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PubMed1996

Cardiovascular parameters: sensitivity to detect autonomic dysfunction and influence of age and sex in normal subjects.

In 137 healthy volunteers between 18 and 85 years of age, blood pressure (BP) and heart rate (HR) were measured continuously with the Finapres device during active change of posture (ACP), i.e. standing upright, passive tilt (PT, i.e. head-up tilt), Valsalva manoeuvre (VM), deep breathing (DB), isometric muscle exercise (IME) and a mental arithmetic task (MA). Mean HR activation was attenuated with increasing age in all manoeuvres, but was unrelated to sex. In non-orthostatic challenge procedures like MA and IME mean BP increases were independent of age and sex, despite lower increases in HR in the elderly. This points to a preserved sympathetic efferent activity. Following a forced fall in BP during ACP, PT and VM, the initial responses and maintenance values of BP showed a significant age-related decrease. This finding was strongly related to lower BP values in males compared with females, which became more pronounced with increasing age. Further studies to investigate age-related changes in the activation of the various components of the cardiovascular regulation need to consider the mode of activation of the autonomic nervous system and sex as factors of influence. Normal ranges, and also some new points in time not previously measurable, were calculated for all standard autonomic tests based on the continuous measurement of BP and HR. The minimum length of time necessary to assess the cardiovascular responses during ACP and PT was found to be 60 s. The upper time limits for reaching maximum activation during IME and MA were 3.5 min and 1 min, respectively. Age had a relevant influence on the lower limits of normal of all HR parameters and of some BP measurements during PT, ACP and VM. Sex was found to have no relevant impact on normal ranges. Over 65 years of age the normal values for HR activation during VM and DB hardly exceeded baseline values. The possibility of increasing the sensitivity of detection of autonomic dysfunction by measuring BP continuously must be approached with caution, as sufficient sensitivity was only reached at the lower limits of normal during late phase II of the VM. The initial increase of HR after ACP and the BP values after 60 s standing time proved to be the parameters with the best sensitivity for detecting an affection of the regulation of HR and BP over the whole range of age.

Adolescent↗
PubMed1990

[Autonomic dysfunction in vasculitic neuropathy--special reference to sudomotor function].

We examined autonomic functions in 14 patients with peripheral neuropathy caused by necrotizing vasculitis. These patients consisted of three allergic granulomatous angitis (Churg-Strauss syndrome, AGA), two systemic lupus erythematosus (SLE), two progressive systemic sclerosis (PSS), one mixed connective tissue disease (MCTD), one polyarteritis nodosa (PN) and five nonsystemic vasculitis. All of them were proven to have a vasculitis by sural nerve, muscle or skin biopsy. Sixteen age- and sex-matched healthy volunteers were also examined. Local sweating induced by intradermal injection of pilocarpine and nicotine (a concentration of 10(-4) g/dl, 0.1 ml) was measured with ventilated capsular method on the forearm and lower lateral leg at 23 degrees C of room temperature and 40% of relative humidity. Other autonomic functions including skin temperature at rest and after cold loading (15 degrees C, 6 minutes), variation in the R-R interval of heart beat (CV%), orthostatic hypotension and bladder dysfunction were also monitored. A decrease in sweat rate and recovery rate of skin temperature after cold-loading was seen more frequently in patients with necrotizing vasculitis than normal volunteers. Abnormality in the local sweat response against nicotine and pilocarpine was more frequently present in the involved area of somato-sensory and motor nerves as compared with those in the non-involved area. An occurrence of decrease in recovery rate of skin temperature after cold-loading also well correlated to the region of somato-sensory- and motor involvement. So far other autonomic dysfunction, only one patient had orthostatic hypotension, impotence and bladder dysfunction.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Attenuated Valsalva heart rate response in subjects with smoking history: possible role of autonomic dysfunction.

The effects of smoking habits on autonomic cardiovascular heart rate reflexes were studied in 143 healthy subjects by using the Valsalva manoeuvre and deep breathing tests. Smoking seemed to cause attenuation of the Valsalva heart rate response. This attenuation was present also after adjustment for possible confounding factors including alcohol consumption. Our findings show that in subjects with smoking history there may occur dysfunction in some part of the autonomic reflex arch mediating the Valsalva heart rate response.

Adult↗
PubMed1992

Prevalence of cardiovascular autonomic dysfunction assessed by spectral analysis and standard tests of heart-rate variation in newly diagnosed IDDM patients.

