The Cardiovascular functions are regulated by autonomic nervous system and many physical and hormonal or chemical tests for evaluation of this function have been used.
Auther considered that the head-up tilt test may be simple and easy appropriate method to evaluate the function of baroreflex control of cardiovascular functions. Since there is no report on normal and diseases by this method in Korea, auther studied the changes of cardiovascular function by 70 degree Head-up Tilt test using tilting table in 41 cases of normal adult (age 20-39 year group, 25 cases, age 60-75 year group, 16 cases), 16 cases of untreated mild essential hypertension, 9 cases of treated hypertension with pindolol and clonidine and 4 cases of diabetes mellitus with peripheral neuropathy. The cardiovascular functions studied were heart rate, blood pressure and systolic time interval (PEP, ET, PEP/ET, QS2) at 1, 5,12 minutes after the head-up tilt.
The results were as follows;
1. In normal adult, after 70 degree head-up tilt, the cardiovascular functions were changed since 1 minute and the heart rate increased (average 13/min. after 5 minutes), systolic blood pressure decreased slightly (average 2 mmHg after 5 minutes), diastolic blood pressure increased (average 6 mmHg after 5 minutes), pre-ejection period(PEP) prolonged (average 18 msc increase after 5 minutes), PEP/ET increased (average 0.148 after 5 minutes), ET was shortend (average 52 msc decrease after 5 minutes) and QS2 was shortend (average 32 msc decrease after 5 minutes). The systolic blood pressure change was least noticiable up to 12 minutes after the tilt and the heart rate corrected systolic time intervals showed also similar changes.
2. Comparing the change of above cardiovascular functions in young adult and old adult, the changes of the functions were less marked in old adult than in ybung -adult and the
systolic blood pressure was rather slightly increased at 1 and 5 minute in old adult and de-creased at 12 minute after tilt than control value.
3. In untreated mild essential hypertension, the changes of cardiovascular functions after head-up tilt were less than normal adult which was indicative of reduced baroreflex sensitivity.
4. In treated hypertension and diabetic patients, the changes were less marked than those of untreated hypertension.
5. The test of change of heart rate, blood pressure and systolic time interval by 70 degree head-up tilt test is considered to be a simple appropriate test for the evaluation of sensitivity of the baroreflex.
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