The impact of shock therapy on depression development and remote prognosis in cardiac resynchronization therapy recipients.

Background: The aim of this study was to assess the incidence and clinical significance of depression in patients with cardiac resynchronization therapy with an implantable cardioverter-defibrillator (CRT-D). The study was also to evaluate the impact of shock therapy on depression development and long-term prognosis.

Methods: The prospective study encompassed 396 consecutive heart failure (HF) patients implanted with CRT-D. All patients completed the Beck Depression Inventory (BDI-II) and underwent a psychiatric examination at baseline. 221 patients free of depressive symptoms at baseline were included into the final analysis. The assessment of psychiatric status was routinely repeated every 6 months as well as after the shock delivery. The primary outcome was a composite endpoint of death or hospitalization for HF.

Results: During long-term observation (median 37.1 months) 52 (23.5%) patients suffered from an implantable cardioverter-defibrillator (ICD) shock, whereas 48 (21.8%) subjects developed depression. The incidence of new-onset depression was significantly higher in patients after shock delivery (Shock Group), CRT non-responders and subjects with atrial fibrillation. The risk for a composite endpoint was higher in the Shock Group than subjects without an ICD intervention: 57.7% vs. 25.4% and in patients with new-onset depression compared to the population free of this disorder: 62.5% vs. 24.9% (all p < 0.001). New-onset depression (HR 1.7) and an ICD shock (HR 2.1) were strong independent predictors of poor prognosis.

Conclusions: Depression is a common mental disorder in CRT-D recipients, that adversely affects long-term prognosis. Subjects suffering from ICD shocks and those with HF progression are at higher risk of experiencing depressive symptoms.