Document Detail

Distribution of late potentials within infarct scars assessed by ultra high-density mapping.
MedLine Citation:
PMID:  20682358     Owner:  NLM     Status:  In-Process    
BACKGROUND: Late potential (LP) electrograms represent areas of slow conduction and are often sites critical to reentrant tachycardia circuits. The distribution of LPs within infarct scar is not known.
OBJECTIVE: The purpose of this study was to delineate infarct heterogeneity using ultra high-density mapping and to determine the location of LPs with respect to scar architecture.
METHODS: Detailed endocardial (n = 21) and epicardial (n = 8) ultra high-density mapping was performed to delineate the substrate for ventricular tachycardia (VT) in 21 patients with ischemic cardiomyopathy. LP was defined as a low-voltage electrogram (< 1.5 mV) with distinct onset after the QRS. Very late potentials (vLPs) were classified as LPs with onset > 100 ms after the QRS.
RESULTS: A mean of 787 ± 391 and 810 ± 375 points in the LV endocardium and epicardium were sampled. Multipolar mapping identified heterogeneous islets (HIs) with relatively preserved electrogram amplitudes (≥ 0.51 mv) within dense scar (8.5 ± 4.9/4.5 ± 2.6 HIs per endocardium/epicardium) in all patients. In maps on which putative VT isthmuses were identified (25/29), 57% of vLP were recorded in or adjacent to HI. An LP-targeted ablation strategy combined with pace mapping achieved acute success in all patients (complete success in 52% and partial success in 48%). After 15 ± 7 months, 65% of patients remained free of VT episodes.
CONCLUSION: Ultra high-density mapping with a multipolar catheter facilitates the delineation of heterogeneous scar architecture at higher resolution. Electrograms within and adjacent to HIs have a higher incidence of vLP, and these sites are frequently critical to reentry. These findings have important implications for substrate-based ablation strategies.
Shiro Nakahara; Roderick Tung; Rafael J Ramirez; Jean Gima; Isaac Wiener; Aman Mahajan; Noel G Boyle; Kalyanam Shivkumar
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2010-08-01
Journal Detail:
Title:  Heart rhythm : the official journal of the Heart Rhythm Society     Volume:  7     ISSN:  1556-3871     ISO Abbreviation:  Heart Rhythm     Publication Date:  2010 Dec 
Date Detail:
Created Date:  2010-12-06     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101200317     Medline TA:  Heart Rhythm     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1817-24     Citation Subset:  IM    
Copyright Information:
Copyright © 2010 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.
UCLA Cardiac Arrhythmia Center, David Geffen School of Medicine at UCLA, Los Angeles, California 90095-1679, USA.
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