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PubMed2002

Evoked cavernous activity.

PURPOSE: Corpus cavernosum electromyography has been widely done to evaluate autonomic dysfunction in patients with erectile dysfunction. We assessed the value of corpus cavernosum electromyography, evoked cavernous activity and penile sympathetic skin responses for their accuracy in determining autonomic involvement in cases of erectile dysfunction. MATERIALS AND METHOD: We evaluated 75 men with erectile dysfunction by corpus cavernosum electromyography, evoked cavernous activity and penile sympathetic skin response tests at our neurourology laboratory. The etiology of dysfunction was vascular, neurogenic, psychogenic or mixed based on a detailed medical and sexual history, physical examination, electrophysiological and laboratory studies, penile color Doppler ultrasonography, and cavernosography and/or cavernosometry. Autonomic involvement was clinically assessed by systemic findings, such as orthostatic hypotension, impaired gastrointestinal motility, sinus dysrhythmia and secretomotor changes. A concentric electromyography needle placed in the right cavernous body was used to record corpus cavernosum electromyography and evoked cavernous activity. The right median nerve was stimulated electrically with 13 to 16 mA. to determine evoked cavernous activity and the penile sympathetic skin response. The latter response was recorded with silver disc electrodes placed on the left cavernous body. All tests were performed using an electromyography/evoked potential machine. We determined the relationships among corpus cavernosum electromyography, evoked cavernous activity and penile sympathetic skin response tests in respect to etiological factors. RESULTS: The 56 patients with normal corpus cavernosum electromyography activity had also evoked cavernous activity and a penile sympathetic skin response except for 1 with no penile sympathetic skin response but evoked cavernous activity. None of these patients had autonomic neuropathy. Of the 19 patients without corpus cavernosum electromyography activity 11 had evoked cavernous activity, including 10 with no autonomic neuropathy. The remaining 8 patients had no evoked cavernous activity, of whom 7 had autonomic neuropathy. A penile sympathetic skin response was recorded in 18 men with absent corpus cavernosum electromyography. CONCLUSIONS: Due to false-negative results on corpus cavernosum electromyography and penile sympathetic skin response testing evoked cavernous activity seems more reliable for determining autonomic involvement in the pathophysiology of erectile dysfunction.

Adult↗
PubMed1991

Posttraumatic hyperthermia: a possible result of fronto-diencephalic dysfunction.

A patient with traumatic bifrontal hemorrhagic lesions developed hyperthermia associated with autonomic dysfunction shortly after admission. This case illustrates that posttraumatic hyperthermia may also occur at a markedly less disturbed baseline neurological level, possibly secondary to disruption of fronto-diencephalic pathways.

Adult↗
PubMed2000

Delayed gastric emptying in human immunodeficiency virus infection: correlation with symptoms, autonomic function, and intestinal motility.

Gastric emptying may be delayed in HIV infection. We aimed to characterize the pattern of gastric emptying in HIV seropositive subjects and correlate the findings with symptoms, as well as to identify possible etiological factors. Solid gastric emptying was measured using scintigraphy in 54 HIV seropositive subjects and 12 HIV seronegative controls. Gastrointestinal symptoms were evaluated using a standardized numerical score, and autonomic function was assessed using spectral analysis of heart rate variability. Fasting and postprandial duodenojejunal activity was recorded using strain gauge manometry catheters. Gastric emptying rate, but not lag phase, was significantly delayed in HIV-infected subjects, particularly those with enteric infections and more advanced disease. Delayed gastric emptying did not correlate with symptoms, autonomic dysfunction, or small intestinal motility. In conclusion, abnormalities found in autonomic function and gastric emptying in HIV infection are multifactorial in nature. The contribution of upper gastrointestinal motor dysfunction to gastric symptoms in such individuals is unclear.

Adult↗
PubMedDate not supplied

Clinical studies of autonomic function and dysfunction.

