Primary dysautonomia in the elderly: diagnostic value of the circadian variations in blood pressure.

Purpose.-Ambulatory blood pressure monitoring allows characterization of th e circadian variations in blood pressure. Methods. - In order to investigate the diagnostic value of circadian variat ions in blood pressure in the elderly, II patients with autonomic failure a nd 11 central subjects paired on age, blood pressure level and daily life a ctivity range were studied. Results. - Periodic postural disorders, positive response to passive tilt-t est and alpha denervation supersensitivity to noradrenaline were found in a ll patients with autonomic failure. In control subjects, blood pressure lev els assessed by ambulatory monitoring were lower at night. Conversely: circ adian variations in blood pressure were higher at night and lower in the mo rning in patients with autonomic failure. The nadir of blood pressure measu rements was related with the reported time of peak incidence of orthostatic symptoms. Conclusion. - Ambulatory 24-hour blood pressure monitoring may therefore be of value in the diagnosis and management of patients with autonomic failur e. (C) 1999 Elsevier, Paris.