How to use an AED, When the heart stops, a cardiac arrest has occurred. The most common cause is an abnormal rhythm of the heart, known as ventricular fibrillation. This abnormal rhythm can occur when the heart muscle is damaged because of a heart attack or when insufficient oxygen reaches the heart. A machine called an automated external defibrillator [AED] can be used to correct the heart rhythm by one or more electric “shocks··. AEDs are available in many public places, including shopping centers, railway stations, and airports. The machine analyses the casualty’s heart rhythm and shows with visual prompts – or tells you by voice prompts – what action…