A case of ventricular fibrillation not detected by an automated external defibrillator

We report a case of ventricular fibrillation (VF) which an automated external defibrillator (AED) could not detect. A 13-year-old girl collapsed just after playing basketball. Cardio pulmonary resuscitation (CPR) was started immediately and 5 minutes later an AED was applied by a rescue team. The monitor of the AED displayed typical VF, but the AED did not detect it as VF. The VF was not detected during 2 more attempts. Detection occurred on the fourth attempt, and counter-shock was successfully delivered, but the process took an extra 9 minutes. After the event, the girl was diagnosed with a latent type of prolonged QT syndrome. We analyzed the reason why the VF was not detected by the AED and found that the ECG detected by the AED fell outside the device’s parameters for ventricular tachycardia (VT) or VF. We emphasize that the AED is an excellent device, but we should also be aware of its limitations.