Abstract
We studied sympathetic nervous system dysfunction using the principle of maximum entropy (ME) to perform spectral analysis of systolic blood pressure in patients with diabetes mellitus.
The subjects consisted of 23 patients with diabetes mellitus and 23 healthy controls.Systolic blood pressure was measured using a continuous, noninvasive monitoring system devised by Nihon Colin Co., Ltd., the CBM-2000.Systolic blood pressure(SYS)power spectra were obtained using ME, and areas were measured in two frequency components:a low frequency component (ITC) from 0.02 to 0.15 Hz, and a high frequency component (HFC) from 0.15 to 0.5 Hz.We also compared these results with those of other autonomic nervous function tests and various clinical features of diabetes mellitus.
The low frequency component of systolic blood pressure (SYS-LFC) in patients with diabetes mellitus (2.08 mmHg2) was significantly smaller than that of healthy controls (4.16mmHg2). There was, however, no significant difference in SYS-HFC between patients with diabetes mellitus (0.97mmHg2) and healthy controls (1.21mmHg2). The SYS-LFCs in diabetic patients with disturbed Valsalva overshoot, a positive cold pressor test and/or orthostatic hypotension were significantly smaller than in those who did not have these features. In patients with delay of peripheral nerve conduction velocity, SYS-LFC was significantly smaller than that in patients without this delay.
In diabetics, measurements of the low frequency component of systolic blood pressure using spectral analysis correlated with sympathetic nervous system function and may therefore be useful for evaluating sympathetic nervous system dysfunction.
