Assessment of the ventricular fibrillation detection algorithm in the semi-automatic Cardio-Aid defibrillator.

The sensitivity and specificity of ventricular fibrillation (VF) detection in the semi-automatic Cardio-Aid defibrillator was assessed with 25 ECG recordings, each of length 40 s. Of the 25 ECG recordings, 12 contained VF requiring defibrillation, 3 contained a tachyarrhythmia with a waveform similar to VF but which self-terminated, and 10 were selected from abnormal rhythms and artefacts which contained some features similar to VF. Sensitivity was assessed from the VF data. Specificity was assessed from both the rhythm preceding VF or the tachyarrhythmias, and from the VF-like data. The response to a changing rhythm was assessed from the self-terminating tachyarrhythmias. Each recording was replayed to the defibrillators at 3 signal amplitudes (normal, half and double). Request to analyse the ECG because of possible VF and advice to shock were noted separately. The sensitivity for recommending a shock when a shock was required was 92%. The sensitivity for drawing attention to VF, through requesting analysis was 97%. There were no false detections in the rhythms preceding VF or the tachyarrhythmias (specificity with good quality signals 100%). The specificity with the VF-like data ws 90%. There was significant difference between this defibrillator and other semi-automated defibrillators previously assessed.