Abstract
AIMS: Guidelines recommend the use of implantable cardioverter-defibrillators (ICDs) to reduce the risk of sudden cardiac death (SCD) among individuals with heart failure (HF) with reduced ejection fraction (HFrEF). However, the magnitude of benefit from ICD therapy remains unclear in those with a non-ischaemic aetiology of HF. METHODS AND RESULTS: Participants with HFrEF and recent HF decompensation in the VICTORIA trial were categorized based on the utilization of a baseline ICD and HF aetiology. A propensity-score adjusted model was used to assess the effect of the presence of an ICD on SCD, cardiovascular death (including SCD) and all-cause death. Of 5040 participants with HFrEF (53.6% ischaemic; 46.4% non-ischaemic), 1399 (27.8%) had an ICD. Over a median of 10.8 months, pre-existing ICD was associated with an overall reduction in SCD (adjusted hazard ratio [aHR] 0.64, 95% confidence interval [CI] 0.43-0.96), but no difference in cardiovascular death (aHR 0.99, 95% CI 0.83-1.18) or all-cause death (aHR 1.02, 95% CI 0.87-1.19). HF aetiology did not modify the effects of ICD on SCD (ischaemic HF: aHR 0.61, 95% CI 0.38-0.98; non-ischaemic HF: aHR 0.72, 95% CI 0.36-1.43; p(interaction) = 0.69). Despite relative underuse of ICDs in women as compared to men (16.4% vs. 26.8%), women with an ischaemic cause of their HF had a significant reduction in SCD (aHR 0.2, 95% CI 0.05-0.82; p(interaction) = 0.029). The presence of atrial fibrillation modulated ICD treatment effect on SCD (p(interaction) = 0.015), with no benefit observed in those with atrial fibrillation. CONCLUSIONS: Among patients with HFrEF with recent decompensation, presence of an ICD was associated with a reduction in SCD, but did not translate to a reduction in the risk of cardiovascular or all-cause death. Future research is required to evaluate which patients with HFrEF benefit from ICD implantation.