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 s...

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Bibliographic Details
Published in:Circulation research 2007-10, Vol.101 (9), p.939-947
Main Authors: Ashikaga, Hiroshi, Sasano, Tetsuo, Dong, Jun, Zviman, M Muz, Evers, Robert, Hopenfeld, Bruce, Castro, Valeria, Helm, Robert H, Dickfeld, Timm, Nazarian, Saman, Donahue, J Kevin, Berger, Ronald D, Calkins, Hugh, Abraham, M Roselle, Marbán, Eduardo, Lardo, Albert C, McVeigh, Elliot R, Halperin, Henry R
Format: Article
Language:English
Subjects:
Animals
Biological and medical sciences
Cardiac dysrhythmias
Cardiology. Vascular system
Catheter Ablation - adverse effects
Cicatrix - etiology
Cicatrix - pathology
Cicatrix - physiopathology
Electrodes
Fundamental and applied biological sciences. Psychology
Heart
Magnetic Resonance Imaging - methods
Medical sciences
Myocardium - pathology
Sus scrofa
Tachycardia, Ventricular - etiology
Tachycardia, Ventricular - pathology
Tachycardia, Ventricular - physiopathology
Vertebrates: cardiovascular system
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Summary: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.
ISSN:0009-7330
1524-4571
DOI:10.1161/CIRCRESAHA.107.158980