title: Imaging and epicardial substrate ablation of ventricular tachycardia in patients late after myocarditis.
abstract: OBJECTIVE
  We present clinical, electroanatomical mapping (EAM), imaging, and catheter ablation (CA) strategies in patients with myocarditis-related ventricular tachycardia (VT).
  
  
  RESULTS
  Between January 2010 and July 2012, 26 consecutive patients underwent imaging-guided CA of myocarditis-related ventricular arrhythmias, 23 of 26 using a combined endo-epicardial approach. Segment per segment correspondence of late enhanced (LE) scar localization with EAM scar was assessed in all patients with available uni/bipolar maps (n = 19). Induced VTs were targeted prior to substrate modification. Late potentials (LPs) abolition constituted a procedural endpoint independently from VT inducibility. Clinical monomorphic VT was induced in 15 of 26 patients (57.7%) and was associated with epicardial LPs in 10 of 15, completely abolished in 7 of 10 patients. Of the 10 patients rendered non-inducible VTs were ablated epicardially in 7. Late potentials were also detected in 7 of 11 initially non-inducible patients and completely abolished in 4. After a median follow-up of 23 (15-31) months, 20 of 26 patients (76.9%) remained free from VT recurrence. Bipolar mapping revealed low-voltage scar (<1.5 mV) in 1 patient endocardially and in 14 of 19 epicardially. Unipolar mapping revealed low-voltage scar (<8 mV) in 12 of 19 patients endocardially and in 18 of 19 epicardially. Correspondence of LE scar localization with endocardial bipolar scar was 1%, with endocardial unipolar scar 23.7%, with epicardial bipolar scar 39.8%, and with epicardial unipolar scar 66.2%.
  
  
  CONCLUSIONS
  Pre-procedural scar imaging and EAM findings support the necessity of an epicardial approach in patients with prior myocarditis. Epicardial unipolar mapping (<8 mV) is superior in scar identification and CA based on substrate modification is safe and effective in this setting.
authors.affiliation: Arrhythmia Unit and Electrophysiology Laboratories, San Raffaele University Hospital, Milan, Italy maccabelli.giuseppe@hsr.it.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Maccabelli
authors.affiliation: Arrhythmia Unit and Electrophysiology Laboratories, San Raffaele University Hospital, Milan, Italy.
authors.forename: Dimitris
authors.initials: D
authors.lastname: Tsiachris
authors.affiliation: Arrhythmia Unit and Electrophysiology Laboratories, San Raffaele University Hospital, Milan, Italy.
authors.forename: John
authors.initials: J
authors.lastname: Silberbauer
authors.affiliation: Department of Radiology, San Raffaele University Hospital, Milan, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Esposito
authors.affiliation: Arrhythmia Unit and Electrophysiology Laboratories, San Raffaele University Hospital, Milan, Italy.
authors.forename: Caterina
authors.initials: C
authors.lastname: Bisceglia
authors.affiliation: Arrhythmia Unit and Electrophysiology Laboratories, San Raffaele University Hospital, Milan, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Baratto
authors.affiliation: Department of Radiology, San Raffaele University Hospital, Milan, Italy.
authors.forename: Caterina
authors.initials: C
authors.lastname: Colantoni
authors.affiliation: Arrhythmia Unit and Electrophysiology Laboratories, San Raffaele University Hospital, Milan, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Trevisi
authors.affiliation: Department of Radiology, San Raffaele University Hospital, Milan, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Palmisano
authors.affiliation: Arrhythmia Unit and Electrophysiology Laboratories, San Raffaele University Hospital, Milan, Italy.
authors.forename: Pasquale
authors.initials: P
authors.lastname: Vergara
authors.affiliation: Department of Radiology, San Raffaele University Hospital, Milan, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: De Cobelli
authors.affiliation: Department of Radiology, San Raffaele University Hospital, Milan, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Del Maschio
authors.affiliation: Arrhythmia Unit and Electrophysiology Laboratories, San Raffaele University Hospital, Milan, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Della Bella
mesh_terms: D000328:Adult; D000368:Aged; D018780:Body Surface Potential Mapping / Q000379:methods*; D017115:Catheter Ablation / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009205:Myocarditis / Q000150:complications* / Q000175:diagnosis / Q000601:surgery*; D010496:Pericardium / Q000601:surgery*; D025321:Surgery, Computer-Assisted / Q000379:methods; D017180:Tachycardia, Ventricular / Q000175:diagnosis / Q000209:etiology* / Q000601:surgery*; D016896:Treatment Outcome; D055815:Young Adult
keywords: Catheter ablation; Electroanatomical mapping; Late enhancement imaging; Myocarditis; Ventricular tachycardia