Document Detail


Dynamic nature of electrocardiographic waveform predicts rescue shock outcome in porcine ventricular fibrillation.
MedLine Citation:
PMID:  12883511     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
STUDY OBJECTIVE: Survival decreases with duration of ventricular fibrillation, and it is possible that failed rescue shocks increase myocardial damage. Structure in the ECG signal during ventricular fibrillation can be quantified by using the scaling exponent, a dimensionless measure that correlates with ventricular fibrillation duration. This study examined whether the scaling exponent could predict rescue shock success and whether unsuccessful rescue shocks altered the structure of the ventricular fibrillation waveform and the responsiveness to subsequent rescue shocks. METHODS: Ventricular fibrillation was electrically induced in 44 anesthetized swine, which were randomly assigned to receive 70-J biphasic rescue shocks at 2, 4, 6, 8, or 10 minutes. If rescue shocks failed, up to 2 subsequent rescue shocks were performed at 2-minute intervals. The scaling exponent was calculated at 1-second intervals from ECG to quantify the organization of the ventricular fibrillation waveform. RESULTS: A total of 92 rescue shocks were delivered, of which 23 successfully converted ventricular fibrillation to an organized rhythm (immediate success). After these 23 rescue shocks, 14 swine sustained organized rhythms for more than 30 seconds (sustained success). Lower scaling exponent values were associated with increased probability of successful rescue shocks. Receiver operating characteristic curves had an area under the curve of 0.86 for immediate rescue shock success and 0.93 for sustained rescue shock success. Failed rescue shocks increased the rate of scaling exponent increase over time but did not appear to affect subsequent rescue shock success when the scaling exponent was taken into account. CONCLUSION: Highly deterministic ventricular fibrillation, reflected by a low scaling exponent, predicted rescue shock success regardless of antecedent failed rescue shocks. In addition, unsuccessful rescue shocks might decrease post-rescue shock ventricular fibrillation waveform organization.
Authors:
Christopher B Lightfoot; Nremt-P; Clifton W Callaway; Margaret Hsieh; Kristofer C Fertig; Lawrence D Sherman; James J Menegazzi
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Annals of emergency medicine     Volume:  42     ISSN:  0196-0644     ISO Abbreviation:  Ann Emerg Med     Publication Date:  2003 Aug 
Date Detail:
Created Date:  2003-07-28     Completed Date:  2003-08-22     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8002646     Medline TA:  Ann Emerg Med     Country:  United States    
Other Details:
Languages:  eng     Pagination:  230-41     Citation Subset:  AIM; IM    
Affiliation:
Department of Emergency Medicine, Center for Emergency Medicine of Western Pennsylvania, University of Pittsburgh, Pittsburgh, PA 15213, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
Cardiopulmonary Resuscitation* / adverse effects,  methods
Clinical Protocols
Data Interpretation, Statistical*
Discriminant Analysis
Disease Models, Animal*
Electric Countershock* / adverse effects,  methods
Electrocardiography / methods,  standards*
Female
Humans
Male
Predictive Value of Tests
ROC Curve
Random Allocation
Regression Analysis
Survival Analysis
Swine
Time Factors
Treatment Outcome
Ventricular Fibrillation / diagnosis*,  mortality,  therapy*

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


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