Original Contribution
Amplitude screening improves performance of AMSA method for predicting success of defibrillation in swine model☆

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Abstract

Purpose

A novel amplitude screening method, termed Optimal Amplitude Spectrum Area (Opt-AMSA) with the aim of improving the performance of the Amplitude Spectrum Area (AMSA) method, was proposed to optimize the timing of defibrillation. We investigated the effects of the Opt-AMSA method on the prediction of successful defibrillation when compared with AMSA in a porcine model of ventricular fibrillation (VF).

Method

60 male domestic pigs were untreated in the first 10 min of VF, then received cardiopulmonary resuscitation (CPR) for 6 min. Values of Opt-AMSA and AMSA were calculated every minute before defibrillation. Linear regression was used to evaluate the correlation between Opt-AMSA and AMSA. Receiver Operating Characteristic (ROC) analysis was conducted for the two methods and to compare their predictive values.

Results

The values of both AMSA and Opt-AMSA gradually decreased over time during untreated VF in all animals. The values of both methods of defibrillation were slightly increased after the implementation of CPR in animals that were successfully resuscitated, while there were no significant changes in either method in those who ultimately failed to resuscitate. The significant positive correlation between Opt-AMSA and AMSA was shown by Pearson correlation analysis. ROC analysis showed that Opt-AMSA (AUC = 0.87) significantly improved the performance of AMSA (AUC = 0.77) to predict successful defibrillation (Z = 2.27, P < 0.05).

Conclusion

Both the Opt-AMSA and AMSA methods showed high potential to predict the success of defibrillation. Moreover, the Opt-AMSA method improved the performance of the AMSA method, and may be a promising tool to optimize the timing of defibrillation.

Introduction

Ventricular fibrillation (VF) is typically the primary rhythm of cardiac arrest [1,2]. Currently, the most effective treatment to terminate VF is electrical defibrillation [3]. However, repetitive unsuccessful defibrillations may damage the myocardium due to high energy levels released by defibrillation. Therefore, the total number of defibrillation attempts should be minimized [2,4,5].

To improve defibrillation success rates, several methods based on electrocardiograms (ECGs) are undertaken to optimize the timing of defibrillation. The Amplitude Spectrum Area (AMSA) is one of the common predictors of the success of defibrillation [[6], [7], [8]], and is proven to be one of the most accurate [[9], [10], [11]].

There are many advantages of the AMSA method, including a high AUC value and high correlation with coronary perfusion pressure (CPP) [12]. The AMSA method is based on a wide frequency range from 4 Hz to 48 Hz, which might introduce electromyograms (EMGs) and other factors into its calculation [13]. Therefore, we hypothesized that there are some interferences mixed with an effective ECG signal. It may benefit the optimization of defibrillation timing to filter out irrelevant information.

Motivated by this, we introduced a new method we named Optimal Amplitude Spectrum Area (Opt-AMSA) to improve the performance of AMSA and to better predict the success of defibrillation. In the present retrospective porcine study, we compared the effectiveness and accuracy of AMSA and Opt-AMSA to predict successful defibrillation.

Section snippets

Methods

A total of 60 male domestic pigs weighing 40 ± 5 kg were included in this retrospective study. All animal experiments were approved by the Institutional Animal Care and Use Committee of the Tang Wanchun Laboratories of Emergency & Critical Care Medicine at Sun Yat-sen Memorial Hospital, Sun Yat-sen University. All animal experiments were conducted from November 2015 to November 2017.

Results

Among the 60 animal samples included in this retrospective study, successful first defibrillation was achieved for 29 (48%), while the other 31 (52%) failed to resuscitate. Fig. 2 shows the decrease in value of each method over time during untreated VF. Fig. 3 shows the increase in value of Group R, in each method, after the implementation of CPR. The comparison between Group R and Group N using the Opt-AMSA method shows significant differences in PC3(the third minute during precardiac

Discussion

Clinical and animal experiments have confirmed that a higher AMSA reflects higher myocardial energy and a higher probability of a successful defibrillation. In the present study, we proposed a new Opt-AMSA method for predicting the success of defibrillation. We found that Opt-AMSA maintains the same trend as AMSA over time. We also demonstrated that the Opt-AMSA method is highly correlated with AMSA, which is based on frequency domain. According to the analysis of ROC curves, both methods

Conclusion

Both the Opt-AMSA and AMSA methods show high potential to predict the success of defibrillation. The Opt-AMSA method improves the performance of the AMSA method, and provides a promising tool to optimize the timing of defibrillation.

Competing interests

The author declares that there are no competing interests regarding the publication of this manuscript.

Funding

This study was supported by research grant from the project of Leading Talents in Pearl River Talent Plan of Guangdong Province (No.81000-42020004) and the project Guangzhou Science and Technology Plan (No. 201804010471).

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    • Cited by (0)

    ☆

    The work was performed at Tang Wanchun Laboratories of Emergency & Critical Care Medicine, Guangzhou, China.

    1

    Contributed equally.

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    © 2018 Published by Elsevier Inc.