Cardiac resynchronisation therapy and implantable cardioverter-defibrillator in non-ischaemic systolic heart failure: extended follow-up of the DANISH trial

Background

In the Danish Study to Assess the Efficacy of Implantable Cardioverter-Defibrillators [ICDs] in Patients with Non-ischaemic Systolic Heart Failure on Mortality (DANISH) trial, ICD implantation did not provide an overall survival benefit in patients with non-ischaemic systolic heart failure. A high proportion of patients in the DANISH trial received a cardiac resynchronisation therapy (CRT) device, which improves the prognosis in patients with heart failure. Therefore, it is of interest to examine whether the effect of ICD implantation in patients with non-ischaemic systolic heart failure is modified by CRT.

Purpose

Adding 4 years of additional follow-up to the DANISH trial, we examined the effect of ICD implantation according to status with respect to CRT implantation at baseline.

Methods

In the DANISH trial, 556 patients with non-ischaemic systolic heart failure were randomised to receive an ICD and 560 to receive usual clinical care (control). Patients fulfilling indications for a CRT device received a CRT-defibrillator (if randomised to ICD arm) or CRT-pacemaker (if randomised to control arm). In the ICD group, 322 patients (57.9%) received a CRT device; in the control group, 323 patients (57.7%) received a CRT device. In this extended follow-up study, patients were followed until May 18, 2020. The primary outcome was death from any cause; secondary outcomes were cardiovascular death and sudden cardiovascular death.

Results

During a median follow-up of 9.5 years, the ICD group did not have significantly lower all-cause mortality compared with the control group (hazard ratio [HR] 0.89 [95% CI, 0.74–1.08]). The results were independent of whether the patient received a CRT device at randomisation (patients with a CRT device: HR 0.92 [95% CI, 0.72–1.18]; patients without a CRT device: HR 0.86 [95% CI, 0.64–1.14]; P for interaction, 0.72). Similarly, ICD implantation did not reduce rates of cardiovascular death overall (HR 0.87 [95% CI, 0.70–1.09]), and this association was not modified by CRT (patients with a CRT device: HR 0.89 [95% CI, 0.66–1.19]; patients without a CRT device: HR 0.85 [95% CI, 0.60–1.20]; P for interaction, 0.86). The ICD group had significantly lower rates of sudden cardiovascular death in the overall population (HR, 0.60 [95% CI, 0.40–0.92]), and this association was not modified by CRT (patients with a CRT device: HR 0.69 [95% CI, 0.40–1.21]; patients without a CRT device: HR 0.51 [95% CI, 0.26–0.97]; P for interaction, 0.47). See Figure 1 for all results.

Conclusions

In this extended follow-up study of the DANISH trial, the effect of ICD implantation in patients with non-ischaemic systolic heart failure was not modified by CRT.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): The DANISH trial was supported by unrestricted grants from Medtronic, St Jude Medical, Tryg Fonden, and the Danish Heart Foundation. No further funding was obtained for this follow-up study.

External cardioversion of atrial fibrillation and flutter in patients with cardiac implantable electrical devices

Funding Acknowledgements

Type of funding sources: None.

Introduction

Atrial tachyarrhythmias are often treated with external cardioversion (ECV) with direct current shocks in patients with potentially electrically sensitive cardiovascular implantable electronic devices (CIED). Long-term follow-up data on contemporary pacemakers and implantable cardioverter defibrillators (ICD) undergoing ECV is sparsely described. This study investigated shock-related complications and impact on CIEDs.

Methods

All ECV procedures of atrial fibrillation and flutter from 2010 to 2020 in patients with CIED performed at a tertiary hospital (Denmark) were identified in the Danish National Patient Registry. Data on device interrogation before and after ECV and procedure-related complications were retrieved retrospectively by review of medical records.

Results

We analysed 664 ECV-events performed in 362 CIEDs, median implant time 1.5 year. Mean age of patients at first ECV-event were 69.4±9.7 years and 72.2% were men. We identified two cases of major programming changes and two cases of premature battery depletion (≤3 years after generator implant) following ECV. Minor shock-related device changes were found for impedances, atrial sensing values and pacing thresholds of right ventricle lead. In two cases increased pacing threshold of right ventricle leads following ECV triggered exit-blocks after few months. No patients died due to shock-related device dysfunctions.

Conclusion

Following external cardioversion with transthoracic direct current shocks, sporadic (<1%) but potentially critical changes in device function were identified in patients with contemporary pacemakers and implantable cardioverter-defibrillators. The present study suggests that routine post-cardioversion device interrogation is imperative for patient safety.

