Implantable Cardioverter-Defibrillator

An implantable cardioverter-defibrillator, or ICD, is a device implanted inside the body that can perform defibrillation and, depending on the model, cardioversion and pacing of the heart, and it serves as a first-line treatment for patients at risk of sudden cardiac death from dangerous heart rhythms. It continuously monitors heart rate and rhythm and delivers an electrical shock once the heartbeat crosses a preset threshold, and more advanced versions attempt to distinguish between different types of dangerous rhythm and can use pacing to interrupt one before it becomes life-threatening. The cardiologist Michel Mirowski began developing the ICD at Sinai Hospital in Baltimore in 1969 together with Morton Mower and other colleagues, and the first human implantation took place in February 1980 at Johns Hopkins Hospital, performed by Levi Watkins Jr. A typical ICD battery lasts six to ten years, while its leads generally need replacement every five to ten years because of possible insulation failure or conductor fracture.