Depression and autonomic nervous system dysfunction in patients with heart failure

Abstract

Background. Heart failure is a significant public health concern. It is the end stage for many heart related diseases and is a major cause of morbidity and mortality. Psychosocial variables influence disease outcomes. The full impact of psychosocial variables is unknown. The purpose of the study was to explore the interrelationship of degree of depression, heart rate variability (HRV), social support and quality of life (QOL) in patients with heart failure (HF) who had symptoms of mild to moderate depression. Methods. Secondary exploratory analyses were completed from a randomized controlled trial of heart failure patients (N=23) who were mildly to moderately depressed. Participants in the original study received Selective Serotonin Re-uptake Inhibitors (SSRI) or placebo. Instruments used in the trial included Beck Depression Inventory-II, Sarason Support Scale, Medical Outcomes Study 36-Item Survey, Version 2 and the Minnesota Living with Heart Failure Questionnaire. Results. At the end of the study after patients had received SSRI's or placebo, depression and amount of social support explained 50% of the variance of HRV parameter SDNN. A more parsimonious model illustrated that social support explained 33% of the variance. There was a moderate negative correlation between degree of depression and HRV. There was a moderate negative correlation between degree of depression and QOL. Patients who were depressed experienced more problems with physical functioning and symptoms from HF. Patients who received Selective Serotonin Re-uptake Inhibitors experienced improved HRV. Conclusion. When measuring quality of life in heart failure patients, depression measurement must be included. Psychosocial variables, most specifically social support, influence heart rate variability in heart failure patients; and thereby, theoretically impact mortality. As a result, further study is needed to explore the interaction of psychosocial variables and their impact on the autonomic nervous system in heart failure patients.