This app is intended for use by healthcare professionals who deliver training in cardiopulmonary resuscitation with the use of an automated external defibrillator (AED). It is a training aid only and is of no value in a real cardiac arrest situation. It is possible to set a practically unlimited sequence of shockable and non-shockable rhythms, and to reduce the length of the training cycle below 2 minutes where training time is limited. It is designed to work on both the iPhone and iPad.