title: Correlation of scar in cardiac MRI and high-resolution contact mapping of left ventricle in a chronic infarct model.
abstract: BACKGROUND
  Endocardial mapping for scars and abnormal electrograms forms the most essential component of ventricular tachycardia ablation. The utility of ultra-high resolution mapping of ventricular scar was assessed using a multielectrode contact mapping system in a chronic canine infarct model.
  
  
  METHODS
  Chronic infarcts were created in five anesthetized dogs by ligating the left anterior descending coronary artery. Late gadolinium-enhanced magnetic resonance imaging (LGE MRI) was obtained 4.9 ± 0.9 months after infarction, with three-dimensional (3D) gadolinium enhancement signal intensity maps at 1-mm and 5-mm depths from the endocardium. Ultra-high resolution electroanatomical maps were created using a novel mapping system (Rhythmia Mapping System, Rhythmia Medical/Boston Scientific, Marlborough, MA, USA) Rhythmia Medical, Boston Scientific, Marlborough, MA, USA with an 8.5F catheter with mini-basket electrode array (64 tiny electrodes, 2.5-mm spacing, center-to-center).
  
  
  RESULTS
  The maps contained 7,754 ± 1,960 electrograms per animal with a mean resolution of 2.8 ± 0.6 mm. Low bipolar voltage (<2 mV) correlated closely with scar on the LGE MRI and the 3D signal intensity map (1-mm depth). The scar areas between the MRI signal intensity map and electroanatomic map matched at 87.7% of sites. Bipolar and unipolar voltages, compared in 592 electrograms from four MRI-defined scar types (endocardial scar, epicardial scar, mottled transmural scar, and dense transmural scar) as well as normal tissue, were significantly different. A unipolar voltage of <13 mV correlated with transmural extension of scar in MRI. Electrograms exhibiting isolated late potentials (ILPs) were manually annotated and ILP maps were created showing ILP location and timing. ILPs were identified in 203 ± 159 electrograms per dog (within low-voltage areas) and ILP maps showed gradation in timing of ILPs at different locations in the scar.
  
  
  CONCLUSIONS
  Ultra-high resolution contact electroanatomical mapping accurately localizes ventricular scar and abnormal myocardial tissue in this chronic canine infarct model. The high fidelity electrograms provided clear identification of the very low amplitude ILPs within the scar tissue and has the potential to quickly identify targets for ablation.
authors: Heart Institute.
authors: Anees
authors: A
authors: Thajudeen
authors: Heart Rhythm Institute, University of Oklahoma, Oklahoma City, Oklahoma.
authors: Warren M
authors: WM
authors: Jackman
authors: Rhythmia Medical, Boston Scientific, Marlborough, Massachusetts.
authors: Brian
authors: B
authors: Stewart
authors: Biomedical Imaging Research Institute, Cedars Sinai Medical Center, Los Angeles, California.
authors: Ivan
authors: I
authors: Cokic
authors: Heart Rhythm Institute, University of Oklahoma, Oklahoma City, Oklahoma.
authors: Hiroshi
authors: H
authors: Nakagawa
authors: Heart Institute.
authors: Michael
authors: M
authors: Shehata
authors: Heart Institute.
authors: Allen M
authors: AM
authors: Amorn
authors: Biomedical Imaging Research Institute, Cedars Sinai Medical Center, Los Angeles, California.|Department of Bioengineering, University of California, Los Angeles, California.
authors: Avinash
authors: A
authors: Kali
authors: Heart Institute.
authors: Ezh
authors: E
authors: Liu
authors: Rhythmia Medical, Boston Scientific, Marlborough, Massachusetts.
authors: Doron
authors: D
authors: Harlev
authors: Rhythmia Medical, Boston Scientific, Marlborough, Massachusetts.
authors: Nathan
authors: N
authors: Bennett
authors: Biomedical Imaging Research Institute, Cedars Sinai Medical Center, Los Angeles, California.|Department of Bioengineering, University of California, Los Angeles, California.
authors: Rohan
authors: R
authors: Dharmakumar
authors: Heart Institute.|David Geffen School of Medicine, University of California, Los Angeles, California.
authors: Sumeet S
authors: SS
authors: Chugh
authors: Heart Institute.
authors: Xunzhang
authors: X
authors: Wang
mesh_terms: D000818:Animals; D055424:Cardiac-Gated Imaging Techniques / Q000379:methods*; D002921:Cicatrix / Q000503:physiopathology*; D003287:Contrast Media; D004195:Disease Models, Animal; D004285:Dogs; D004562:Electrocardiography; D019786:Gadolinium DTPA; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009203:Myocardial Infarction / Q000503:physiopathology*; D017180:Tachycardia, Ventricular / Q000503:physiopathology*
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA
keywords: electroanatomical mapping; late potentials; magnetic resonance imaging; ventricular scar; ventricular tachycardia
references: J Am Coll Cardiol. 2001 May;37(6):1590-7
references: 11345370
references: Circ Arrhythm Electrophysiol. 2011 Feb;4(1):49-55
references: 21131557
references: J Am Coll Cardiol. 1990 Jun;15(7):1594-607
references: 2345240
references: Circulation. 2012 May 8;125(18):2184-96
references: 22492578
references: Circulation. 2004 Oct 26;110(17):2568-74
references: 15492309
references: Circ Arrhythm Electrophysiol. 2012 Apr;5(2):417-24
references: 22392447
references: J Am Coll Cardiol. 2004 Dec 21;44(12):2383-9
references: 15607402
references: Circulation. 1998 Nov 10;98(19):2055-64
references: 9808605
references: J Interv Card Electrophysiol. 2013 Apr;36(3):233-42
references: 23179916
references: Circulation. 2008 Dec 16;118(25):2773-82
references: 19064682
references: Circulation. 1999 Oct 19;100(16):1744-50
references: 10525495
references: J Am Coll Cardiol. 2008 Sep 2;52(10):839-42
references: 18755347
references: J Am Coll Cardiol. 2006 May 16;47(10):2013-9
references: 16697318
references: Heart Rhythm. 2010 Dec;7(12):1817-24
references: 20682358
references: Heart Rhythm. 2006 May;3(5):503-12
references: 16648052