Except you cannot know if the patient is flat-lined or has arrhythmia. The AED performs an ECG and delivers a shock only if appropriate; if you have one availab

Except you cannot know if the patient is flat-lined or has arrhythmia. The AED performs an ECG and delivers a shock only if appropriate; if you have one available, you should always use it (which does not exclude CPR in the meantime).