MPS 05-01 ORTHOSTATIC HYPOTENSION IS DETERMINED BY ARTERIAL COMPLIANCE IN ELDERLY HYPERTENSIVES

Abstract

Objective: Orthostatic hypotension (OH) is common in the elderly, and is associated with risks of fall, cardiovascular events, and death. We evaluated whether OH was affected by autonomic function, and cardiac structure and function among elderly hypertensives. Design and Method: We evaluated heart rate variability during positional change using the MemCalc system (Reflex meijin, Crosswell) among hypertensive outpatients in the Department of Cardiology. High frequency (HF) was considered to be a marker of para-sympathetic nerve activity, and low frequency (LF) / HF ratio was considered to be a marker of sympathetic nerve activity. We analyzed data of 64 hypertensive patients who were consecutively enrolled into the study with the retrospective review of patients’ medical charts, echocardiography, and blood tests. Results: The mean age was 74.2 ± 1.7, and there were 18 patients (28%) with OH. Patients with OH tend to have smaller systolic volume in echocardiogaphy (57.3 ± 3.0 vs 68.1 ± 2.4, p < 0.05). Presence of OH was related to stroke volume to pulse pressure ratio (SV/PP), a measure of arterial compliance (p < 0.05). However, there was no relationship between OH and sympathetic nerve parameters at rest. Change in LF/HF ratio (ΔLF/HF), a measure of increase in sympathetic nerve activity after standing up, was negatively related to pulse pressure, a measure of arterial stiffness. Coefficient of variation of high frequency (CCVHF), a magnitude of autonomic nerve activity, during standing position was positively related to age and left ventricular diastolic function, measured as E/e’. Conclusions: There were 28% of patients with OH among elderly hypertensives in the geriatric hospital. Presence of OH might be affected by arterial compliance greater than autonomic response, and sympathetic and para- sympathetic nerve activity during positional changes might be associated with cardiovascular aging.