title: Assessing epicardial substrate using intracardiac echocardiography during VT ablation.
abstract: BACKGROUND
  Intracardiac echocardiography (ICE) has played a limited role in defining the substrate for ventricular tachycardia (VT). The purpose of this study was to assess whether ICE could identify abnormal epicardial substrate in patients with nonischemic cardiomyopathy (NICM) and VT.
  
  
  RESULTS
  We studied 18 patients with NICM and recurrent VT who had abnormal echogenicity identified on ICE imaging. Detailed left ventricular (LV) endocardial and epicardial electroanatomic mapping was performed in all patients. Low-voltage areas (<1.0 mV) in the epicardium were analyzed. ICE imaging in the NICM group was compared to a control group of 30 patients with structurally normal hearts who underwent ICE imaging for other ablation procedures. In 18 patients (age, 53±13 years; 17 men) with NICM (ejection fraction, 37±13%), increased echogenicity was identified in the lateral LV by ICE imaging. LV endocardial electroanatomic mapping identified normal voltage in 9 patients and at least 1 confluent low-voltage area (6.6 cm(2); minimum-maximum, 2.1-31.7 cm(2)) in 9 patients (5 posterolateral LV, 4 perivalvular LV). Detailed epicardial mapping revealed areas of low voltage (39 cm(2); minimum-maximum, 18.5-96.3 cm(2)) and abnormal, fractionated electrograms in all 18 patients (15 posterolateral LV, 3 lateral LV). In all patients, the epicardial scar identified by electroanatomic mapping correlated with the echogenic area identified on ICE imaging. ICE imaging identified no areas of increased echogenicity in the control group.
  
  
  CONCLUSIONS
  ICE imaging identified increased echogenicity in the lateral wall of the LV that correlated to abnormal epicardial substrate. These findings suggest that ICE imaging may be useful to identify epicardial substrate in NICM.
authors: Cardiovascular Division, Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA. balar@uphs.upenn.edu
authors: Rupa
authors: R
authors: Bala
authors: Jian-Fang
authors: JF
authors: Ren
authors: Mathew D
authors: MD
authors: Hutchinson
authors: Benoit
authors: B
authors: Desjardins
authors: Cory
authors: C
authors: Tschabrunn
authors: Edward P
authors: EP
authors: Gerstenfeld
authors: Rajat
authors: R
authors: Deo
authors: Sanjay
authors: S
authors: Dixit
authors: Fermin C
authors: FC
authors: Garcia
authors: Joshua
authors: J
authors: Cooper
authors: David
authors: D
authors: Lin
authors: Michael P
authors: MP
authors: Riley
authors: Wendy S
authors: WS
authors: Tzou
authors: Ralph
authors: R
authors: Verdino
authors: Andrew E
authors: AE
authors: Epstein
authors: David J
authors: DJ
authors: Callans
authors: Francis E
authors: FE
authors: Marchlinski
mesh_terms: D000328:Adult; D000792:Angiography; D057791:Cardiac Imaging Techniques / Q000379:methods*; D009202:Cardiomyopathies / Q000000981:diagnostic imaging / Q000473:pathology; D017115:Catheter Ablation; D004452:Echocardiography / Q000379:methods*; D022062:Electrophysiologic Techniques, Cardiac; D056149:Epicardial Mapping; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010496:Pericardium / Q000000981:diagnostic imaging* / Q000473:pathology; D017180:Tachycardia, Ventricular / Q000000981:diagnostic imaging / Q000601:surgery*