Document Detail

Noninvasive electrocardiographic imaging of arrhythmogenesis: insights from modeling and human studies.
MedLine Citation:
PMID:  17993317     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: Sudden cardiac death remains the leading cause of death, claiming more than 1000 lives per day in the United States alone. Noninvasive means to diagnose rhythm disorders of the heart have relied heavily on the 12-lead electrocardiogram and, to a lesser extent, on higher-resolution body-surface mapping. These lack sensitivity and specificity due to the smoothing effect of the torso volume conductor. In contrast, noninvasive electrocardiographic imaging (ECGI) reconstructs potentials, electrograms, and activation sequences directly on the heart surface from body-surface electrocardiograms and has been applied in animal as well as clinical studies. This presentation summarizes the application of ECGI for imaging epicardial arrhythmogenic substrates and associated properties, in particular, dispersion of myocardial repolarization, fractionated electrograms, and heterogeneous multipolar potential distributions.
METHODS: Electrocardiographic imaging was evaluated in a canine model of temperature-induced dispersion of myocardial repolarization through localized warming and cooling and in 3 patients with preserved left ventricular ejection fraction (>or=50%) undergoing open heart surgery. Noninvasively reconstructed epicardial potentials, electrograms (and derived measures), as well as activation sequences were compared with their measured counterparts.
RESULTS: Epicardial measures of dispersion of repolarization (activation recovery intervals [ARIs] and QRST integrals) accurately reflected the underlying repolarization properties: prolonged ARIs and increased QRST (warming), shortened ARIs and decreased QRST (cooling), and gradients of adjacent prolonged and shortened ARIs (increased and decreased QRST) during simultaneous warming and cooling. In open-heart surgery patients, ECGI reflected the underlying arrhythmogenic substrate by noninvasively reconstructing fractionated electrograms (cross-correlation with measured electrograms = 0.72 +/- 0.25), regions of heterogeneous multipolar potential distributions, and areas of slow conduction.
CONCLUSION: These studies demonstrate that ECGI can capture and localize noninvasively important electrophysiologic properties of the heart. Its clinical significance lies in mapping arrhythmogenic substrates, evaluation and guidance of therapy, and risk stratification.
Raja N Ghanem
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural    
Journal Detail:
Title:  Journal of electrocardiology     Volume:  40     ISSN:  1532-8430     ISO Abbreviation:  J Electrocardiol     Publication Date:    2007 Nov-Dec
Date Detail:
Created Date:  2007-11-12     Completed Date:  2008-01-07     Revised Date:  2014-08-08    
Medline Journal Info:
Nlm Unique ID:  0153605     Medline TA:  J Electrocardiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  S169-73     Citation Subset:  IM    
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MeSH Terms
Arrhythmias, Cardiac / diagnosis*
Body Surface Potential Mapping / methods*
Computer Simulation
Diagnosis, Computer-Assisted / methods*
Diagnostic Imaging / methods*
Models, Cardiovascular*
Grant Support
R01 HL038408-13/HL/NHLBI NIH HHS; R01 HL049054/HL/NHLBI NIH HHS; R01 HL049054-16/HL/NHLBI NIH HHS; R01-HL-38408/HL/NHLBI NIH HHS; R01-HL-49054/HL/NHLBI NIH HHS; R37 HL033343-23/HL/NHLBI NIH HHS; R37-HL-33343/HL/NHLBI NIH HHS

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