Final answer:
An AED, or Automated External Defibrillator, is a portable device used to correct abnormal heart rhythms through an electric shock and is designed for use by laypersons in emergencies.
Step-by-step explanation:
The abbreviation that refers to an automatic defibrillator is AED, which stands for Automated External Defibrillator. These portable devices deliver a shock to a person's heart to correct abnormal heart rhythms, like ventricular fibrillation, which can occur during a heart attack. Defibrillators are capable of analyzing the patient's heart rhythm using an electrocardiogram and automatically administering the correct shock, with appropriate energy and waveform. They are designed to be easy to use, with verbal instructions, enabling laypersons to provide immediate assistance in a cardiac emergency; their presence in public places increases the chances of survival following a cardiac event. It is noteworthy that CPR is often recommended before using an AED.