Implantable cardioverter-defibrillators in non-ischaemic cardiomyopathy: a need or not?

Excerpt

In the Netherlands, sudden cardiac death (SCD), usually caused by ventricular fibrillation, remains a major cause of mortality, with approximately 8000 cardiac arrests taking place outside the hospital annually (www.​hartstichting.​nl/​hart-en-vaatziekten/​cijfers-hart-en-vaatziekten). The majority of cases of SCD occur in subjects with an a priori low risk, as they outnumber the high-risk subjects in whom risk stratification and primary prevention of sudden death can be instituted [1]. Hence, aside from training lay public in basic life support and increasing access to public automatic defibrillators, our efforts in practice are aimed at SCD prevention in high-risk patients. Indeed, large randomised clinical trials have demonstrated that mortality can be reduced with implantable cardioverter-defibrillators (ICDs) in patients with a diminished left ventricular ejection fraction, both in primary and secondary prevention settings [2, 3]. In the Netherlands, the increased uptake of ICDs has subsequently reduced the chance of recording a shockable rhythm at cardiac resuscitation when compared with the pre-ICD era, indicating that a proportion of high-risk patients with an ICD are withdrawn from the group that is resuscitated [4]. Consequently, the guidelines of the European Society of Cardiology recommend implantation of an ICD in patients with ischaemic cardiomyopathy and a left ventricular ejection fraction (LVEF) of ≤ 35% despite at least 3 months of optimal medical heart failure therapy and a New York Heart Association (NYHA) class II or III, (class I, level of evidence A), and state that ICD implantation should be considered in patients with non-ischaemic cardiomyopathy, an LVEF of ≤ 35% despite optimal medical therapy and a NYHA class II or III (class IIA, level of evidence A) [5]. The latter recommendation represents a downgrade in recommendation compared with the 2015 recommendations, and this has been fuelled mostly by the DANISH study, which showed a trend in 1116 patients with non-ischaemic cardiomyopathy randomised to ICD or to no ICD after optimal medical therapy. ICD therapy in the DANISH study caused a significant reduction of SCD, but not in all-cause mortality (hazard ratio [HR] 0.87; 95% confidence interval [95% CI] 0.68–1.12; P = 0.28) [6]. Thus, there is discussion about the need for ICD therapy in patients with non-ischaemic cardiomyopathy in the modern era of advance heart failure medical therapy. …