Prevalence and persistence of depression in patients with implantable cardioverter defibrillator: a 2-year longitudinal study

Abstract

Background: It is unclear whether depression persists in patients with implantable cardioverter defibrillators (ICDs). We evaluated the prevalence and persistence of depression in ICD patients over a 2-year period.

Methods: The study included 90 consecutively hospitalized patients. Patients underlying heart disease was 24% coronary artery disease, 29% idiopathic dilated cardiomyopathy, 24% hypertrophic cardiomyopathy, 13% idiopathic VF/long QT syndrome and miscellaneous conditions 11%. A secondary indication for ICD implantation was present in 20 patients. All patients completed the Zung Self-Rating Depression Scale (SDS) at study baseline and at the their routine follow-up visit 2 years after the baseline questionnaire. Delivery of ICD therapies was tracked throughout the 2 years.

Results: Depression, indicated by a Zung SDS index score exceeding 60, was present in 29 (32%) of patients at study baseline. Depression was present in 11/51 (21%) patients scheduled to undergo ICD implantation, 2/2 (100%) patients whose device was upgraded to a CRT-D, 3/14 (21%) patients who had undergone pulse generator replacement, 7/14 (50%) patients who experienced electrical storm and 6/9 (66%) patients hospitalized with acute decompensated heart failure. NYHA functional class III was significantly associated with depression at baseline (HR 6.7, 95% CI 1.68-27.2, p = 0.0007). No differences were noted for female gender, demographics, β-blocker use, or LVEF ≤35% (p = ns). Depression was present in 25 (28%) of patients at 2 years follow-up, persisting in 21 (72%) of patients whose Zung SDS scores were elevated at baseline. The median time from ICD shock therapy to completion of the 2 year questionnaire was 9 months (range, 1-22). Patients who were depressed (9/25, 36%) experienced more shocks than non-depressed patients (6/65, 9%) after 2 years (p = 0.002).

Conclusions: Depression is not uncommon among patients who meet criteria for ICD implantation and persists over time particularly when functional status is impaired. Depression is associated with a higher incidence shock therapy.