Normalization of heart rate variability in post-traumatic stress disorder patients following fluoxetine treatment: Preliminary results

Background: Spectral analysis of heart rate variability has been shown to b e a reliable non-invasive test for quantitative assessment of cardiovascula r autonomic regulatory responses, providing a window reflecting the interac tion of sympathetic and parasympathetic tone. Alterations in autonomic func tion are associated with a variety of physiologic and pathophysiologic proc esses and may contribute substantially to morbidity and mortality. Our prev ious study shows that patients with posttraumatic stress disorder have sign ificantly lower HRV compared to controls, reflecting a basal autonomic stat e characterized by increased sympathetic and decreased parasympathetic tone . Objectives: To apply this tool to PTSD patients treated with selective sero tonin re-uptake inhibitors in order to assess the impact of such treatment on the autonomic dysregulation characterizing these patients. Methods: Standardized heart rate analysis was carried out in nine PTSD pati ents treated with SSRI agents and compared to that in a matched control gro up of nine healthy volunteers and in nine untreated PTSD patients, based on a 15 minute resting electrocardiogram. Results: Our preliminary results show that the HRV parameters indicating au tonomic dysregulation, which characterize PTSD patients at rest, are normal ized in responding patients by use of SSRIs. Neither the clinical implicati ons of these findings nor their physiological mechanisms are clear at prese nt, although we presume that they reflect a central effect, since the perip heral autonomic effects of SSRIs are relatively negligible.