Prediction of Defibrillation Outcome by Ventricular Fibrillation Waveform Analysis: A Clinical Review

Mi He

doi:10.4172/2155-9880.s10-009

Abstract

The most frequent initial rhythm in out-of-hospital witnessed cardiac arrest is ventricular fibrillation (VF) and electrical defibrillation is still the only effective therapy for the termination of this life-threatening cardiac arrhythmia. Even though earlier defibrillation is greatly emphasized during cardiopulmonary resuscitation (CPR), unnecessary or repetitive high energy defibrillations are associated with decreased post-resuscitation myocardial function. Optimizing the timing of defibrillation is of great importance in order to discriminate patients should receive immediate defibrillation versus alternate therapies such as CPR. Since characteristics of VF waveform changes over time and with CPR, which exhibit predictable ability of defibrillation success, quantitative analysis of VF waveform has the potential to guide defibrillation. This article reviewed methods developed for VF waveform analysis (including time domain, frequency domain, time-frequency domain, nonlinear analysis, and combination analysis techniques) and their performances for the prediction of defibrillation outcomes in clinical settings. The retrospective meta-analysis confirmed that VF waveform could predict the return of organized electrical activity, restoration of spontaneous circulation, and survival reliably. Additionally, predictors based on time-frequency and nonlinear methods were superior to other methods on the whole. However, no prospective studies have been performed to identify the optimal time of defibrillation utilizing VF waveform analysis until now. Therefore, the value of VF waveform analysis to guide clinical countershock management still needs further investigation.

Highlights

Ventricular fibrillation (VF), which is characterized as rapid and disorganized contractions of the heart with complex electrocardiogram (ECG) patterns, is the most frequent initial rhythm in out-of-hospital witnessed cardiac arrest (CA) [1]
Two definitions were commonly adopted in the studies of countershock prediction as standard of successful defibrillation: (1) defibrillation was considered to be successful with resulting in an organized rhythm seen at 5 second after delivery of the shock regardless of palpated pulsation of the common carotid artery by Koster et al [66]; (2) successful defibrillation was defined as those attempts which result in restoration of spontaneous circulation (ROSC) sustained for a period greater than 30 seconds and originating within a minute of the applied shock by Watson et al [49]
Recent clinical studies verified that it is possible to predict defibrillation success from the VF waveform with varying reliability

Summary

Introduction

Ventricular fibrillation (VF), which is characterized as rapid and disorganized contractions of the heart with complex electrocardiogram (ECG) patterns, is the most frequent initial rhythm in out-of-hospital witnessed cardiac arrest (CA) [1]. Electrical defibrillation, which consists of delivering of a therapeutic dose of electrical current to the fibrillating heart with the aid of a defibrillator, is still the only effective way to treat this life-threatening arrhythmia [2]. The probability of defibrillation success is inversely proportional to the duration of VF. Clinical data reported that for every minute passes between collapse and defibrillation, survival rates from witnessed VF decrease 7% to 10% if no cardiopulmonary resuscitation (CPR) is provided. With effective CPR, the success rate of rescue decreases 3-4% per minute [3]. Early CPR together with early defibrillation is a key point in the chain of survival

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