Effect of implantable cardioverter-defibrillator in non-ischemic heart failure according to heart failure etiology: Extended follow-up of the DANISH trial.

Background: Due to differences in clinical profiles and outcomes among patients with different causes of non-ischemic heart failure (HF), the risk of sudden cardiovascular death and the effect of implantable cardioverter-defibrillators (ICDs) may vary depending on HF etiology. We examined the effects of primary-prevention ICDs according to HF etiology in an extended follow-up study of DANISH (Danish Study to Assess the Efficacy of ICDs in Patients With Non-ischemic Systolic Heart Failure on Mortality).

Methods: DANISH randomized 1116 patients with non-ischemic HF to ICD implantation (N = 556) or usual care (N = 550). In this study, outcomes were analyzed by HF etiology.

Results: In total, 849 patients (76 %) had idiopathic HF, and 267 (24 %) had non-idiopathic HF (valvular, n = 41; hypertensive, n = 117; other, n = 109). During a median follow-up of 9.5 years, non-idiopathic HF was not associated with a significantly different rate of death from any cause (HR 1.03 [95 %CI,0.82-1.29]) or sudden cardiovascular death (HR 0.92 [95 %CI,0.55-1.55]) compared with idiopathic HF. Compared with usual care, ICD implantation did not reduce the rate of death from any cause in idiopathic (HR 0.89 [95 %CI,0.72-1.11]) or non-idiopathic HF (HR 0.86 [95 %CI,0.59-1.25]), with no interaction between HF etiology and treatment effect (P_interaction = 0.84). The beneficial effect of ICD implantation on sudden cardiovascular death was not modified by HF etiology (idiopathic: HR 0.60 [95 %CI,0.37-0.97]; non-idiopathic: HR 0.59 [95 %CI,0.24-1.48]; P_interaction = 0.99).

Conclusions: Rates of sudden cardiovascular death (or all-cause death) did not differ across different etiologies of non-ischemic HF. HF etiology did not modify the effects of primary-prevention ICD implantation compared with usual care.