Primary prevention of sudden death with implantable defibrillator therapy in patients with cardiac disease: Can we afford to do it? (Can we afford not to?).

Abstract

Sudden cardiac death (SCD) is a major public health problem in North America, responsible for approximately 400 000 deaths annually.1,2 Most episodes of SCD in ambulatory populations result from ventricular tachyarrhythmias,3 whereas bradyarrhythmias may be important in some populations, notably hospitalized patients with advanced heart failure4 (Figure 1). A prior article in this series by Zipes and Wellens2 provides a detailed review of the pathogenesis of SCD, its underlying causes, and treatment strategies. Figure 1. Mechanisms of SCD in ambulatory persons. Most SCDs result from ventricular fibrillation. VT, bradyarrhythmias, and other mechanisms account for the remainder. ### ICD Therapy The availability of a therapy that reliably terminates the vast majority of life-threatening tachyarrhythmic and bradyarrhythmic events has tremendous clinical appeal. The implantable cardioverter defibrillator (ICD) represents such a therapy. Despite its appeal, the ICD is imperfect. Currently, systems are costly, have a limited life expectancy, and are subject to complications in the long term.5,6 Furthermore, many patients at risk for SCD are at risk of dying from causes that the ICD would not alter. The impact of ICD shocks also merits consideration. Evidence links multiple shocks with myocardial injury7 and fibrosis,8 and sporadic shocks are associated with significant, independent reductions in quality of life. Compared with patients not having shocks, patients in the Antiarrhythmics Versus Implantable Defibrillators (AVID) trial who had ≥1 shocks in the initial year of follow-up had significant declines in self-perceived physical functioning and mental well-being, independent of ejection fraction (EF), social circumstances, and medication use. The reduction in quality of life associated with shocks was of a magnitude similar to clinically important adverse effects from amiodarone.9 Cost-efficacy is a vital issue in settings of limited or restricted health care resources6 and is particularly relevant as ICD use is expanded to …