Risk factors for short- and long-term adverse outcomes after syncope differed. Hospital admission favorably influenced syncope short term prognosis. Instead, 1-year mortality was unaffected by hospital admission and related to comorbidity.

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°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 (␣ 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.

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