Magnetic resonance-based anatomical analysis of scar-related ventricular tachycardia: implications for catheter ablation.
In catheter ablation of scar-related monomorphic ventricular tachycardia (VT), substrate voltage mapping is used to electrically define the scar during sinus rhythm. However, the electrically defined scar may not accurately reflect the anatomical scar. Magnetic resonance-based visualization of the scar may elucidate the 3D anatomical correlation between the fine structural details of the scar and scar-related VT circuits. We registered VT activation sequence with the 3D scar anatomy derived from high-resolution contrast-enhanced MRI in a swine model of chronic myocardial infarction using epicardial sock electrodes (n=6, epicardial group), which have direct contact with the myocardium where the electrical signal is recorded. In a separate group of animals (n=5, endocardial group), we also assessed the incidence of endocardial reentry in this model using endocardial basket catheters. Ten to 12 weeks after myocardial infarction, sustained monomorphic VT was reproducibly induced in all animals (n=11). In the epicardial group, 21 VT morphologies were induced, of which 4 (19.0%) showed epicardial reentry. The reentry isthmus was characterized by a relatively small volume of viable myocardium bound by the scar tissue at the infarct border zone or over the infarct. In the endocardial group (n=5), 6 VT morphologies were induced, of which 4 (66.7%) showed endocardial reentry. In conclusion, MRI revealed a scar with spatially complex structures, particularly at the isthmus, with substrate for multiple VT morphologies after a single ischemic episode. Magnetic resonance-based visualization of scar morphology would potentially contribute to preprocedural planning for catheter ablation of scar-related, unmappable VT.
Ashikaga
Hiroshi
H
Division of Cardiology, Johns Hopkins University School of Medicine, 720 Rutland Ave, Traylor 903, Baltimore, MD 20215, USA. ha8000@gmail.com
Sasano
Tetsuo
T
Dong
Jun
J
Zviman
M Muz
MM
Evers
Robert
R
Hopenfeld
Bruce
B
Castro
Valeria
V
Helm
Robert H
RH
Dickfeld
Timm
T
Nazarian
Saman
S
Donahue
J Kevin
JK
Berger
Ronald D
RD
Calkins
Hugh
H
Abraham
M Roselle
MR
Marbán
Eduardo
E
Lardo
Albert C
AC
McVeigh
Elliot R
ER
Halperin
Henry R
HR
D000818:Animals; D017115:Catheter Ablation / Q000009:adverse effects*; D002921:Cicatrix / Q000209:etiology* / Q000473:pathology* / Q000503:physiopathology; D004566:Electrodes; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009206:Myocardium / Q000473:pathology; D034421:Sus scrofa; D017180:Tachycardia, Ventricular / Q000209:etiology* / Q000473:pathology* / Q000503:physiopathology