Beat-to-Beat Blood Pressure Response in Asymptomatic IDDM Subjects

Abstract

Nine insulin-dependent diabetic (IDDM) patients (aged 25-37 yr) with no symptoms of autonomic neuropathy and 15 healthy control subjects (aged 26-39 yr) were studied at rest and during tests of Valsalva maneuver, deep breathing, cold pressor, and postural change from sitting to standing. Continuous (beat-to-beat) measures were taken of heart rate, systolic blood pressure, diastolic blood pressure, and skin conductance. The diabetic patients were differentiated from the control group by the following: less variability in diastolic blood pressure during deep breathing, failure to exhibit diastolic blood pressure decreases during recovery from a cold pressor stimulus, a flatter blood pressure response pattern when changing from sitting to standing, and a smaller standing ratio (maximum/minimum) for R-R interval. Among the patients, age was negatively correlated with systolic and diastolic standing ratios and diastolic blood pressure variability during deep breathing. By use of the tracking cuff, a method of continuously recording blood pressure noninvasively, we have been able to assess subtle blood pressure changes, thereby revealing signs of sympathetic dysfunction in a group of relatively young diabetic patients with no symptoms of neuropathy. The tracking-cuff method of recording blood pressure has potential in further research on autonomic functioning in diabetic patients.

Acute Autonomic Responses to Postural Change, Valsalva Maneuver, and Paced Breathing in Older Type II Diabetic Men

“…In these relatively asymptomatic patients, the exaggerated DBP response and relationship between Valsalva HR variability and DBP change was only evident by a careful analysis of the first minute of standing, before any measurement might be taken using traditional discrete cuff inflation techniques. Our results differ somewhat from a previous study, which found a smaller fall in DBP immediately after standing for younger Type I diabetic patients compared with age‐matched controls 14 . Since the present sample is different in terms of both age and type of diabetes, it is hard to draw firm conclusions regarding mechanisms for these opposite findings.…”

“…This system provides continuous beat‐by‐beat monitoring of systolic and diastolic blood pressure and heart rate and, therefore, allows for assessment of both the acute (within the first minute) and tonic adjustments following standing. In a recent study of Type I diabetic patients, we found an altered blood pressure response to standing compared with controls 14 . The diabetic group did not show a hypotensive response but instead a smaller fall in systolic and diastolic pressure immediately after standing, indicative of subtle sympathetic neuropathy.…”

“…More severe autonomic neuropathy leads to symptomatic orthostatism, hypoglycemic unawareness, and a variety of other sympathetic and parasympathetic dysfunctions 13 . Evidence in Type I and Type II diabetic patients indicates that even in the early stages of autonomic neuropathy, some abnormalities of sympathetic function may be detectable 14–17 . Pfeifer et al 17 have shown decreased sympathetic and parasympathetic function in recently diagnosed (ages 30 to 66) Type II diabetics, even with age adjustment.…”

“…A promising new technology for analysis of the cardiovascular response to short term stimuli is the tracking cuff blood pressure system 14,18–21 . This system provides continuous beat‐by‐beat monitoring of systolic and diastolic blood pressure and heart rate and, therefore, allows for assessment of both the acute (within the first minute) and tonic adjustments following standing.…”

Autonomic Neuropathy Predicts Deterioration in Glomerular Filtration Rate in Patients With IDDM

“…Although parasympathetic neuropathy might be a DIABETES CARE, VOLUME 16, NUMBER 5, MAY 1993 primary event (20), as also indicated by the increased heart rate in our patients with autonomic neuropathy, recent studies have shown that sympathetic neuropathy may develop not only in parallel with (21) but also before parasympathetic neuropathy (22,23). The indexes of autonomic neuropathy in this study evaluated parasympathetic as well as sympathetic neuropathy.…”