title: Postmyocarditis ventricular tachycardia in patients with epicardial-only scar: a specific entity requiring a specific approach.
abstract: BACKGROUND
  Nonischemic cardiomyopathy is a heterogeneous condition providing a favorable substrate for ventricular tachycardia (VT).
  
  
  OBJECTIVE
  The purpose of this study is to further characterize the substrate in a subset of postmyocarditis patients with epicardial-only scar.
  
  
  METHODS
  Twelve postmyocarditis patients (11 male, 49 ± 14 years, left ventricular ejection fraction 49 ± 12%) with VT and epicardial-only scar were included for analysis comparing automatic high-amplitude normal activity (HANA) maps to manually adjusted maps of based on local abnormal ventricular activity (LAVA) electrograms when present. A combined endocardial (endo) and epicardial (epi) approach was used in 11/12 with usual bipolar/unipolar voltage thresholds and analyzed using image integration.
  
  
  RESULTS
  A delayed enhancement MRI scar area of 52 cm(2) (38, 59) and multidetector CT wall thinning area of 18 cm(2) (14, 35) was found. Bipolar voltage substrate mapping (160 points [101, 239] endo, 553 points [232, 713] epi and LAVA were found only epicardially [443 LAVA points] in all) illustrated a low-voltage area of HANA: 1 cm(2) (0, 10) endo, 25 cm(2) (22, 39) epi and LAVA: 1 cm(2) (0, 10) endo, 39 cm(2) (28, 51) epi. Manual maps performed better than automatic maps for delineating low-voltage area with a higher overlap with scar area on delayed enhancement magnetic resonance imaging (DE-MRI; 76% [66, 94] vs. 45% [35, 62]; P = 0.04). In addition, manual voltage maps also showed a higher overlap with location of LAVA (LAVA in normal voltage area: 3% [0, 9] vs. 35% [32, 41]; P < 0.05).
  
  
  CONCLUSIONS
  In postmyocarditis patients with epicardial-only scar, automatic voltage mapping may miss or minimize the electrical VT substrate. DE-MRI and manual LAVA-based voltage mapping are necessary to optimize scar delineation. Epicardial access is critical for mapping and ablation in this condition.
authors.affiliation: Hôpital Cardiologique du Haut-L'évêque, Université de Bordeaux, LIRYC Institut:, IHU LIRYC ANR-10-IAHU-04 et Equipex MUSIC ANR-11-EQPX-0030, Bordeaux, France.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Berte
authors.forename: Frederic
authors.initials: F
authors.lastname: Sacher
authors.forename: Hubert
authors.initials: H
authors.lastname: Cochet
authors.forename: Saagar
authors.initials: S
authors.lastname: Mahida
authors.forename: Seigo
authors.initials: S
authors.lastname: Yamashita
authors.forename: Han
authors.initials: H
authors.lastname: Lim
authors.forename: Arnaud
authors.initials: A
authors.lastname: Denis
authors.forename: Nicolas
authors.initials: N
authors.lastname: Derval
authors.forename: Mélèze
authors.initials: M
authors.lastname: Hocini
authors.forename: Michel
authors.initials: M
authors.lastname: Haïssaguerre
authors.forename: Pierre
authors.initials: P
authors.lastname: Jaïs
mesh_terms: D000200:Action Potentials; D000328:Adult; D000368:Aged; D017115:Catheter Ablation / Q000379:methods; D002921:Cicatrix / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D005602:France; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography; D009205:Myocarditis / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology; D010496:Pericardium / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012307:Risk Factors; D013318:Stroke Volume; D017180:Tachycardia, Ventricular / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology / Q000601:surgery; D016277:Ventricular Function, Left
keywords: LAVA; VT ablation; cardiac DE-MRI; epicardial scar; myocarditis