title: MRI-Guided ventricular tachycardia ablation: integration of late gadolinium-enhanced 3D scar in patients with implantable cardioverter-defibrillators.
abstract: BACKGROUND
  Substrate-guided ablation of ventricular tachycardia (VT) in patients with implanted cardioverter-defibrillators (ICDs) relies on voltage mapping to define the scar and border zone. An integrated 3D scar reconstruction from late gadolinium enhancement (LGE) MRI could facilitate VT ablations.
  
  
  RESULTS
  Twenty-two patients with ICD underwent contrast-enhanced cardiac MRI with a specific absorption rate of <2.0 W/kg before VT ablation. Device interrogation demonstrated unchanged ICD parameters immediately before, after, or at 68±21 days follow-up (P>0.05). ICD imaging artifacts were most prominent in the anterior wall and allowed full and partial assessment of LGE in 9±4 and 12±3 of 17 segments, respectively. In 14 patients with LGE, a 3D scar model was reconstructed and successfully registered with the clinical mapping system (accuracy, 3.9±1.8 mm). Using receiver operating characteristic curves, bipolar and unipolar voltages of 1.49 and 4.46 mV correlated best with endocardial MRI scar. Scar visualization allowed the elimination of falsely low voltage recordings (suboptimal catheter contact) in 4.1±1.9% of <1.5-mV mapping points. Display of scar border zone allowed identification of excellent pace mapping sites, with only limited voltage mapping in 64% of patients. Viable endocardium of >2 mm resulted in >1.5-mV voltage recordings despite up to 63% transmural midmyocardial scar successfully ablated with MRI guidance. All successful ablation sites demonstrated LGE (transmurality, 68±26%) and were located within 10 mm of transition zones to 0% to 25% scar in 71%.
  
  
  CONCLUSIONS
  Contrast-enhanced cardiac MRI can be safely performed in selected patients with ICDs and allows the integration of detailed 3D scar maps into clinical mapping systems, providing supplementary anatomic guidance to facilitate substrate-guided VT ablations.
authors.affiliation: Division of Cardiology, University of Maryland, Baltimore, 21201, USA. tdickfel@medicine.umaryland.edu
authors.forename: Timm
authors.initials: T
authors.lastname: Dickfeld
authors.forename: Jing
authors.initials: J
authors.lastname: Tian
authors.forename: Ghada
authors.initials: G
authors.lastname: Ahmad
authors.forename: Alejandro
authors.initials: A
authors.lastname: Jimenez
authors.forename: Aharon
authors.initials: A
authors.lastname: Turgeman
authors.forename: Richard
authors.initials: R
authors.lastname: Kuk
authors.forename: Matthew
authors.initials: M
authors.lastname: Peters
authors.forename: Anastasios
authors.initials: A
authors.lastname: Saliaris
authors.forename: Magdi
authors.initials: M
authors.lastname: Saba
authors.forename: Stephen
authors.initials: S
authors.lastname: Shorofsky
authors.forename: Jean
authors.initials: J
authors.lastname: Jeudy
mesh_terms: D000328:Adult; D000368:Aged; D016477:Artifacts; D017115:Catheter Ablation / Q000379:methods*; D002921:Cicatrix / Q000473:pathology; D003287:Contrast Media; D017147:Defibrillators, Implantable; D004554:Electric Countershock / Q000295:instrumentation*; D022062:Electrophysiologic Techniques, Cardiac; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D021621:Imaging, Three-Dimensional; D053783:Magnetic Resonance Imaging, Interventional; D008297:Male; D008536:Meglumine / Q000031:analogs & derivatives*; D008875:Middle Aged; D009942:Organometallic Compounds; D011237:Predictive Value of Tests; D025321:Surgery, Computer-Assisted / Q000379:methods*; D017180:Tachycardia, Ventricular / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C064572:gadobenic acid; D008536:Meglumine