Although Implantable Cardioverter-Defibrillators (ICDs) are an established treatment for the prevention of death from ventricular arrhythmia, they require transvenous lead implantation and thus their insertion is prone to complications.\u00a0 If cardiac pacing is not also required, then potentially transvenous electrodes can be avoided altogether.\u00a0 The authors report the results of a novel subcutaneous ICD system designed to avoid the need for electrodes within or on the heart.
\nThe authors initially conducted two short-term clinical trials to find a suitable device.\u00a0 Four subcutaneous ICD configurations were tested in 78 patients and subsequently the best configuration was tested in an additional 49 additional patients to determine the optimal subcutaneous defibrillation threshold.\u00a0 Following this, the long-term use of subcutaneous ICDs were tested in a pilot study involving initially 6, then 55, patients.
\nA parasternal electrode and a left lateral thoracic pulse generator were found to constitute the optimal device, and this configuration was found to be as effective as a transvenous ICD for terminating ventricular fibrillation; however, a significantly higher mean energy requirement was needed (36.6J vs 11.1J).\u00a0 For those patients who received a permanent subcutaneous ICD, ventricular fibrillation was successfully detected in 100% of 137 episodes; after a mean of 10 months the device had successfully detected and treated all 12 episodes of spontaneous sustained ventricular tachycardia.<\/p>\n
Conclusions:
\nIn preliminary proof-of-concept studies, an entirely subcutaneous ICD device successfully detected and converted ventricular fibrillation and tachycardia.\u00a0 Larger scale clinical trials are now indicated.<\/p>\n
\u2022\u00a0\u00a0 \u00a0Bardy GH, Smith WM, Hood MA, Crozier IG, Melton IC, Jordaens L, et al. An entirely subcutaneous implantable cardioverter-defibrillator. N Engl J Med 2010, May 12.
\nJournals scanned
\nAmerican Journal of Medicine; American Journal of Physiology: Heart and Circulatory Physiology; Annals of Emergency Medicine; Annals of Thoracic Surgery; Archives of Internal Medicine; BMJ; Chest; European Journal of Cardiothoracic Surgery; JAMA; Journal of Clinical Investigation; Journal of Diabetes and its Complications; Journal of Immunology; Journal of Thoracic and Cardiovascular Surgery; Lancet; Nature Medicine; New England Journal of Medicine; Pharmacoeconomics; Thorax<\/p>\n
Reviewers
\nDr Alistair C Lindsay, Dr Hussain Contractor<\/p>\n","protected":false},"excerpt":{"rendered":"
Although Implantable Cardioverter-Defibrillators (ICDs) are an established treatment for the prevention of death from ventricular arrhythmia, they require transvenous lead implantation and thus their insertion is prone to complications.\u00a0 If cardiac pacing is not also required, then potentially transvenous electrodes can be avoided altogether.\u00a0 The authors report the results of a novel subcutaneous ICD system […]<\/p>\n