title: Cardiac magnetic resonance imaging and electroanatomic voltage discordance in non-ischemic left ventricle ventricular tachycardia and premature ventricular depolarizations.
abstract: OBJECTIVE
  Magnetic resonance imaging (MRI) with late gadolinium enhancement is commonly performed in patients with non-ischemic LV ventricular tachycardia/ventricular premature depolarizations (non-ischemic LV-VT/VPDs) to define VT substrate prior to catheter ablation. We investigated the prevalence of abnormal voltage and VT localized to areas of the myocardium not reported to have late gadolinium enhancement (LGE) on routine pre-procedural MRI and sought to determine if quantitative MRI analysis could reduce this discordance.
  
  
  METHODS
  Patients with non-ischemic LV-VT/VPD who underwent LV endocardial mapping with VT/VPD ablation and either septal or free wall MRI-voltage discordance were studied. Electroanatomic maps were analyzed post-procedure for areas of electrogram-defined scar and VT localized to areas without reported LGE. Discordant segments were then analyzed offline using delayed signal intensity of >2 and >5 standard deviations above normal myocardium.
  
  
  RESULTS
  Of 90 consecutive patients, 32 (36%) patients with septal (n = 16), free wall (n = 14) or both (n = 2) MRI-voltage + mismatch were identified. All discordant segments demonstrated unipolar voltage abnormalities with 12 patients (6 septal and 6 free wall) also showing low bipolar voltage but no LGE at signal intensity >5 standard deviations. Eleven patients (5 septum, 6 free wall) had VT localized to discordant areas. Ninety-three percent of patients in the septal group (26/48 segments) and 89% of patients in the free wall group (9/13 segments) had a concordant response established by using a signal intensity cutoff of >2 standard deviations.
  
  
  CONCLUSIONS
  MRI-voltage discordance was identified in 36% of patients with non-ischemic LV-VT/VPD who underwent VT ablation. In 12% of patients, VT was targeted in areas of abnormal voltage not suggested by routine qualitative MRI. Quantitative MRI analysis using a lower signal intensity threshold increased the sensitivity for detecting areas of clinically relevant VT substrate.
authors.affiliation: Cardiac Electrophysiology Section, Hospital of the University of Pennsylvania, 3400 Spruce Street, Founders 9, Philadelphia, PA, 19104, USA.
authors.forename: Brian P
authors.initials: BP
authors.lastname: Betensky
authors.affiliation: Cardiovascular Division, Hospital of the University of Pennsylvania, Philadelphia, PA, USA.|Department of Cardiology, PLA General Hospital, Beijing, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Dong
authors.affiliation: Cardiac Electrophysiology Section, Hospital of the University of Pennsylvania, 3400 Spruce Street, Founders 9, Philadelphia, PA, 19104, USA.
authors.forename: Benjamin A
authors.initials: BA
authors.lastname: D'Souza
authors.affiliation: Cardiac Electrophysiology Section, Hospital of the University of Pennsylvania, 3400 Spruce Street, Founders 9, Philadelphia, PA, 19104, USA.
authors.forename: Erica S
authors.initials: ES
authors.lastname: Zado
authors.affiliation: Cardiovascular Division, Hospital of the University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: Yuchi
authors.initials: Y
authors.lastname: Han
authors.affiliation: Cardiac Electrophysiology Section, Hospital of the University of Pennsylvania, 3400 Spruce Street, Founders 9, Philadelphia, PA, 19104, USA. francis.marchlinski@uphs.upenn.edu.
authors.forename: Francis E
authors.initials: FE
authors.lastname: Marchlinski
mesh_terms: D018780:Body Surface Potential Mapping / Q000379:methods*; D057791:Cardiac Imaging Techniques / Q000379:methods*; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging*; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017180:Tachycardia, Ventricular / Q000175:diagnosis*; D018879:Ventricular Premature Complexes / Q000175:diagnosis*
keywords: Ablation; Late gadolinium enhancement; MRI; Non-ischemic LV ventricular tachycardia/ventricular premature depolarizations; Ventricular tachycardia