P5430Long term outcomes of patients receiving Implantable Cardioverter Defibrillators in a contemporary implant population in the Essex region of the UK
Authors: Savage H O , Rao A , Li B , Langley S , Hansom S , Dungu J N , Tan S , Farwell D , Phen P , Harris S 
Published: October 2019

Abstract

Introduction
Implantable cardioverter-defibrillators (ICD) reduce the risk of sudden cardiac death in patients who are at risk and amongst among heart failure (HF) patients with a reduced left ventricular ejection fraction (LVEF).

Objective
The aim of this study was to determine the differences in outcomes amongst patients in a contemporary ICD implant population based on primary or secondary indications and an ischaemic or non-ischaemic aetiology. The primary outcome was death or appropriate device therapy for a ventricular arrhythmia. The secondary outcome was inappropriate shock therapy.

Purpose
The study cohort included consecutive patients who had an ICD or CRT-D implanted at a high-volume regional referral centre in Essex between 2014 and 2015. The censor point for follow up was 31/12/2018. Cumulative incidences were analysed by the method of Kaplan–Meier and compared using the log-rank test. In addition, the relationship between several clinical variables were tested in a multivariate Cox model to predict long-term mortality and this is described with hazard ratios (HR) and 95% CI.

Results
407 patients who received ICD treatment were followed up for a mean of 50±4 months. 63% had an Ischaemic cardiomyopathy and 60% had a primary prevention indication. Majority were men (81.5%), mean LVEF was (31±11) and mean age (71±11). The incidence of appropriate ICD therapy at 1-year post ICD insertion was 6.8% in all patients. This was significantly higher in patients with a secondary prevention indication compared to primary prevention (11.7% v 3.6% p=0.015) but similar in ischaemic compared to non-ischaemic patients (7.8% v 5.2% p=0.46). 1.9% patients had an inappropriate shock at 1 year and between group rate was similar. Overall 8.1% of patients did not survive beyond 1-year post implant with a mean time to death of 5.6±3.6 months. The cumulative incidence of the primary end-point at 1 year was similar in ischaemic and non-Ischaemic patients (7.8% v 8.6%; HR: 1.04, 95% CI 0.7–1.5, p=0.83) but was significantly higher at the end of study period in patients with an ischaemic aetiology (32.4% v 21%; HR: 1.59, 95% CI: 1.1–2.4, p=0.024) (Fig.1). In an adjusted Cox Hazard model, appropriate ICD therapy at 1 year (HR: 0.28, 95% CI: 0.17–0.47, p<0.001) and a secondary indication for ICD treatment (HR: 0.47, 95% CI: 0.31–0.73, p=0.001) were strongly associated with long-term mortality.
Figure 1

Conclusions
Our study highlights outcomes in a long-term follow up of ICD patients and in light of the debate around the DANISH trial, we have shown that at 1 year, the benefit of ICD therapy is comparable in non-ischaemic compared to ischaemic cardiomyopathies. Moreover, patients who had an ICD implanted for secondary prevention had a 3-fold mortality benefit at 1 year and had a higher rate of death. Appropriate ICD therapy and a secondary prevention indication predicted long term mortality.