyopathy versus benign outflow tract ectopy demonstrated by high density mapping & paced surface ECG analysis.
abstract: OBJECTIVE
  The concealed phase of arrhythmogenic right ventricular cardiomyopathy (ARVC) may initially manifest electrophysiologically. No studies have examined dynamic conduction/repolarization kinetics to distinguish benign right ventricular outflow tract ectopy (RVOT ectopy) from ARVC's early phase. We investigated dynamic endocardial electrophysiological changes that differentiate early ARVC disease expression from RVOT ectopy.
  
  
  METHODS
  22 ARVC (12 definite based upon family history and mutation carrier status, 10 probable) patients without right ventricular structural anomalies underwent high-density non-contact mapping of the right ventricle. These were compared to data from 14 RVOT ectopy and 12 patients with supraventricular tachycardias and normal hearts. Endocardial & surface ECG conduction and repolarization parameters were assessed during a standard S1-S2 restitution protocol.
  
  
  RESULTS
  Definite ARVC without RV structural disease could not be clearly distinguished from RVOT ectopy during sinus rhythm or during steady state pacing. Delay in Activation Times at coupling intervals just above the ventricular effective refractory period (VERP) increased in definite ARVC (43 ± 20 ms) more than RVOT ectopy patients (36 ± 14 ms, p = 0.03) or Normals (25 ± 16 ms, p = 0.008) and a progressive separation of the repolarisation time curves between groups existed. Repolarization time increases in the RVOT were also greatest in ARVC (definite ARVC: 18 ± 20 ms; RVOT ectopy: 5 ± 14, Normal: 1 ± 18, p<0.05). Surface ECG correlates of these intracardiac measurements demonstrated an increase of greater than 48 ms in stimulus to surface ECG J-point pre-ERP versus steady state, with an 88% specificity and 68% sensitivity in distinguishing definite ARVC from the other groups. This technique could not distinguish patients with genetic predisposition to ARVC only (probable ARVC) from controls.
  
  
  CONCLUSIONS
  Significant changes in dynamic conduction and repolarization are apparent in early ARVC before detectable RV structural abnormalities, and were present to a lesser degree in probable ARVC patients. Investigation of dynamic electrophysiological parameters may be useful to identify concealed ARVC in patients without disease pedigrees by using endocardial electrogram or paced ECG parameters.
authors.affiliation: Institute of Cardiovascular Science, University College London, London, United Kingdom.
authors.forename: Malcolm C
authors.initials: MC
authors.lastname: Finlay
authors.affiliation: Institute of Cardiovascular Science, University College London, London, United Kingdom.
authors.forename: Akbar K
authors.initials: AK
authors.lastname: Ahmed
authors.affiliation: Institute of Cardiovascular Science, University College London, London, United Kingdom.
authors.forename: Alan
authors.initials: A
authors.lastname: Sugrue
authors.affiliation: Institute of Cardiovascular Science, University College London, London, United Kingdom.
authors.forename: Justine
authors.initials: J
authors.lastname: Bhar-Amato
authors.affiliation: Institute of Cardiovascular Science, University College London, London, United Kingdom.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Quarta
authors.affiliation: Institute of Cardiovascular Science, University College London, London, United Kingdom.
authors.forename: Antonis
authors.initials: A
authors.lastname: Pantazis
authors.affiliation: Department of Medicine, Columbia University, New York, New York, United States of America.
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Ciaccio
authors.affiliation: Institute of Cardiovascular Science, University College London, London, United Kingdom.
authors.forename: Petros
authors.initials: P
authors.lastname: Syrris
authors.affiliation: Institute of Cardiovascular Science, University College London, London, United Kingdom.
authors.forename: Srijita
authors.initials: S
authors.lastname: Sen-Chowdhry
authors.affiliation: Institute of Cardiovascular Science, University College London, London, United Kingdom.
authors.forename: Ron
authors.initials: R
authors.lastname: Ben-Simon
authors.affiliation: Institute of Cardiovascular Science, University College London, London, United Kingdom.
authors.forename: Anthony W
authors.initials: AW
authors.lastname: Chow
authors.affiliation: Institute of Cardiovascular Science, University College London, London, United Kingdom.
authors.forename: Martin D
authors.initials: MD
authors.lastname: Lowe
authors.affiliation: Institute of Cardiovascular Science, University College London, London, United Kingdom.
authors.forename: Oliver R
authors.initials: OR
authors.lastname: Segal
authors.affiliation: Institute of Cardiovascular Science, University College London, London, United Kingdom.
authors.forename: William J
authors.initials: WJ
authors.lastname: McKenna
authors.affiliation: Institute of Cardiovascular Science, University College London, London, United Kingdom.
authors.forename: Pier D
authors.initials: PD
authors.lastname: Lambiase
mesh_terms: D000328:Adult; D000368:Aged; D019571:Arrhythmogenic Right Ventricular Dysplasia / Q000175:diagnosis* / Q000503:physiopathology; D003937:Diagnosis, Differential; D004562:Electrocardiography; D004699:Endocardium / Q000503:physiopathology*; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006339:Heart Rate; D006352:Heart Ventricles / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017180:Tachycardia, Ventricular / Q000175:diagnosis / Q000503:physiopathology; D018879:Ventricular Premature Complexes / Q000175:diagnosis / Q000503:physiopathology