OBJECTIVE: To determine the prevalence of cardiovascular autonomic nerve dysfunction in patients with newly diagnosed insulin-dependent diabetes mellitus (IDDM) compared with healthy nondiabetic subjects. RESEARCH DESIGN AND METHODS: A battery of cardiovascular reflex tests was performed in 130 newly diagnosed IDDM patients aged 12-40 yr at mean blood glucose levels of 7.2 mM after insulin had been administered for 3-39 days. Age-dependent lower limits of normal of these tests were defined at the 2.3 percentile in 120 nondiabetic subjects. Tests of heart-rate variation (HRV) included the coefficient of variation (C.V.) and the low-frequency (LF), midfrequency (MF), and high-frequency (HF) bands of spectral analysis at rest, HRV during deep breathing (C.V., expiratory-inspiratory ratio, and mean circular resultant), Valsalva ratio, and maximum/minimum 30:15 ratio. In addition, spectral analysis on standing, the change in systolic blood pressure to standing, and diastolic blood pressure response to sustained handgrip were determined in 50 patients. RESULTS: A significantly higher percentage of abnormal test responses in the diabetic group compared with the control group was noted for power spectrum in the LF band (7.3 vs. 0.8%, P less than 0.05) and MF band (10.6 vs. 0%, P less than 0.001) at rest and HF band on standing (10.0 vs. 0.9%, P less than 0.05), maximum/minimum 30:15 ratio (25.4 vs. 5.0%, P less than 0.001), and Valsalva ratio (17.5 vs. 4.2%, P less than 0.001). There were no significant differences between both groups in regard to the remaining parameters. Ten (7.7%) diabetic patients but none of the nondiabetic subjects had cardiovascular autonomic neuropathy defined by the strict criterion of abnormal results in more than three of six tests (P less than 0.001). In addition, 12 (9.2%) patients but only 2 (1.7%) control subjects had abnormal results in two of six tests (P less than 0.01). CONCLUSIONS: Cardiovascular autonomic nerve dysfunction is relatively common in newly diagnosed IDDM patients after correction of the initial metabolic imbalance. A combination of tests based on spectral and conventional analysis of HRV appears suitable for detection of early abnormalities in autonomic function in diabetes.

Adolescent↗
PubMed1995

Sympathetic skin response and autonomic dysfunction in diabetes.

Study was conducted on 34 middle aged (35-52 years) diabetics of either sex to compare autonomic function in patients having and not having symptoms of dysautonomia. Fifteen age/sex matched healthy non-diabetic volunteers were control. No symptom of autonomic insufficiency was present in 19 (55.8%) while 15 (43%) diabetics had dysfunction in form of episodic syncope, vertigo, and palpitation, all on postural change. Tests of autonomic functions were restricted to evaluation of salivation, lacrimation, sweating, pilomotor response, reflex erythema and blood pressure changes with valsalva, posture and cold pressor. SSR was elicited using 5 stimuli on programmed Neuropack II and IV model machine. In asymptomatic diabetics, tests of autonomic functions were normal and comparable to controls but SSR was not recordable in 8 (42%). In remaining 11 (58%) asymptomatic diabetics, it was recordable. In 15 subjects who had symptoms of autonomic dysfunction, 6 (40%) had positive test of autonomic function but SSR was normal in only 5 (34%) and not recordable in 10 (66%) subjects. We conclude that SSR can be used as a easy, sensitive and probably early indicator of autonomic functions.

Adult↗
PubMed2000

Is autonomic dysfunction a necessary condition for chronic peptic ulcer formation?

BACKGROUND: The relationship between 1/f fluctuation of the heart rate variability and Helicobacter pylori infection was evaluated, in order to clarify whether autonomic nervous dysfunction is a necessary condition for chronic peptic ulcer formation. METHODS: The subjects were 11 patients with recurrent chronic peptic ulcer and 20 age-matched normal subjects. Holter ECGs were recorded over 24 h, and the 1/f(-x) fluctuation of the heart rate was computed. The 1/f(-x) fluctuation of the heart rate is a novel index of autonomic function that has been shown to reflect a patient's pleasant mood. For 1/f(-x) fluctuation, the slope of the regression line (-x) was determined and cosine fitting of the absolute slope of the regression line over a 24-h period was performed. RESULTS: For the normal group, the absolute slope of the regression line during daytime and night-time were 0.53 +/- 0.16 and 1.05 +/- 0.18, respectively. For the peptic ulcer group, the corresponding values during daytime and night-time were 0.94 +/- 0.15 and 1.84 +/- 0.18, respectively. The mean value of the cosine curve was 0.76 +/- 0.23 in the normal group and 1.12 +/- 0.25 in the peptic ulcer group. Thus, these values were significantly higher for the latter group than for the former group (P<0.05). No statistically significant difference in H. pylori infection between the two groups was observed. CONCLUSIONS: Autonomic nervous dysfunction as well as H. pylori infection appears to be a necessary condition for chronic peptic ulcer formation.

