Document Detail

Model of Bipolar Electrogram Fractionation and Conduction Block Associated with Activation Wavefront Direction at Infarct Border Zone Lateral Isthmus Boundaries.
MedLine Citation:
PMID:  24443512     Owner:  NLM     Status:  Publisher    
BACKGROUND: -Improved understanding of the mechanisms underlying infarct border zone (IBZ) electrogram fractionation may be helpful to identify arrhythmogenic regions in the post-infarction heart. We describe the generation of electrogram fractionation from changes in activation wavefront curvature in experimental canine infarction.
METHODS AND RESULTS: -A model was developed to estimate the extracellular signal shape that would be generated by wavefront propagation parallel to versus perpendicular to the lateral boundary (LB) of the reentrant ventricular tachycardia (VT) isthmus, or diastolic pathway. LBs are defined as locations where functional block forms during VT, and elsewhere they have been shown to coincide with sharp thin-to-thick transitions in IBZ thickness. To test the model, bipolar electrograms were acquired from IBZ sites in 10 canine heart experiments 3-5 days after experimental infarction. Activation maps were constructed during sinus rhythm and during VT. The characteristics of model-generated versus actual electrograms were compared. Quantitatively expressed VT fractionation (7.6±1.2 deflections, 16.3±8.9ms intervals) was similar to model-generated values with wavefront propagation perpendicular to the LB (9.4±2.4 deflections, 14.4±5.2ms intervals). Fractionation during sinus rhythm (5.9±1.8 deflections, 9.2±4.4ms intervals) was similar to model-generated fractionation with wavefront propagation parallel to the LB (6.7±3.1 deflections, 7.1±3.8ms intervals). VT and sinus rhythm fractionation sites were adjacent to LBs approximately 80% of the time.
CONCLUSIONS: -The results suggest that in a subacute canine infarct model, the LBs are a source of activation wavefront discontinuity and electrogram fractionation, with the degree of fractionation being dependent upon activation rate and wavefront orientation with respect to the LB.
Edward J Ciaccio; Hiroshi Ashikaga; James Coromilas; Bruce Hopenfeld; Daniel Cervantes; Andrew L Wit; Nicholas S Peters; Elliot R McVeigh; Hasan Garan
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2014-1-19
Journal Detail:
Title:  Circulation. Arrhythmia and electrophysiology     Volume:  -     ISSN:  1941-3084     ISO Abbreviation:  Circ Arrhythm Electrophysiol     Publication Date:  2014 Jan 
Date Detail:
Created Date:  2014-1-20     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101474365     Medline TA:  Circ Arrhythm Electrophysiol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
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