A discussion of progressive autonomic failure in man. This is one of the few neurological diseases disrupting cardiovascular function. Both central and peripheral pathways are involved. Means of diagnosing defects in autonomic reactions are described. Abnormalities in responses due to multiple system atrophy (MSA) are discussed most extensively.

Afferent Pathways↗
PubMed2005

Cardiac autonomic modulation in hypertensive patients with Chagas' disease.

BACKGROUND: Arterial hypertension and Chagas' disease are prevalent pathologies in Latin America. It has been demonstrated that each one of them may cause cardiac autonomic dysfunction. This study aimed to investigate the pattern of cardiac autonomic modulation in chagasic-hypertensive patients. METHODS: Subjects (n=120) without left ventricular dysfunction were distributed in four groups: healthy control (n=30); hypertensive (n=30); chagasic (n=30) and chagasic-hypertensive (n=30). Patients were evaluated by autoregressive spectral analysis of heart rate variability in three different conditions: baseline, cold face and passive tilt tests. Power spectral densities in low (0.04-0.15 Hz) and high (0.15-0.50 Hz) frequency bands were estimated in both absolute and normalized units. RESULTS: Baseline median values (percentile 25 to percentile 75) of mean arterial pressure (in mmHg) were 93.3 (85.0-96.7), 116.7 (*, #) (110.0-129.2), 86.7 (83.3-92.5) and 106.7 (*, #) (106.7-110.0) for healthy control, hypertensive, chagasic and chagasic-hypertensive patients, respectively (*p<0.05 versus healthy control, #p<0.05 against chagasic group). Heart rate at rest did not differ among groups. Regarding to spectral parameters in baseline conditions, the absolute power of high frequency component of heart rate variability of the chagasic-hypertensive group was significantly lower than that found in healthy control and hypertensive patients. There were no differences in spectral parameters responses during cold face test. After passive tilt test, however, decreases in high frequency oscillations and increases in sympathovagal balance (low and high frequency ratio) were significantly lower in hypertensive, chagasic and chagasic-hypertensive patients as compared with healthy control. CONCLUSIONS: These data indicate that chagasic-hypertensive patients presented an impairment of cardiac parasympathetic modulation at baseline conditions as well as in response to passive orthostatic stress.

Adult↗
PubMed1984

Insulin treatment prevents vascular dysfunction in early juvenile alloxan-induced diabetes mellitus.

Microvascular pathology and sympathetic autonomic dysfunction have been described early in alloxan-induced diabetic juvenile rats. To determine the longitudinal development of these changes and whether insulin treatment can alter them, vascular and sympathetic function were studied in alloxan-induced (42.5 mg/kg) juvenile diabetic rats and saline-treated controls. The rats were examined 1 and 14 days after induction of diabetes. An insulin-treated group was studied with the 14-day group. Hindquarter perfusion with an artificial solution at constant flow/100 g hindquarter wt was used. After 14 days of diabetes mellitus, the diabetic group showed a significantly depressed response to central ischemia (P less than 0.001), maximal vasoconstriction (P less than 0.02), and maximal dilation (P less than 0.001) compared with both the control and insulin-treated group. The threshold response to norepinephrine did not differ. After 1 day of glucose elevation no differences were present between the control and diabetic animals during any of the testing procedures. These results suggest that severe vascular dysfunction develops early in juvenile-onset alloxan diabetes and that it can be prevented with insulin treatment.

Animals↗
PubMedDate not supplied

Autonomic nervous system dysfunction in chronic uraemics on haemodialysis.

A battery of cardiovascular reflex tests were performed in 35 patients with chronic renal failure on intermittent haemodialysis. An impairment of parasympathetic control was found isolated (14%) or combined with a damage of sympathetic control of cardiovascular system (26%). Moreover, maximum conduction velocity along sensory and motor fibres of posterior tibial nerve was measured in 21 patients. Autonomic dysfunction and somatic neuropathy did not appear strictly related.

