Depression as a predictor for appropriate shocks among patients with implantable cardioverter-defibrillators: Results from the Triggers of Ventricular Arrhythmias (TOVA) study

Abstract

OBJECTIVES: We sought to examine the relationship between symptoms of depression and shock-treated ventricular arrhythmias among implantable cardioverter-defibrillator (ICD) patients. BACKGROUND: Depression predicts mortality in patients with coronary artery disease (CAD), but whether this is via an increased risk of fatal ventricular arrhythmias is unclear. METHODS: We prospectively analyzed data on symptoms of depression and risk of ventricular arrhythmia (ventricular tachycardia/ventricular fibrillation [VT/VF]) resulting in ICD discharge in the Triggers of Ventricular Arrhythmias (TOVA) study. Symptoms were assessed by the Center for Epidemiologic Studies-Depression (CES-D) scale. Scores of 16 to 26 and <27 represented mild and moderate/severe depression, respectively. The Cox and Anderson-Gill proportional hazards models were used to test for associations among all patients and patients with CAD. RESULTS: Among 645 patients with baseline assessments, 90 (14%) were mildly depressed and 25 (3.9%) were moderately to severely depressed. Moderate/severe depression was associated with time to first shock for VT/VF (hazard ratio [HR] 3.2, 95% confidence interval [CI] 1.1 to 9.9) and all shocks for VT/VF including recurrent episodes (HR 3.2, 95% CI 1.2 to 8.6). Among the 476 CAD patients, the association with time to first shock (HR 6.4, 95% CI 1.9 to 21.1) and all shocks (HR 8.3, 95% CI 2.9 to 23.3) remained. The risk of shock for VT/VF was associated with depression severity in the total population (p for trend = 0.02) and among patients with CAD (p < 0.01), even after controlling for multiple confounders. CONCLUSIONS: More severe symptoms of depression predict shocks for VT/VF among ICD patients. The elevated risk of VT/VF among patients with CAD and depression suggests that arrhythmia may contribute significantly to total mortality in this subgroup. © 2005 by the American College of Cardiology Foundation.