1. Scar voltage threshold determination using ex vivo magnetic resonance imaging integration in a porcine infarct model: Influence of interelectrode distances and three-dimensional spatial effects of scar.
- Author
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Tung R, Kim S, Yagishita D, Vaseghi M, Ennis DB, Ouadah S, Ajijola OA, Bradfield JS, Mahapatra S, Finn P, and Shivkumar K
- Subjects
- Animals, Cicatrix etiology, Cicatrix physiopathology, Disease Models, Animal, Imaging, Three-Dimensional methods, Swine, Tachycardia, Ventricular etiology, Tachycardia, Ventricular prevention & control, Cicatrix diagnostic imaging, Electrophysiologic Techniques, Cardiac methods, Magnetic Resonance Imaging methods, Myocardial Infarction complications, Myocardium pathology
- Abstract
Background: Studies analyzing optimal voltage thresholds for scar detection with electroanatomic mapping frequently lack a gold standard for comparison., Objective: The purpose of this study was to use a porcine infarct model with ex vivo magnetic resonance imaging (MRI) integration to characterize the relationship between interelectrode spacing and bipolar voltage thresholds and examine the influence of 3-dimensional scar on unipolar voltages., Methods: Thirty-two combined endocardial-epicardial electroanatomic maps were created in 8 postinfarct porcine subjects (bipolar 2-mm, 5-mm, and 8-mm interelectrode spacing and unipolar) for comparison with ex vivo MRI. Two thresholds were compared: (1) 95% normal distribution and (2) best fit to MRI. Direct electrogram analysis was performed in regions across from MRI-defined scar and adjacent to scar border zone., Results: A linear increase in optimal thresholds was observed with wider bipole spacing. The 95% thresholds for scar were lower than MRI-matched thresholds with moderate sensitivity for nontransmural scar (54% endo, 63% epi). Unipolar endocardial scar area exceeded MRI-defined scar, resulting in mismatched false scar in 5 of 8 (63%). Endocardial and epicardial unipolar voltages were lower than normal in regions adjacent and across from scar., Conclusion: Variations in interelectrode spacing necessitate tailored bipolar voltage thresholds to optimize scar detection. Statistical 95% thresholds appear to be conservative and not fully sensitive for the detection of scar defined by high-resolution ex vivo MRI. In the presence of endocardial scar, unipolar mapping to quantitatively characterize epicardial scar may be overly sensitive due to 3-dimensional spatial averaging., (Copyright © 2016 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)
- Published
- 2016
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