Patient outcome after implant of a cardioverter defibrillator in the ‘real world’: the key role of co‐morbidities

Abstract

This article refers to 'The impact of co-morbidity burden on appropriate implantable cardioverter defibrillator therapy and all-cause mortality: insight from Danish nationwide clinical registers,' by A.C. Ruwald et al., published in this issue on pages 377-386.The use of implantable cardioverter defibrillators (ICDs) has significantly evolved in the last decades, following the pioneering experiences of Mirowski ∼35 years ago and related to very selected patients with a history of multiple cardiac arrests. 1 In a landmark trial on secondary prevention, the AVID trial, the ICD was found to be associated with a survival benefit, as compared with the control treatment group, which was affected by an occurrence of all-cause mortality of ∼25% at 2 years and 36% at 3 years. 2 In the setting of primary prevention, the efficacy of ICDs was initially established in patients with previous myocardial infarction and LV dysfunction (MADIT I, MUSTT, and MADIT II trials), 1,3 and was then extended to patients with LV dysfunction and heart failure (NYHA class II and III) of either ischaemic or non-ischaemic aetiology (SCD-HeFT trial). 3 In terms of relative risk, the benefits of ICD therapy were additional to optimized pharmacological treatment, and appeared even greater in primary than in secondary prevention trials (Figure 1).These findings were progressively translated into the recommendations for ICD implantation provided by consensus guidelines. Despite the solid evidence of benefit, the implementation of ICD therapy in the 'real world' was quite heterogeneous, and both financial and cultural issues could be considered in interpreting the extremely variable implant rates found in western countries and within Europe. 4 While the evidence in support of a benefit of the ICD in improving survival is quite solid in appropriately selected patients with ischaemic heart disease, some degree of uncertainty has always characterized the setting of non-ischaemic heart disease. The most recent guidelines on management of ventricular tachyarrhythmiasThe opinions expressed in this article are not necessarily those of the Editors of the European Journal of Heart Failure or of the European Society of Cardiology.

Highlights in heart failure

“…102 Neutral results may be caused by both the type of the intervention and patients selection. For instance, in a recent randomized controlled trial, remote monitoring through the CRTdefibrillator, compared with standard therapy, did not reduce mortality or hospitalizations, primary endpoint of the study, with, however, a reduction in in-office visits.…”

“…101,102,188,189 The contribution of comorbidities to patients' outcomes may be similar in patients with HFrEF, compared with those with HFpEF, 189 or be larger in those with HFpEF according to other analyses. 101,102,188,189 The contribution of comorbidities to patients' outcomes may be similar in patients with HFrEF, compared with those with HFpEF, 189 or be larger in those with HFpEF according to other analyses.…”

“…For instance, in a recent randomized controlled trial, remote monitoring through the CRTdefibrillator, compared with standard therapy, did not reduce mortality or hospitalizations, primary endpoint of the study, with, however, a reduction in in-office visits. 102 Neutral results may be caused by both the type of the intervention and patients selection. A network meta-analysis including 53 randomized controlled trials (12.356 patients) showed that, among services that decreased all-cause mortality and allcause readmissions after HF hospitalizations, nurse home visits were the most effective in both cases, compared with usual care.…”

Cardiac resynchronization therapy in the real world: need to upgrade outcome research

“…clearly show that patients who are candidates for upgrade to CRT have a different profile as compared to de novo CRT implant: they are older, with higher prevalence of coronary artery disease, valvular heart disease, chronic kidney disease, anaemia, and atrial fibrillation. Most of these factors have been found to be associated with a worse response to CRT and a worse outcome, leading to an important clinical question: ‘What is the long‐term outcome of these patients?’. Upgrade to CRT has never been the subject of a randomized clinical study but a recent systematic review and meta‐analysis identified a total of 16 reports including 489 568 CRT recipients, of whom 21 363 patients underwent an upgrade procedure.…”

“…The upgrade from a PM to a CRT-D is technically complex, and at least in non-ischaemic cardiomyopathy should occur less frequently in the future considering the mean age of patients with a previous implanted PM who are candidates for upgrade and the results of the DANISH trial. 4,17 The issue of atrioventricular node ablation in patients with atrial fibrillation who receive an upgrade to CRT is another important point, and it should be stressed that atrioventricular node ablation is crucial for achieving the full benefit of CRT (by ensuring >95% ventricular pacing) even if no RCT validated the strategy of atrioventricular node ablation combined with CRT. 18 The data reported by Linde et al 5 prevalence of coronary artery disease, valvular heart disease, chronic kidney disease, anaemia, and atrial fibrillation.…”