Autonomic dysregulation in panic disorder and in post-traumatic stress disorder: application of power spectrum analysis of heart rate variability at rest and in response to recollection of trauma or panic attacks

Power spectral analysis (PSA) of heart rate variability (HRV) offers reliab le assessment of cardiovascular autonomic responses, providing a 'window' o nto the interaction of peripheral sympathetic and parasympathetic tone. Alt erations in HRV are associated with various physiological and pathophysiolo gical processes, and may contribute to morbidity and mortality. Previous st udies of posttraumatic stress disorder (PTSD) found lower resting HRV in pa tients compared to controls, suggesting increased sympathetic and decreased parasympathetic tone. This article describes the analysis of HRV at rest a nd after psychological stress in panic disorder (PD) patients, in an enlarg ed sample of PTSD patients, and in healthy control subjects. Standardized h eart rate (HR) analysis was carried out in 14 PTSD patients, 11 PD patients and 25 matched controls. ECG recordings were made while subjects were rest ing ('rest 1'), while recalling the trauma implicated in PTSD, or the circu mstances of a severe panic attack, as appropriate ('recall'), and again whi le resting ('rest 2'). Controls were asked to recall a stressful life event during recall. While both patient groups had elevated HR and low frequency (LF) components of HRV at baseline (suggesting increased sympathetic activ ity), PTSD patients, unlike PD patients and controls, failed to respond to the recall stress with increases in HR and LF. HRV analysis demonstrates si gnificant differences in autonomic regulation of PTSD and PD patients compa red to each other and to control subjects. HRV analysis may augment biochem ical studies of peripheral measures in these disorders. (C) 2000 Elsevier S cience Ireland Ltd. All rights reserved.