Effects of Dopamine-Agonist Timing on Heart-Rate Variability and Orthostatic Hypotension in Parkinson Disease

Abstract

Alterations in autonomic nervous system (ANS) function and susceptibility to orthostatic hypotension (OH) have been reported in individuals with Parkinson disease (PD). Heart rate variability (HRV) can be used to provide a noninvasive evaluation of ANS effects on cardiac activity. PURPOSE: To determine the relationship between Levadopa and/or other dopamine-agonists (LDA) on HRV and OH in individuals with PD as compared to healthy elderly controls. METHODS: Eleven individuals with PD (10 males, 1 female; mean age 73.0 ± 9.57 yrs) participating in a PD exercise program and 9 age-matched controls (4 male, 5 female; mean age 65.3 ± 5.74 yrs) participated in this study. A 5-minute frequency domain HRV analysis was obtained in the supine position after 10 minutes of rest. Following this period, automated BP measurments were obtained at rest, immediately after standing (BPis), and after 2.5 minutes of continued standing (BP2.5min). Two hours after the initial assessment, all measurements were repeated on PD participants to examine LDA timing. Group comparisons were made using t-tests. RESULTS: No significance difference in HRV and BP measurements was found between LDA low and peak efficacies in the PD participants. A significant reduction in the logarithmic value of the high frequency component of HRV (ln HF) and BPis was found at LDA low efficacy in the PD participants when compared to controls.TableCONCLUSIONS: These results suggest that although periods of peak or low LDA efficacy does not influence ln HF or the BP response to orthostatic stress in PD participants, when compared to controls, the ln HF and BPis was significantly reduced during the period of low LDA efficacy.