Primary Prevention Implantable Cardioverter-Defibrillators

Abstract

The benefit of implantable cardioverter-defibrillators (ICDs) in improving mortality in populations at risk for sudden cardiac death has been firmly established by multiple randomized controlled trials (RCTs).1–3 However, patients receiving ICDs in clinical practice differ substantially from those enrolled in landmark RCTs. In the most recent report of the US National Cardiovascular Data Registry (NCDR) ICD Registry, including more than half a million ICD implants, ICD recipients were older and sicker, with higher prevalences of diabetes mellitus, hypertension, and atrial fibrillation, than those enrolled in the Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT) and the Multicenter Automatic Defibrillator Implantation Trial II (MADIT-II).1,3,4 Whether these patients enjoy a similar survival benefit to those enrolled in the clinical trials is less well understood. Determining the benefits of ICDs in the real world is a subject of increasing importance, especially as healthcare costs continue to rise. Article see p 706 In this issue of Circulation: Arrhythmias and Electrophysiology , Parkash et al5 compared the mortality rates in real-world patients in Nova Scotia receiving ICDs for primary prevention of ischemic or nonischemic cardiomyopathy (n=290) with comparable patients not receiving ICDs (n=601), using data from 2 registries. The study also described ICD utilization rates. They found that the ICD patients had significantly improved survival and also that ICD referral/implantation rates suggested significant underutilization. …