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Relation between ventricular fibrillation voltage and probability of defibrillation shocks. Analysis using Hilbert
A Patwardhan1, S Moghe, K Wang
1Division of Cardiology and Center for Biomedical Engineering, University of Kentucky, Lexington 40506-0070, USA.
Journal of Electrocardiology
|November 17, 1998
Summary
This study found that absolute ventricular fibrillation voltage (AVFV) is not a reliable predictor of defibrillation success. Analysis of electrocardiogram (ECG) envelopes did not show a stronger correlation than previous methods.
Area of Science:
- Cardiovascular physiology
- Medical engineering
- Electrophysiology
Background:
- Previous studies suggested a correlation between absolute ventricular fibrillation voltage (AVFV) and defibrillation shock outcome.
- Analysis methods evolved from single AVFV values to moving averages, influencing reported correlations.
Purpose of the Study:
- To re-evaluate the correlation between defibrillation shock outcome and AVFV using Hilbert transforms to estimate ECG envelopes.
- To compare the predictive power of envelope-derived AVFV against single values and moving averages.
Main Methods:
- Hilbert transforms were used to estimate ECG envelopes from orthogonal leads (X, Y, Z) in 11 dogs.
- Ventricular fibrillation was induced, followed by defibrillation shocks.
- 236 successful and 249 unsuccessful shock trials were analyzed.
Main Results:
- Moving average AVFV was not significantly higher in successful trials, contradicting prior findings.
- In the Z direction, unsuccessful trials showed higher voltage than successful trials (P < .05).
- Envelope-derived AVFV showed no consistent or statistically significant differences between successful and unsuccessful trials.
Conclusions:
- The absolute voltage of the electrocardiogram during ventricular fibrillation is not robustly correlated with defibrillation shock outcome.
- Methodological differences are unlikely to fully explain the discrepancy with previous studies.
- Envelope analysis using Hilbert transforms did not improve correlation predictability.