Ambulatory blood pressure monitoring and cardiovascular function tests in multiple system atrophy

Cardiovascular tests (CT) of autonomic function and non-invasive ambulatory blood pressure (BP) and heart rate (HR) monitoring were performed in 17 patients with multiple system atrophy (MSA) (mean age 61 ± 9 years) and in 12 healthy subjects matched for sex and age. CT showed severe autonomic dysfunction with orthostatic hypotension (OH) in eight patients with MSA (47%) (Group I). The remaining nine out of the 17 patients didn't show BP abnormalities during CT but an impaired HR reflex response was found (Group It). BP monitoring showed a reversed circadian BP rhythm in Group I with higher night-time than daytime values, a blunted circadian BP pattern in Group II and a normal day-night BP reduction in controls. Day-night HR reduction was poor in Group II and absent in Group I. Post-prandial hypotension was evaluated after a standard meal. In Group I systolic/diastolic BP fell within 30 minutes after meal (from 135 ± 16/89 ± 13 to 118 ± 17/73 ± 12 mmHg; p <0.05) and after two hours had not returned to basal levels. In Group II a reduction of only systolic BP was found within 45 minutes after meal and persisted for one hour. OH clinically identifies a subgroup of MSA patients with a more severe BP dysregulation characterized by severe post-prandial hypotension and reversed circadian BP rhythm. CT and ambulatory BP monitoring are useful tools in identifying early stage of cardiovascular autonomic impairment.