Syncope and autonomic cardiovascular dysfunction in Parkinson disease

Background and purpose: The aim of the study was to investigate the relationship between syncope or presyncope occurrence and dysfunction of the cardiovascular autonomic system in patients with Parkinson disease (PD). Material and methods: Twenty-four PD patients were studied, including 10 subjects with syncope/presyncope and 14 controls without those symptoms. Ambulatory blood pressure monitoring (ABPM), Holter electrocardiographic monitoring, carotid sinus massage, tilt test, and cardiac scintigraphy with (123)I metaiodobenzylguanidine (MIBG) were performed. Results: Differences between the two groups were found in myocardial scintigraphy and ABPM. The stepwise regression analyses suggest that the values of late phase reduced uptake of MIBG (95% CI: 0.0-0.77;p < 0.05) and daytime minimum systolic blood pressure (95% CI: 0.78-0.98; p = 0.007) may be related to the occurrence of syncope/presyncope. Conclusions: The findings suggest an association between syncope/presyncope occurrence and dysfunction of the cardiovascular autonomic system in PD patients. Both (123)I MIBG myocardial scintigraphy and ABPM may help identify a group of patients with an elevated risk for syncopic episodes which, in turn, may affect the choice of treatment.