Automatic implantable cardioverter-defibrillators

Ventricular fibrillation, a loss of synchronus electrical activity in the h eart which leads to hemodynamic collapse, is a leading cause of death. Beca use of the devastating personal and societal effects of this phenomenon, th e automatic cardioverter-defibrillator has been developed for automatic det ection and termination of the arrhythmia and is in widespread clinical use. Advances in circuits, leads, waveforms, and signal processing along with i ncreased knowledge of the mechanisms of fibrillation have led to continuing improvements in this device, extending its use to many patients. A device has also been developed for the automatic or semiautomatic treatment of atr ial fibrillation, an arrhythmia less life-threatening than ventricular fibr illation, but still a serious health problem. Continued improvement of thes e devices and the development of qualitatively new approaches hold great pr omise for exciting therapeutic advances in this area.