Syncope and autonomic cardiovascular dysfunction in Parkinson disease.
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). Twenty-four PD patients were studied, including 10 subjects with syncope/presyncope and 14 con-trols without those symptoms. Ambulatory blood pressure monitoring (ABPM), Holter electrocardiographic monitoring, carotid sinus massage, tilt test, and cardiac scintigraphy with 123I metaiodobenzylguanidine (MIBG) were performed. 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 day-time minimum systolic blood pressure (95% CI: 0.78-0.98; p = 0.007) may be related to the occurrence of syncope/presyncope. The findings suggest an association between syncope/presyncope occurrence and dysfunction of the cardiovascular autonomic system in PD patients. Both 123I 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.