We report a case where a 16-year-old girl with diabetes who suffered aborted cardiac arrest. Out of hospital the patient received a shock from an automated external defibrillator (AED) due to ventricular fibrillation (VF). Neither the VF nor the shock were reported to the receiving hospital. After referral to another hospital the AED transcript was read and the patient received an implantable cardioverter-defibrillator. Transcripts from AEDs used in the resuscitation of patients with cardiac arrest should always be analysed in order to optimize the diagnostic process and secure correct treatment.