title: Three-dimensional electroanatomical voltage mapping and histologic evaluation of myocardial substrate in right ventricular outflow tract tachycardia.
abstract: OBJECTIVE
  We tested whether 3-dimensional electroanatomical voltage mapping (EVM) may help in the differential diagnosis between idiopathic right ventricular outflow tract (RVOT) tachycardia and arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D).
  
  
  BACKGROUND
  Right ventricular EVM has been demonstrated to reliably identify low-voltage regions ("electroanatomical scar"), which in patients with ARVC/D correspond to areas of fibrofatty myocardial replacement.
  
  
  METHODS
  The study population comprised 27 patients (15 men and 12 women, age 33.9 +/- 8 years) with RVOT tachycardia and no echocardiographic/angiographic evidence of right ventricular (RV) dilation/dysfunction, who underwent EVM and endomyocardial biopsy (EMB) for characterization of ventricular tachycardia (VT) substrate before catheter ablation.
  
  
  RESULTS
  Electroanatomical voltage mapping was normal in 20 of 27 patients (74%, group A), with electrogram voltage >1.5 mV throughout the RV. The other 7 patients (26%, group B) showed >/=1 (1.4 +/- 07) RV electroanatomical scar area(s) (bipolar voltage <0.5 mV) that correlated with fibrofatty myocardial replacement at EMB (p < 0.001). Clinical predictors of RV scar were right precordial QRS prolongation (p < 0.001) and VT inducibility (p = 0.001). Catheter ablation successfully eliminated VT in 18 of 20 patients (90%). During a follow-up of 41 +/- 8 months, 3 of 7 patients (43%) from group B received an implantable defibrillator because of life-threatening ventricular arrhythmias, compared with no patients from group A (p = 0.016).
  
  
  CONCLUSIONS
  An early/minor form of ARVC/D may mimic idiopathic RVOT tachycardia. Electroanatomical voltage mapping is able to identify RVOT tachycardia due to concealed ARVC/D by detecting RVOT electroanatomical scars that correlate with fibrofatty myocardial replacement at EMB and predispose to sudden arrhythmic death.
authors.affiliation: Department of Cardiac, Thoracic, and Vascular Sciences, University of Padua Medical School, Padua, Italy. domenico.corrado@unipd.it
authors.forename: Domenico
authors.initials: D
authors.lastname: Corrado
authors.forename: Cristina
authors.initials: C
authors.lastname: Basso
authors.forename: Loira
authors.initials: L
authors.lastname: Leoni
authors.forename: Barbara
authors.initials: B
authors.lastname: Tokajuk
authors.forename: Pietro
authors.initials: P
authors.lastname: Turrini
authors.forename: Barbara
authors.initials: B
authors.lastname: Bauce
authors.forename: Federico
authors.initials: F
authors.lastname: Migliore
authors.forename: Andrea
authors.initials: A
authors.lastname: Pavei
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Tarantini
authors.forename: Massimo
authors.initials: M
authors.lastname: Napodano
authors.forename: Angelo
authors.initials: A
authors.lastname: Ramondo
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Buja
authors.forename: Sabino
authors.initials: S
authors.lastname: Iliceto
authors.forename: Gaetano
authors.initials: G
authors.lastname: Thiene
mesh_terms: D000328:Adult; D019571:Arrhythmogenic Right Ventricular Dysplasia / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery; D017115:Catheter Ablation; D003937:Diagnosis, Differential; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac / Q000379:methods; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000473:pathology*; D012680:Sensitivity and Specificity; D017180:Tachycardia, Ventricular / Q000209:etiology / Q000473:pathology* / Q000503:physiopathology; D016278:Ventricular Function, Right