Association between symptoms of depression and anxiety with heart rate variability in patients with implantable cardioverter defibrillators

Objective: This study investigated whether depression and anxiety symptoms are associated with measures of autonomic nervous system dysfunction in patients with implantable cardioverter defibrillators who are at high risk of cardiac rhythm disturbances. Depression and anxiety are associated with autonomic nervous system dysfunction, which may promote the risk of malignant cardiac arrhythmias. METHODS:: Patients with an implantable cardioverter defibrillator (ICD) underwent ambulatory electrocardiographic (ECG) monitoring (n = 44, mean age = 62.1 ± 9.3 years). Depression was assessed using the Beck Depression Inventory and anxiety was evaluated using the Taylor Manifest Anxiety Scale. Heart rate variability was assessed using time (RMSSD, pNN50, and SDNN) and frequency domain measures derived from 24-hour R-R intervals. Multivariate models were adjusted for age, sex, hypertension, diabetes, and smoking status. RESULTS:: Defibrillator patients with elevated depression symptoms (n = 12) had significantly lower RMSSD (15.25 ± 1.66 ms versus 24.97 ± 2.44 ms, p = .002) and pNN50 (1.83 ± 0.77 versus 5.61 ± 1.04, p = .006) than defibrillator patients with low depression symptoms (n = 32). These associations remained significant after multivariate adjustment for covariates. ICD patients with high anxiety levels (n = 10) displayed lower RMSSD (p = .013), which became marginally significant when adjusting for covariates (p = .069). CONCLUSIONS:: Depression and anxiety in defibrillator patients are associated with autonomic nervous system dysfunction indices of reduced parasympathetic control. Autonomic nervous system dysfunction may partially explain the association between depression and anxiety with life-threatening cardiac outcomes in vulnerable patients.