Adult↗
PubMed2005

Cross-spectral analysis of cardiovascular variables in supine diabetic patients.

Cardiovascular autonomic neuropathy in diabetes is associated with a high risk of mortality, which makes its early identification clinically important. An easy method for identification of subjects with autonomic dysfunction would be of clinical benefit. We evaluated the autonomic function in 28 diabetic patients and 21 control subjects recording 12 min time series of heart period (RR) and systolic arterial pressure (SAP, Finapres) during supine rest and 60 degrees head-up tilt. The power of the high (respiratory) and low (LF approximately 0.1 Hz) frequency oscillations was quantified by spectral analysis. The central frequency of the LF oscillations (LF_freq), phase shift, and the transfer function gain between RR interval and SAP fluctuations were provided by cross-spectral analysis, and measured at the point of maximal coherence. In the supine position 15 patients (LF-) displayed atypical LF variability with the LF_freq being shifted towards lower frequencies (about 0.06 Hz). They also showed larger phase angle, lower values or even absence of coherence and smaller transfer function gain between RR and SAP fluctuations. 13 patients (LF+) and the controls showed the LF_freq around 0.1 Hz, higher coherence and transfer function gain values. The orthostatic maneuver induced the expected changes in the spectral parameters (increase in the LF components of both RR and SAP and decrease in the HF variability of RR) into the LF+ patients and all the control subjects and abnormal response in the other 15 LF-patients. These findings indicate that diabetic subjects with uncharacteristic response to the orthostatic test present abnormal LF variability already in the supine position. Crossspectral parameters while supine may be used for the identification of these subjects.

Adult↗
PubMed1998

Abnormalities of the QT interval in primary disorders of autonomic failure.

BACKGROUND: Experimental evidence shows that activation of the autonomic nervous system influences ventricular repolarization and, therefore, the QT interval on the ECG. To test the hypothesis that the QT interval is abnormal in autonomic dysfunction, we examined ECGs in patients with severe primary autonomic failure and in patients with congenital dopamine beta-hydroxylase (DbetaH) deficiency who are unable to synthesize norepinephrine and epinephrine. SUBJECTS AND METHODS: Maximal QT and rate-corrected QT (QTc) intervals and adjusted QTc dispersion [(maximal QTc - minimum QTc on 12 lead ECG)/square root of the number of leads measured] were determined in blinded fashion from ECGs of 67 patients with primary autonomic failure (36 patients with multiple system atrophy [MSA], and 31 patients with pure autonomic failure [PAF]) and 17 age- and sex-matched healthy controls. ECGs of 5 patients with congenital DbetaH deficiency and 6 age- and sex-matched controls were also analyzed. RESULTS: Patients with MSA and PAF had significantly prolonged maximum QTc intervals (492+/-58 ms(1/2) and 502+/-61 ms(1/2) [mean +/- SD]), respectively, compared with controls (450+/-18 ms(1/2), P < .05 and P < .01, respectively). A similar but not significant trend was observed for QT. QTc dispersion was also increased in MSA (40+/-20 ms(1/2), P < .05 vs controls) and PAF patients (32+/-19 ms(1/2), NS) compared with controls (21+/-5 ms(1/2)). In contrast, patients with congenital DbetaH deficiency did not have significantly different RR, QT, QTc intervals, or QTc dispersion when compared with controls. CONCLUSIONS: Patients with primary autonomic failure who have combined parasympathetic and sympathetic failure have abnormally prolonged QT interval and increased QT dispersion. However, QT interval in patients with congenital DbetaH deficiency was not significantly different from controls. It is possible, therefore, that QT abnormalities in patients with primary autonomic failure are not solely caused by lesions of the sympathetic nervous system, and that the parasympathetic nervous system is likely to have a modulatory role in ventricular repolarization.

Aged↗
PubMed1991

Aspects of autonomic neurophysiology in diabetic polyneuropathy: a brief review.

