SN instructed about the Lifevest wearable defibrillator . Is a treatment option for sudden cardiac arrest that offers patients advanced protection and monitoring as well as improved quality of life. The Lifevest is the first wearable defibrillator. Unlike an implantable cardioverter defibrillator ( ICD ), the Lifevest is worn outside the body rather than implanted in the chest. This device continuously monitors the patient's heart with dry, non-adhesive sensing electrodes to detect life - threatening abnormal heart rhythms. If a life - threatening rhythm is detected, the device alerts the patient prior to delivering a treatment shock, and thus allows a conscious patient to delay the treatment shock. If the patient becomes unconscious, the device releases a Blue™ gel over the therapy electrodes and delivers an electrical shock to restore normal rhythm.