Implantable Cardioverter-Defibrillator Indications

Initially, ICDs were placed for hemodynamically significant VT or VF ( Table 35-8 ). Newer indications associated with sudden death include: awaiting heart transplant,^[81] long Q-T syndrome,^[82] Brugada syndrome (right bundle branch block, S-T segment elevation in leads V1-V3), and arrhythmogenic right ventricular dysplasia.^{[83] [84]} Studies suggest that ICDs can be placed prophylactically (i.e., used for primary prevention) to prevent sudden death in young patients with hypertrophic cardiomyopathy, ^[85] as well as post-MI patients with ejection fraction less than 30%,^[72] but are of no benefit post coronary artery bypass grafting. Three-chamber ICDs have been FDA approved for patients with dilated cardiomyopathy, and ICDs are in clinical trial for patients with HOCM who have experienced VT or VF.