[Totally subcutaneous defibrillator]

Abstract

The implantable cardioverter-defibrillators (ICD) is a therapy for the prevention of sudden cardiac death. Complications with implant have been associated mainly with transvenous lead insertion. Difficulties in achieving venous access can occasionally result in failed ICD implantation. Lead failures remains a major limitation and often require removal. This procedure is associated with important morbidity and mortality. To eliminate the need for venous access, Bardy et al. designed an entirely subcutaneous ICD system. The subcutaneous ICD consists of a 3-mm tripolar parasternal electrode positioned parallel to the left of the sternal midline and guided exclusively by anatomical landmarks without fluoroscopy. The pulse generator is positioned over the sixth rib between the midaxillary line and the anterior axillary line. The device delivers a maximum of only 80-J shocks. Ventricular fibrillation was converted twice in 58 of 59 patients (98%) with the delivery of 65-J shocks in two tests to ensure a margin of safety. A demand pacing at 50 beats per minute is available for 30 seconds after a shock. These studies are preliminary but the system will need to be employ in a long-term, randomized, prospective, multicenter clinical trials.