Do patients at high risk of nonsudden cardiac death benefit from prophylactic ICD therapy?

Abstract

Randomized controlled trials have established that prophylactic implantable cardioverter defibrillator (ICD) therapy improves survival in patients with reduced left ventricular ejection fraction (LVEF). However, mortality reduction is not uniform across the implanted population and recent data have highlighted the importance of nonsudden cardiac death (non-SCD) risk in predicting benefit from ICD therapy. This review explores the importance of non-SCD risk in patient selection for prophylactic ICD therapy, as well as the proposed approaches to identify potential ICD recipients at high risk of non-SCD. Data from randomized controlled trials have demonstrated that patients at high risk of non-SCD do not gain significant survival benefit from prophylactic ICD therapy irrespective of their risk of SCD. A variety of strategies to identify low LVEF patients at high risk of non-SCD have been proposed. These include the use of individual risk markers, such as advanced age and renal dysfunction, the presence of cardiac and noncardiac comorbidities, and the use of more complex risk scores. Non-SCD risk is an important issue in patient selection for prophylactic ICD therapy. However, the optimal strategy to identify patients at high non-SCD risk is unclear and further research is needed.