Document Detail


Relation between ventricular fibrillation voltage and probability of defibrillation shocks. Analysis using Hilbert transforms.
MedLine Citation:
PMID:  9817215     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We used Hilbert transforms to re-evaluate the previously reported correlation between defibrillation shock outcome and absolute ventricular fibrillation voltage (AVFV). Previously in the literature, single values of AVFV acquired just prior to shock delivery were used to show a correlation between AVFV and shock outcome. In subsequent studies, a modified analysis procedure was used to show a correlation between shock outcome and moving average of AVFV. The use of single values of AVFV makes the AVFV sensitive to the local phase of the electrocardiographic (ECG) waveform, whereas moving averages are weighted by previous values of the ECG. The envelope is independent of the phase of the ECG and is not weighted by previous values of ECG as is the moving average. We explored, therefore, whether the AVFV computed from the envelopes of the ECG showed a stronger correlation with shock outcome than single values and moving averages of the AVFV. We estimated envelopes using the Hilbert transform. Orthogonal ECGs (sagittal, X; transverse, Y; and longitudinal, Z) were recorded from 11 dogs during 10 seconds of electrically induced ventricular fibrillation followed by a defibrillation shock with 50% probability of success. We used transvenous (right ventricular apex to subcutaneous patch) leads to deliver defibrillation shocks. Results from 236 successful and 249 unsuccessful trials showed, in contrast with the previously reported correlation, that moving average of AVFV was not higher for successful trials. In the Z direction, unsuccessful trials had higher voltage than successful trials (P < .05). Comparison of envelope voltages between successful and unsuccessful trials did not show any consistent and statistically significant differences. Although there were some methodological differences between ours and the previously reported studies, they are unlikely to have caused the discrepant observations. Our results suggest, therefore, that the absolute voltage of ECG during ventricular fibrillation is not robustly correlated with shock outcome.
Authors:
A Patwardhan; S Moghe; K Wang; H Cruise; F Leonelli
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of electrocardiology     Volume:  31     ISSN:  0022-0736     ISO Abbreviation:  J Electrocardiol     Publication Date:  1998 Oct 
Date Detail:
Created Date:  1999-01-21     Completed Date:  1999-01-21     Revised Date:  2009-11-11    
Medline Journal Info:
Nlm Unique ID:  0153605     Medline TA:  J Electrocardiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  317-25     Citation Subset:  IM    
Affiliation:
Division of Cardiology and Center for Biomedical Engineering, University of Kentucky, Lexington 40506-0070, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
Disease Models, Animal
Dogs
Electric Countershock* / standards
Electrocardiography*
Female
Linear Models
Male
Risk Factors
Treatment Outcome
Ventricular Fibrillation / physiopathology*,  therapy

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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