[Circadian blood pressure rhythm and its characterization in isolated systolic hypertension (ISH)].

Twenty-four-hour noninvasive ambulatory blood pressure (ABP) was performed in 131 consecutive elderly subjects (61 with isolated systolic hypertension, ISH; 19 with mixed/diastolic hypertension, MDH; 29 with borderline hypertension, BLH; 23 in the normotensive group, NT). It was found that in ISH blood pressure rised during awaking period and fell during sleeping period (P < 0.05); the circadian systolic blood pressure rhythm was similar to ones in MDH, BLH and NT. However, the circadian diastolic blood pressure rhythm was attenuated in ISH. We conclude that circadian blood pressure rhythm alters in ISH, which may be related to the ischemia in organs, especially cerebral ischemia.