title: Characterization of the arrhythmogenic substrate in patients with arrhythmogenic right ventricular cardiomyopathy undergoing ventricular tachycardia ablation.
abstract: OBJECTIVE
  Arrhythmogenic right ventricular (RV) cardiomyopathy (ARVC) is associated with ventricular arrhythmias, even without RV structural disease. We aimed to characterize the RV substrate using electroanatomical mapping and to define outcomes following ventricular tachycardia (VT) ablation in patients with and without RV structural abnormalities.
  
  
  RESULTS
  Twenty-nine patients with definite or suspected ARVC undergoing VT ablation were classified as 'electrical' and 'structural' cardiomyopathy based on the absence or presence of major structural criteria. Right ventricular (RV) endocardial and epicardial mapping with assessment of bipolar and unipolar voltages, distribution of late potentials (LPs), and inducible VT morphologies were performed. The endpoints for VT ablation were VT non-inducibility and LP abolition. Fourteen patients were categorized as electrical RV cardiomyopathy and 15 were categorized as structural RV cardiomyopathy. In patients with electrical cardiomyopathy, scar was limited to the epicardial surface (epicardium 13 cm2vs. endocardium 1 cm2, P < 0.05), primarily in the outflow tract, whereas patients with structural disease had greater involvement of the endocardium. During a mean follow-up of 22 ± 11 months, the VT recurrence rate was 27%, with LP abolition being a predictor of VT-free survival (HR 0.075 (0.008-0.661), P = 0.020). There was a trend towards higher recurrence rates in structural RV cardiomyopathy (40%) compared with the electrical cardiomyopathy (15%, P = 0.17).
  
  
  CONCLUSIONS
  The development of RV structural disease in patients with ARVC is associated with extensive epicardial and endocardial scar. Conversely those patients without RV structural disease have identifiable epicardial scar limited to the RV outflow tract. Ventricular tachycardia (VT) ablation in both groups targeting LP abolition is effective in preventing VT recurrence.
authors.forename: Senthil
authors.initials: S
authors.lastname: Kirubakaran
authors.forename: Caterina
authors.initials: C
authors.lastname: Bisceglia
authors.forename: John
authors.initials: J
authors.lastname: Silberbauer
authors.forename: Teresa
authors.initials: T
authors.lastname: Oloriz
authors.forename: Giulia
authors.initials: G
authors.lastname: Santagostino
authors.forename: Miki
authors.initials: M
authors.lastname: Yamase
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Maccabelli
authors.forename: Nicola
authors.initials: N
authors.lastname: Trevisi
authors.forename: Paolo
authors.initials: P
authors.lastname: Della Bella
mesh_terms: D000200:Action Potentials; D000328:Adult; D019571:Arrhythmogenic Right Ventricular Dysplasia / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology; D017115:Catheter Ablation / Q000009:adverse effects; D018572:Disease-Free Survival; D056149:Epicardial Mapping; D005260:Female; D006339:Heart Rate; D006352:Heart Ventricles / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D012008:Recurrence; D012189:Retrospective Studies; D012307:Risk Factors; D017180:Tachycardia, Ventricular / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology / Q000601:surgery*; D013997:Time Factors; D016896:Treatment Outcome; D016278:Ventricular Function, Right; D020257:Ventricular Remodeling
keywords: Ablation; Cardiomyopathy; Ventricular tachycardia