Abstract 19204: Symptoms of Depression and Posttraumatic Stress Disorder are Associated with Differential Autonomic Influences to Standing

Abstract

Introduction: Depression and posttraumatic stress disorder (PTSD) are associated with impaired baroreflex sensitivity, a risk factor for sudden death. Unlike depression, PTSD is associated with hyperarousal. We hypothesized that, in patients with CAD, depressive and PTSD symptoms associate with different autonomic responses to standing (baroreflex response). Methods: We examined 178 patients with CAD for autonomic dysfunction with the ANSAR test (ANX 3.0, ANSAR Inc. Philadelphia, PA) in which heart rate variability was measured in both sitting (5 minutes) and standing (5 minutes) positions. Sympathetic (SNS) and parasympathetic (PNS) nervous system activity was measured using continuous wavelet transform and log-transformed. PTSD symptoms were assessed using the PTSD checklist scale (PCL), and depressive symptoms were assessed using the Beck Depression Inventory-II (BDI). Both BDI and PCL were examined in multivariate models simultaneously, adjusting for CAD risk factors, beta blockers, and antidepressants. Results: The mean (SD) age, BDI, and PCL scores were 62.4 (9.1), 7.2 (7.6), and 26.2 (10.2), respectively. For the group as a whole, the mean baseline SNS and PNS tones were -0.49 and -0.60 log beats per minute squared (log BPM 2 ). In multivariable models, PCL score associated with higher baseline SNS tone (β=0.03, p=0.046). With standing, PCL score associated with decrease in the levels of SNS tone (β=-0.02, p=0.02) vs. sitting, and BDI associated with an increased PNS tone (β=0.03, p=0.03) vs. sitting. In both cases, these responses are the opposite of the expected autonomic response to standing, which is an increase in SNS tone and decrease in PNS tone vs. sitting. Conclusion: Depressive and PTSD symptoms have opposite autonomic pathologies in CAD patients. While PTSD symptoms are associated with higher SNS tone at baseline, they are also associated with lower sympathetic activation with standing. Depressive symptoms, on the other hand, are associated with reduced vagal withdrawal with standing. This suggests that both depressive and PTSD symptoms are associated with an abnormal baroreceptor function, but through different autonomic pathways.