Non-ischemic cardiomyopathy in the elderly: A shocking conundrum

Abstract

The SCD-HeFT trial (Sudden Cardiac Death in Heart Failure Trial) in 2005 randomized patients with ischemic and non-ischemic heart failure to drug therapy with amiodarone and a single chamber implantable cardio-defibrillator(ICD). In a population consisting of 48% non-ischemic cardiomyopathy patients over a median follow-up of 45.5 months, ICDs reduced overall mortality by 23%. This trial along with several landmark randomized controlled trials(RCTs) endorsing the benefits of the ICD in patients with ischemic heart disease with reduced EF with and without electrical dyssynchrony [1,2], form the backbone of ICD implantation in patients satisfying ejection fraction(EF) criteria [3]. An independent advantage of providing protection, with the use of ICDs over and above the improvement in EF by electrical resynchronization, was also noted in patients with ischemic cardiomyopathy(ICM) [4,5]. In patients without this substrate, data from randomized controlled trials(RCT) is limited in addressing the benefits of the ICD independently over resynchronization therapy [6]. Hence a differential indication recommendation for both these substrates has been provided in the guidelines, when ICD implantation is planned for primary prevention (Class I for ischemic cardiomyopathy and Class II a for NICM) [7].