Aged↗
PubMed1993

Cardiovascular autonomic dysfunction in non-insulin-dependent diabetes mellitus and its relation to renal dysfunction.

To investigate the relationship between cardiovascular autonomic neuropathy and nephropathy in patients with non-insulin-dependent diabetes mellitus (NIDDM), 45 patients underwent noninvasive cardiovascular reflex tests, including the Valsalva ratio, the 30:15 ratio and postural changes in systolic blood pressure (delta SBP), along with measurement of creatinine clearance (CCr) and daily protein excretion (DPE). Clinical symptoms in 30 patients were also noted and correlated with the results of the autonomic function tests. Thirty-four normal subjects underwent the same cardiovascular reflex tests and served as controls. The results showed that NIDDM patients had a significantly lower 30:15 ratio than normal subjects. However, no significant difference in either the Valsalva ratio or delta SBP was found between diabetic patients and controls. A positive correlation between the 30:15 ratio and CCr, but not DPE, was noted in diabetics. Although abnormal cardiovascular reflex tests appeared in patients who had no autonomic symptoms, abnormal test results were not parallel with the severity of symptoms. These results show that NIDDM patients have poorer cardiovascular autonomic function which may precede the appearance of autonomic symptoms. The 30:15 ratio was weakly correlated with CCr and this suggests that the incidence of cardiovascular dysfunction increases as the renal functional reserve decreases.

Adult↗
PubMed1987

Correlation of the severity of autonomic dysfunction to cardiovascular reflexes and to plasma noradrenaline levels in Parkinson's disease.

The present study analyses the relation of both the diminished cardiovascular reflexes and the diminished plasma noradrenaline (NA) response to standing to the severity of the autonomic nervous system (ANS) dysfunction in patients with Parkinson's disease (PD). 47 patients with PD were investigated. A clear correlation was established between the duration and the severity of PD (by the Webster rating scale) and the degree of autonomic dysfunction (ANS disability scale). Similarly, a significant negative correlation was found between the diminished cardiovascular reflexes and the clinical severity of the ANS disturbance. Furthermore, a slight correlation was shown between the clinical severity of ANS dysfunction and plasma NA concentrations in response to a standing-up stimulus.

Aged↗
PubMed2003

Cardiovascular autonomic dysfunction in primary Sjögren's syndrome.

OBJECTIVE: To assess the occurrence and clinical significance of a cardiovascular autonomic nervous system dysfunction in primary Sjögren's syndrome (pSS). METHODS: Fifty-one pSS patients participated in this case-control study. Heart rate and blood pressure variability measurements, spontaneous baroreflex sensitivity examinations and cardiovascular reflex tests were performed. RESULTS: The results of the heart rate and blood pressure variability measurements and also the baroreflex sensitivity parameters of the pSS patients peaked in the lowest percentile ranges of a database on 559 healthy control subjects (P < 0.05). In three of the five cardiovascular reflex tests, the frequencies of abnormal results were significantly higher among the patients than among the controls (P < 0.05), and the median autonomic neuropathy score was also elevated (3 vs 0 in the controls; P < 0.0001). CONCLUSION: Signs of an autonomic nervous system dysfunction involving the cardiovascular system can be discerned in the majority of pSS patients.

Adult↗
PubMed1995

Does abnormal QT interval prolongation reflect autonomic dysfunction in diabetic patients? QTc interval measure versus standardized tests in diabetic autonomic neuropathy.

The question as to whether the QTc interval correlates with five cardiovascular tests (deep breathing test, 30/15 ratio test, lying to standing test, cough test, and postural blood pressure test) for the diagnosis of diabetic autonomic neuropathy (DAN) was investigated in 168 (38 Type 1, 130 Type 2) consecutive outpatients (mean age 54.9 +/- 11.2 years). QT interval was measured on an ECG recorded at rest and QTc calculated according to Bazett's formula. The percentage of patients with a QTc greater than 0.440 s was: absent DAN = 11% (n = 7), probable DAN = 7% (n = 4), definite DAN = 23% (n = 12) (p < 0.05), and the mean (+/- SD) QTc values were 0.403 +/- 0.028 s, 0.405 +/- 0.023 s, and 0.421 +/- 0.026 s, respectively. A significant correlation between QTc duration and DAN score of autonomic cardiovascular test results (r = 0.34, p < 0.0001) was observed. The calculated specificity, sensitivity, positive and negative predictive values were 89%, 15%, 70% and 37%, respectively. In conclusion, QTc can be considered as an additional specific test in the assessment of diabetic autonomic neuropathy, but cannot replace the standard battery of cardiovascular tests.

Analysis of Variance↗