Implantable defibrillators for life threatening ventricular arrhythmias

Increasing numbers of patients are surviving a first episode of life threatening ventricular arrhythmia. In the absence of an acute myocardial infarction, patients who survive either ventricular fibrillation or sustained ventricular tachycardia have a high risk of further episodes, which may be fatal.1 Until recently class I and class III antiarrhythmic drugs have been the standard treatment for these patients, with amiodarone2 and sotalol3 having been shown to be superior to class I drugs. Nevertheless, even with the best medical therapy, arrhythmia recurrence rates are still 40-50% at five years. There is now growing evidence to support the wider use of implantable cardioverter-defibrillator devices as primary treatment in some patients with serious ventricular arrhythmias. These devices were developed in the 1970s, with the first human implant in 1980.4 Early devices had a single therapy option of defibrillation only; the generator was implanted abdominally; and thoracotomy was required for electrode placement. The units are now smaller (current devices are little bigger than a pacemaker) and can …