Biomedical subjects

C Broadbridge

Publications and source records attributed to C Broadbridge.

4 recordsLinked to original sources

PubMed2001

Heart rate variability measurement in diabetic neuropathy: review of methods.

Heart rate variability (HRV) is an important tool to analyze the autonomic function. It therefore has a special interest for early detection and ensuing treatment of autonomic neuropathy in diabetic patients. The aim of this work is to present a brief historical review of HRV, as well as a technical review of the most common methods to measure it. In this work is presented a system that performs three measurements of HRV. An overview of methodologies developed to quantify HRV is presented; this technical review covers the most common time and frequency domain techniques, for short and long periods of time, with comments about clinical utility of these tests. A system performing three standard tests of HRV, Anscore Health Management System, is presented. This system performs metronomic breathing (MT), the Valsalva Test (VT), and the Stand Test (ST). A normal range study with 212 healthy subjects in three centers (ages 20-80 years, with even age distribution, and even male and female distribution) was conducted. A subset of 45 subjects from the total number of subjects was selected for the reproducibility study, consisting of three measurements of each test. The normal range study showed a decrease in all the ratios with age and, for the Valsalva test, a difference among genders; 5th percentiles were calculated. The reproducibility study results, expressed as mean CV%, were 4.30% for the MT, 6.26% for the VT, and 6.66% for the ST. HRV is the most reliable measurement of autonomic function; when controlled maneuvers like MT, VT, and ST are performed, high reproducibility is obtained, with results comparable to that observed for nerve conduction studies. Such reproducibility makes autonomic function testing more feasible as a test component in multicenter studies of different neurological disorders.

Adult↗

PubMed1997

Cardiovascular autonomic tests in diabetic patients with gastroparesis.

The aim of this report was to study the cardiovascular autonomic tests in the evaluation of diabetic patients with gastroparesis. Forty diabetic subjects were divided into two groups: one group with gastroparesis (GP, n = 20) and another group paired by age and duration of diabetes without any complaint of autonomic neuropathy (DC, n = 20). They were evaluated clinically and submitted to a battery of five cardiovascular autonomic tests. The presence and severity of autonomic neuropathy were defined according to the number of normal cardiovascular tests. Each test had a score: zero (normal), one (borderline) and two (abnormal). The GP group showed a higher abnormal total score in the cardiovascular autonomic test than the group without any complaint (6.6 +/- 3.0 vs. 2.7 +/- 1.4, p < 0.01). These data suggest that diabetic with gastroparesis presents more abnormal cardiovascular autonomic tests than diabetic without autonomic neuropathy and these tests should be included in the evaluation of diabetic patients with gastroparesis.

Adult↗

PubMed1991

Spectral analysis of heart rate in diabetic autonomic neuropathy. A comparison with standard tests of autonomic function.

Power spectral analysis of the heart rate was compared with standard tests of autonomic function performed on 15 insulin-dependent diabetic patients with symptoms of autonomic dysfunction. The high-frequency power, low-frequency power, and total power of the heart rate power spectrum measured in the supine position--possible measures of parasympathetic nervous system function--were significant predictors of the expiratory-inspiratory ratio, the beat-to-beat heart rate difference on deep respiration, the standard deviation of the resting heart rate, the 30:15 ratio, and the Valsalva ratio. The change in low-frequency power on moving from the supine to upright position, a possible measure of sympathetic nervous system function, was a modest predictor of the systolic and diastolic blood pressure fall in response to postural change, but a poor predictor of the blood pressure response to isometric exercise and a cold stimulus. This study supports the role of heart rate power spectral analysis as a clinical test of autonomic function in patients with known or suspected autonomic failure.

Adult↗

PubMed1990

Autonomic function and human immunodeficiency virus infection.

We compared autonomic function in 26 patients infected by the human immunodeficiency virus (HIV) (18 AIDS and 8 ARC) to 22 controls. A significant decline in autonomic function was present across groups. Autonomic dysfunction correlated strongly with signs of HIV-associated nervous system disease. We observed significant differences across groups in tests of heart rate variation (expiratory-inspiratory ratio, maximum minus minimum heart rate difference, and mean square successive difference), the mean arterial blood pressure fall to tilting, and the blood pressure response to isometric exercise. A trend of declining autonomic function from controls to AIDS was present in the 30:15 ratio, the Valsalva ration, the systolic blood pressure fall to standing and tilt, and the cold pressor test. We did not observe any correlation between autonomic dysfunction and individual neurologic signs, prior therapeutic agents, and concurrent HIV-associated inflammatory or neoplastic processes. This study provides support for the presence of autonomic dysfunction in association with HIV infection. Autonomic dysfunction occurs more frequently and with greater severity in patients with AIDS; however, it may be present in the early stages of HIV infection and appears to progress during the illness.

AIDS-Related Complex↗