Comparative assessment of shockable ECG rhythm detection algorithms in automated external defibrillators
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1Institute for Biomedical Equipment Evaluation and Services, Sheffield, UK.
Insights
Automated external defibrillators (AEDs) and advisory defibrillators showed variable sensitivity and specificity in detecting shockable heart rhythms like ventricular fibrillation (VF) and ventricular tachycardia (VT). Performance varied based on rhythm classification and inclusion of artifact rhythms.
Area of Science:
- Biomedical Engineering
- Cardiology
- Medical Device Evaluation
Background:
- Automated external defibrillators (AEDs) and advisory defibrillators are crucial for managing sudden cardiac arrest.
- Accurate detection of life-threatening arrhythmias, specifically ventricular fibrillation (VF) and ventricular tachycardia (VT), is critical for effective defibrillation.
- The performance of these devices can be influenced by the complexity and artifact content of electrocardiogram (ECG) rhythms.
Purpose of the Study:
- To assess the sensitivity and specificity of four AEDs and three advisory defibrillators.
- To evaluate device performance using a comprehensive arrhythmia library, including rhythms with noise and interference.
- To determine the accuracy of shockable rhythm detection under various conditions.
Main Methods:
- Utilized the Department of Health Arrhythmia library, comprising 278 ECG rhythms (59 VF, 36 shockable VT, 183 non-shockable).
- Assessed AEDs by recording positive results if charging initiated for a shockable rhythm.
- Evaluated advisory defibrillators by recording positive results if a 'shock advised' alert was issued.
Main Results:
- AEDs demonstrated sensitivities for VF ranging from 81-94% and for VF plus shockable VT from 64-83%.
- Specificities for AEDs ranged from 86-94%, with slight variations based on VT rate thresholds.
- Advisory defibrillators showed similar performance, with specificities ranging from 79-91% when excluding artifact rhythms.
Conclusions:
- The study highlights variability in the sensitivity and specificity of AEDs and advisory defibrillators for detecting critical arrhythmias.
- Device performance is influenced by the specific arrhythmia and the presence of ECG artifacts.
- Further evaluation is necessary to ensure reliable performance across diverse clinical scenarios.
Abstract:
The sensitivity and specificity to ventricular fibrillation (VF) and ventricular tachycardia (VT), classified as requiring immediate DC shock, of four automated external defibrillators (AEDs) and three advisory defibrillators were assessed using the Department of Health Arrhythmia library. This library collected mostly from patients in hospital, includes a wide variety of ECG rhythms including many with additional noise and interference artefact. The library comprised 278 16-s rhythms, 59 of which were VF, 36 were VT requiring cardioversion and 183 were deemed non-shockable. Non-shockable rhythms included asystole, pacing, slow VT, idioventricular rhythms, sinus and atrial based rhythms, some of which contained ventricular ectopic activity of differing grades. For the AEDs, a positive result (indicating detection of a shockable rhythm) was recorded if charging started or was able to be started at any time during the 16 s of rhythm output and energy subsequently available for discharge. For the advisory defibrillators, a positive result was recorded if a 'shock advised' alert was issued at any time during output of the rhythm. The AEDs exhibited sensitivities to VF in the range 81-94%, and to VF plus shockable VT 64-73%, or 72-83% depending whether VT > 150 beats/min or > 180 beats/min is considered to be shockable. The specificities recorded were in the range 90-94% and 86-92%, respectively. All but one of the advisory defibrillators performed similarly. Excluding the artefact rhythms, specificities in the range 79-91% were obtained. All figures stated are at the lower limit of the 95% confidence interval.