Contribution of cardiovascular hypersensitivity to orthostatic hypertension and the extreme dipper phenomenon

We report the case of a 68-yr-old woman who, upon standing, experienced diz ziness in association with increased blood pressure (BP) and heart rate (HR ). We made a diagnosis of orthostatic hypertension and examined the BP resp onse to postural change using the head-up tilt test. Positional change resu lted in a 20-mmHg increase in systolic BP and a 15-bpm increase in HR. A 24 -h ambulatory BP recording showed daytime hypertension that decreased at ni ght, along with a nocturnal decrease in HR. Based on these post-diagnostic results, the patient was rediagnosed as an extreme dipper with silent lacun ar infarction as the only complication of orthostatic hypertension. We sugg est that, in our patient, the mechanism of orthostatic hypertension was hyp ersensitivity of cardiovascular responsiveness to endogenous vasoconstricto rs. This was evidenced by increased pressure sensitivity to isoproterenol a s well as phenylephrine. We thus selected carvedilol, a beta-blocker with s light alpha-blocking action, and were more effective in abolishing the hype rtension. (Hypertens Res 2000; 23: 119-123).