Automated External Defibrillator

A portable device that automatically analyzes a collapsed person's heart rhythm through adhesive chest pads and, if it detects a shockable rhythm such as ventricular fibrillation, delivers an electric shock intended to let the heart's normal rhythm resume. Unlike the earlier hospital defibrillator, which required a trained operator to interpret an electrocardiogram and choose whether to shock, the automated version is designed for use by bystanders with minimal training, giving spoken step by step instructions and refusing to deliver a shock unless its own algorithm confirms one is appropriate. Devices of this kind reached wide civilian deployment beginning in the 1990s, placed in airports, offices, schools, and other public spaces as part of public access defibrillation programs intended to shorten the time between a cardiac arrest and the first shock, a delay strongly linked to survival. Because sudden cardiac arrest is often fatal within minutes without treatment, the device is generally used together with cardiopulmonary resuscitation performed by bystanders while waiting for emergency medical services to arrive.