P2627Diffuse coronary artery disease and effect of implantable cardioverter-defibrillators in patients with non-ischaemic systolic heart failure

Background

Implantable defibrillators reduce mortality in patients with ischaemic heart failure. The recent Danish Study to Assess the Efficacy of Implantable Cardioverter Defibrillators in Patients With Non-Ischaemic Systolic Heart Failure on Mortality (DANISH) found no overall effect on all-cause mortality with ICD implantation. Coronary artery disease (CAD) as the cause of heart failure had to be ruled out prior to inclusion into DANISH, but patients could have diffuse atherosclerosis, one- or two-vessel disease on the qualifying coronary angiogram if the investigator did not find that the degree of CAD could explain the severely reduced left ventricular ejection fraction. It is unknown if concomitant coronary atherosclerosis is related to outcome in patients with non-ischaemic cardiomyopathy and whether the effect of implanting an ICD is different in patients with non-ischaemic cardiomyopathy and coronary atherosclerosis.

Purpose

The aim of this study was to investigate the association between coronary atherosclerosis and all-cause mortality in patients with non-ischaemic systolic heart failure and the effect of ICD implantation in these patients.

Methods

Of the 1116 patients from the DANISH study, 838 patients with available coronary angiography data were included in this subgroup analysis. Patients were considered to have coronary atherosclerosis if the invasive cardiologist described diffuse atherosclerosis or coronary stenosis. We used cox regression to assess the relationship between coronary atherosclerosis and mortality and between ICD implantation and mortality in patients with and without coronary atherosclerosis. Data are presented as hazard ratios with 95% confidence intervals.

Results

Of the 838 patients, 266 (32%) had coronary atherosclerosis, 216 (81%) of whom were reported as having atherosclerosis without stenoses. Patients with coronary atherosclerosis were significantly older (median age 67 years vs 61 years), more often male (77% vs 70%) and had a higher prevalence of diabetes (30% vs 17%).

In univariable analysis, coronary atherosclerosis was a significant predictor of all-cause mortality (HR, 1.41; 95% CI, 1.04–1.91; P=0.03). However, the association between coronary atherosclerosis and all-cause mortality disappeared when adjusting for age, gender and diabetes (HR 1.02, 0.75–1.41, P=0.88). Adjusted hazard ratios are shown in Figure 1.

There was no association between ICD treatment and all-cause mortality in patients with or without coronary atherosclerosis (HR 0.94; 0.58–1.52; P=0.79 vs HR 0.82; 0.56–1.20; P=0.30), P for interaction=0.67.

Figure 1

Conclusions

In patients with non-ischaemic systolic heart failure, the concomitant presence of coronary atherosclerosis was associated with increased mortality. However, this association was not independent of other risk factors. ICD implantation was not associated with mortality risk in patients either with or without concomitant coronary atherosclerosis.

Acknowledgement/Funding

TrygFonden (Copenhagen, DK), Medtronic (US) and St. Jude Medical (US)

P4533Duration of heart failure and effect of defibrillator implantation in patients with non-ischemic systolic heart failure

Introduction

Patients with non-ischemic systolic heart failure have increased risk of sudden cardiac death (SCD) and death from progressive pump failure. Whether the risk of SCD changes over time is unknown. We seek to investigate the relationship between duration of heart failure, mode of death, and effect of implantable cardioverter defibrillator (ICD) implantation.

Methods

We examined the risk of all-cause death and SCD according to the duration of heart failure among patients with non-ischemic systolic heart failure enrolled in the Danish Study to Assess the Efficacy of ICDs in Patients with Non-ischemic Systolic Heart Failure on Mortality (DANISH) trial. Patients were divided according to quartiles of heart failure duration (Q1 ≤8 months, Q2 9 ≤18 months, Q3 19 ≤65 months, Q4 ≥66 months).

Results

A total number of 1116 patients were included. Patients with the longest duration of heart failure were older, more often men, had more comorbidity, and more often received cardiac resynchronizing therapy device. Doubling of heart failure duration was an independent predictor of both all-cause mortality (HR 1.26 95% CI 1.17–1.37, p<0.0001), and SCD (HR 1.29 95% CI 1.11–1.49, p=0.0009). The proportion of deaths caused by SCD was not different between heart failure quartiles (p=0.91), and the effect of ICD implantation on all-cause mortality was not modified by the duration of heart failure (p=0.59).

Duration of heart failure and death

Conclusions

Duration of heart failure predicted both all-cause mortality and risk of SCD independently of other risk indicators. However, the proportion of death caused by SCD did not change with longer duration of heart failure and the effect of ICD was not modified by the duration of heart failure.

Acknowledgement/Funding

The work was sponsored by The Danish Heart Foundation (Hjerteforeningen) and the Lundbeck Foundation (Lundbeckfonden). The DANISH trial was supported