Comparison: By using AECDs we will evaluate if an automatic, rapid, accurate and specific diagnostic technology will further increase the rate of survival in patients with VT/VF by rapid and automatic defibrillation, independent of operator initiation, as compared to standard cardiopulmonary resuscitation (CPR) with conventional defibrillators initiated by healthcare providers. This trial will be a randomized, controlled trial and will test if AECDs can improve outcome measures when compared to traditional responses.