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Daily variation of blood pressure in patients with Cushing's syndrome
1Second Department of Internal Medicine, Tohoku University School of Medicine, Sendai.
Insights
Patients with Cushing's syndrome exhibit abnormal blood pressure rhythms compared to essential hypertension. The hypothalamo-pituitary-adrenal system may regulate normal blood pressure circadian rhythms.
Area of Science:
- Endocrinology
- Cardiovascular Physiology
- Circadian Biology
Background:
- Essential hypertension typically shows a nocturnal dip in blood pressure and heart rate.
- Cushing's syndrome is characterized by excess cortisol, potentially affecting cardiovascular regulation.
Purpose of the Study:
- To compare the circadian blood pressure rhythm in patients with Cushing's syndrome versus essential hypertension.
- To investigate the role of the hypothalamo-pituitary-adrenal axis in blood pressure regulation.
Main Methods:
- Comparative analysis of 24-hour ambulatory blood pressure monitoring.
- Assessment of heart rate patterns in relation to blood pressure.
- Correlation analysis between heart rate and blood pressure parameters.
Main Results:
- Essential hypertension patients demonstrated normal nocturnal blood pressure and heart rate falls with positive HR-BP correlation.
- Cushing's syndrome patients lacked nocturnal blood pressure falls, with some showing a rise, and had HR falls but no significant HR-BP correlation.
- Nocturnal heart rate fall was observed in all Cushing's syndrome patients.
Conclusions:
- The circadian rhythm of blood pressure may be influenced by the hypothalamo-pituitary-adrenal system.
- Disruption of the normal blood pressure circadian rhythm is a feature of Cushing's syndrome.
- Heart rate-blood pressure dynamics differ significantly between Cushing's syndrome and essential hypertension.
Abstract:
The circadian rhythm of blood pressure (BP) was compared between patients with Cushing's syndrome and those with essential hypertension. In patients with essential hypertension, clear nocturnal falls in systolic and diastolic BP and heart rate (HR) were observed, and there was a positive correlation between HR and systolic or diastolic BP. On the other hand, in patients with Cushing's syndrome, there was no nocturnal fall in BP and instead a rise in some cases. In all cases with Cushing's syndrome there was a nocturnal fall in HR, and consequently no significant correlation between HR and BP in these patients. The present results imply that the normal circadian rhythm of blood pressure may be regulated at least in part by the hypothalamo-pituitary-adrenal system.