Document Detail

Lability of R- and T-wave peaks in three-dimensional electrocardiograms in implantable cardioverter defibrillator patients with ventricular tachyarrhythmia during follow-up.
MedLine Citation:
PMID:  20655057     Owner:  NLM     Status:  In-Process    
INTRODUCTION: From experiments, we know that the heterogeneity of action potential duration and morphology is an important mechanism of ventricular tachyarrhythmia. Electrocardiogram (ECG) markers of repolarization lability are known; however, lability of depolarization has not been systematically studied. We propose a novel method for the assessment of variability of both depolarization and repolarization phases of the cardiac cycle.
METHODS: Baseline orthogonal ECGs of 81 patients (mean ± SD age, 56 ± 13 years; 61 male [75%]) with structural heart disease and implanted single-chamber implantable cardioverter defibrillator (ICD) were analyzed. Clean 30-beat intervals with absence of premature beats were then selected. Baseline wandering was corrected before analysis. Peaks of R wave and peaks of T wave were detected for each beat, and the axis magnitude was calculated. The peaks were plotted to show clouds of peaks and then used to construct a convex hull, and the volumes of the R peaks cloud and T peaks cloud and ratio of volumes were calculated.
RESULTS: During a mean (SD) follow-up period of 13 (10) months, 9 of the 81 patients had sustained ventricular tachycardia or ventricular fibrillation (VT/VF) and received appropriate ICD therapies. All ICD events were adjudicated by three independent electrophysiologists. There was no statistically significant difference in the volume of T-wave peaks or R-wave peaks between patients with and without VT or VF during follow-up; however, R/T peaks cloud volume ratio was significantly lower in patients with subsequent VT/VF (22.4 ± 25.4 versus 13.1 ± 7.9, P = .024).
CONCLUSIONS: Larger volume of T peaks cloud, measured during 30 beats of three-dimensional ECG, is associated with higher risk of sustained ventricular tachyarrhythmias and appropriate ICD therapies. New method to assess temporal variability of repolarization in three-dimensional ECGs by measuring volume of peak clouds shows potential for further exploration for VT/VF risk stratification.
Lichy Han; Larisa G Tereshchenko
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Publication Detail:
Type:  Journal Article     Date:  2010-07-22
Journal Detail:
Title:  Journal of electrocardiology     Volume:  43     ISSN:  1532-8430     ISO Abbreviation:  J Electrocardiol     Publication Date:    2010 Nov-Dec
Date Detail:
Created Date:  2010-11-02     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0153605     Medline TA:  J Electrocardiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  577-82     Citation Subset:  IM    
Copyright Information:
Copyright © 2010 Elsevier Inc. All rights reserved.
Whiting School of Engineering, The Johns Hopkins University, Baltimore, MD 21287, USA.
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