Primary prevention implantable cardioverter defibrillators in non‐ischaemic cardiomyopathy: challenging the Australian heart failure guidelines

The implantable cardioverter defibrillator (ICD) has been shown to be a costeffective option for primary prevention of sudden cardiac death (SCD) in patients with heart failure with reduced ejection fraction (HFrEF). However, in the recently published 2018 guidelines for the prevention, detection and management of heart failure in Australia, the National Heart Foundation of Australia and Cardiac Society of Australia and New Zealand Heart Failure Guidelines Working Group downgraded the recommendation for primary prevention ICD to decrease mortality in patients with HFrEF and left ventricular ejection fraction (LVEF) 35% or below associated with nonischaemic cardiomyopathy (NICM).1,2 In particular, the level of recommendation and quality of evidence for primary prevention ICD was deemed weak and low for NICM versus strong and moderate for ischaemic cardiomyopathy, respectively. The document cited the lack of single randomised controlled trials demonstrating mortality benefits with primary prevention ICD in patients with NICM. It also highlighted recent prospective randomised controlled data of 1116 patients with HFrEF and LVEF 35% or below associated with nonischaemic causes from the DANISH trial — a Danish study to assess the efficacy of ICD in patients with nonischaemic systolic heart failure on mortality — whereby primary prevention ICD did not reduce mortality compared with usual clinical care over a median followup duration of 67.6 months (interquartile range, 49–85 months).3