ABNORMAL CIRCADIAN BLOOD-PRESSURE CHANGES IN PATIENTS WITH ACUTE CEREBROVASCULAR DISORDERS

The central neural mechanisms of circadian rhythm are well known in an imal models but less so in humans. In this study we looked for correla tions between abnormalities of circadian rhythm and the sites of strok e, with the aim of identifying the location regulating the circadian r hythm in humans. We investigated the circadian profiles of arterial pr essure in 100 stroke patients by ambulatory blood pressure monitoring within 2 days after their first stroke. Patients also underwent brain computed tomography and measurements of plasma norepinephrine and adre nal hormones. A total of 52 patients (group A) had abnormal patterns o f circadian blood pressure rhythm while 48 patients had normal pattern s (group N). The risk of an abnormal 24-hour blood pressure pattern wa s strongly inversely correlated with the distance between the lesion a nd the hypothalamus. There was a close positive correlation between th e distance from the lesion to the hypothalamus and the circadian indic es of arterial blood pressure (systolic and diastolic pressures) in bo th groups. Abnormal circadian changes in adrenal hormones were found i n 30 of 52 patients in group A, and in nine of 48 patients in group N. Apparently, the circadian rhythm of blood pressure is modulated mainl y by direct neural effects and partly by the hormonal effects of the h ypothalamus and its associated neural pathways. Individualized antihyp ertensive treatment and additional monitoring for possible cardiac eve nts should be performed for those at a high risk of autonomic dysfunct ion.