title: Early abnormalities of vascular and cardiac autonomic control in Parkinson's disease without orthostatic hypotension.
abstract: Cardiac autonomic abnormalities have been described in Parkinson's disease. Little is known about possible alterations of vascular sympathetic regulatory activity in patients without orthostatic hypotension or symptoms of orthostatic intolerance. Nineteen patients with Parkinson's disease without orthostatic hypotension (PD), 21 with orthostatic hypotension (PDOH), and 20 healthy controls underwent ECG, beat-to-beat arterial pressure, and respiration recordings while recumbent and during a 75 degrees head-up tilt. Spectrum analysis of RR interval and systolic arterial pressure (SAP) variability provided indices of cardiac sympathovagal interaction (low frequency [LF]/high frequency [HF]) to the sinoatrial node and sympathetic vasomotor control (LF(SAP)). Arterial baroreceptor mechanisms were assessed by the spontaneous sequences technique and bivariate spectrum analysis (alpha index). Plasma catecholamines provided the neurohormonal profile. At rest, hemodynamics and spectral markers of autonomic function were similar in PD and control subjects. Norepinephrine was lower in PD and PDOH than in control subjects. In PDOH, SAP was higher, whereas LF/HF ratio and LF(SAP) were lower compared with control subjects. During tilt, SAP was unchanged in PD; however, similar to PDOH, the increase of heart rate, LF/HF ratio, and LF(SAP) was blunted compared with control subjects. Baroreflex indices were unmodified in PD and PDOH compared with control subjects. Initial alterations in both cardiac and vascular sympathetic modulatory activity were found in PD and revealed by a gravitational stimulus. Prompt recognition of sympathetic abnormalities might result in earlier therapeutic intervention, reduced orthostatic intolerance, and increased quality of life.
authors.affiliation: Medicina Interna II, Ospedale L. Sacco, Università degli Studi di Milano, Milan, Italy.
authors.forename: Franca
authors.initials: F
authors.lastname: Barbic
authors.forename: Francesca
authors.initials: F
authors.lastname: Perego
authors.forename: Margherita
authors.initials: M
authors.lastname: Canesi
authors.forename: Michela
authors.initials: M
authors.lastname: Gianni
authors.forename: Sara
authors.initials: S
authors.lastname: Biagiotti
authors.forename: Giorgio
authors.initials: G
authors.lastname: Costantino
authors.forename: Giovanni
authors.initials: G
authors.lastname: Pezzoli
authors.forename: Alberto
authors.initials: A
authors.lastname: Porta
authors.forename: Alberto
authors.initials: A
authors.lastname: Malliani
authors.forename: Raffaello
authors.initials: R
authors.lastname: Furlan
mesh_terms: D000368:Aged; D001342:Autonomic Nervous System Diseases / Q000209:etiology*; D001794:Blood Pressure; D002319:Cardiovascular System / Q000294:innervation*; D005260:Female; D006339:Heart Rate; D006801:Humans; D007024:Hypotension, Orthostatic / Q000097:blood / Q000209:etiology* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood; D010300:Parkinson Disease / Q000097:blood / Q000150:complications* / Q000503:physiopathology; D011187:Posture; D015656:Respiratory Mechanics; D013564:Sympathetic Nervous System / Q000503:physiopathology
chemical_list: D009638:Norepinephrine