Comparison of the benefit of primary prophylactic implantable cardioverter-defibrillator on patients with ischemic cardiomyopathy and idiopathic dilated cardiomyopathy

BACKGROUND: Ischemic cardiomyopathy (ICM) and idiopathic dilated cardiomyopathy (DCM) shared common structural alterations with a high mortality from sudden cardiac death (SCD) and pump failure. Implantable cardioverter-defibrillator (ICD) has been confirmed both beneficial and cost-effective for primary prevention of SCD in patients with ischemic or non-ischemic heart diseases. The management of heart failure has improved due to the of implantation of ICD and cardiac resynchronization therapy-defibrillator (CRT-D). It remains unclear whether there is a difference in clinical effectiveness of primary prophylactic ICD implantation between patients with ICM and DCM. METHODS: We conducted a retrospective, single-center study, which enrolled 53 DCM patients and 25 ICM patients with guideline indications for primary prophylactic ICD or CRT-D treatment. Primary endpoint was all-cause mortality and secondary outcomes included cardiovascular death. RESULTS: During a median follow-up of 38.5 months, all-cause death occurred in 8 patients (32%) in the ICM group and 5 patients (9.43%) in the DCM group (P = 0.012). Cardiovascular death occurred in 5 patients (20%) in the ICM group and 3 patients (5.66%) in the DCM group (P = 0.052). Multivariable Cox regression analysis showed that cardiogenic mortality in the ICM group is higher than that in the DCM group (hazard ratio HR 0.119, 95% confidence interval (CI) 0.016 to 0.860, P = 0.035). CONCLUSIONS: Among patients who received ICD implantation for the primary prevention of SCD, there is no statistical difference in benefits between DCM and ICM patients. However, compared with DCM patients, ICM patients have a higher cardiovascular mortality, due to more exposure to risk factors.