An automatic external defibrillator (AED) is described which is designed for use in a single cardiac emergency. If the AED is in standby for a year without being deployed, the AED is removed from service and replaced with another AED. The AED requires a rescuer only to deploy the electrodes on the torso of the victim; the AED turns itself on, performs rhythm analysis and delivers a shock if needed automatically. The AED thus requires no user controls. Preferably the AED requires no on-site maintenance, as the AED communicates its readiness for use to a remote monitoring site which responds to any problems detected by self-testing. In addition to its electro-resuscitation function, the AED can be used on the chest of the victim to administer CPR compressions.