The autonomic nervous system is a very diverse system, governing many organs according to endogenous and environmental demands. Consequently autonomic dysfunction in diabetic polyneuropathy is many faceted. Assessment of autonomic nerve function, by testing the reflex responses of autonomic effector organs, should preferably take this differentiation into account. Microneurography allows direct study of the normal and disturbed physiology of two subdivisions of the sympathetic nervous system: signals in muscle nerve fascicles involved in cardiovascular homeostasis, and impulses in skin nerve fascicles involved in body thermoregulation. Observations made with this research tool emphasize the functional differentiation of the autonomic nervous system, and the technique can be used to elucidate pathophysiological mechanisms in disorders such as diabetic polyneuropathy.

Autonomic Nervous System↗
PubMed2006

Power spectral analysis of heart rate variability in HIV-infected and AIDS patients.

BACKGROUND: In HIV-infected patients the risks for cardiovascular disease are multifactorial. Autonomic dysfunction has been detected in the early phase of HIV infection as well as in AIDS patients with advanced cardiomyopathy. METHODS: Forty AIDS patients receiving highly active antiretroviral therapy (HAART), 40 HIV+ naïve of HAART, and 40 control subjects were studied. Computerized analysis of heart rate variability was performed using an analog to digital converter. R-R intervals were obtained from a standard ECG, recorded in DII lead in supine rest and after the cold-face and tilt tests. The series of R-R intervals were assessed in time and frequency domains using an autoregressive algorithm. RESULTS: There was no difference regarding to mean values of R-R intervals and variance in baseline. The normalized power of the low-frequency (LF) component and the low-frequency/high-frequency (HF) ratio (LF/HF) was significantly decreased in the HIV group. Responses of normalized HF and LF/HF ratio during the cold-face test were significantly decreased in the HIV group, as compared to the control. During the tilt test, a higher augmentation of normalized LF and the LF/HF ratio was observed in the HIV group compared with the control. The AIDS group was similar to the control in baseline and after cold-face and tilt tests. CONCLUSION: The HIV group presented in baseline conditions, a shift of cardiac sympathovagal balance, an exacerbated response of the LF component during the tilt test, and an ineffective cardiac vagal response to the cold-face test suggesting sympathetic and parasympathetic dysfunction. AIDS patients receiving HAART did not present these autonomic alterations.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Recovery of respiratory sinus arrhythmia in detoxified alcoholic subjects.

Although most alcoholic subjects show little autonomic dysfunction, severe alcoholic subjects may have pathological changes in autonomic nerves. We asked if respiratory sinus arrhythmia amplitude (RSA), an index of vagal cardiac control, is decreased in alcoholism and, if so, whether the decrease is reversed with abstinence. RSA was assessed in 17 normotensive alcoholic subjects (A) at 1, 4, 12, and 24 wk of abstinence after detoxification and at similar intervals in 17 controls (C) matched for age, race, and gender. Subjects were studied in both supine and seated positions while breathing in a prescribed deep (> 50% vital capacity) and slow (5-7/min) pattern. Mean heart rate (HR) was determined over 30 s from the electrocardiogram; RSA (the difference between maximum and minimum instantaneous HRs after inspiratory onset) was determined from 10 consecutive breaths. In C, both HR (supine: 61.5 +/- 2.2 beats/min; seated: 71.3 +/- 1.7 beats/min; P < 0.002) and RSA (supine: 22.5 +/- 1.0 beats/min; seated: 28.4 +/- 1.4 beats/min; P < 0.003) were higher when seated than when supine, but neither HR nor RSA varied over 24 wk. At week 1 of abstinence, HRs for A were higher than those for C (supine: 74.2 +/- 2.3 beats/min, P < 0.001; seated: 83.2 +/- 2.7 beats/min, P < 0.003), but by week 24, both seated and supine values returned to control levels. RSA in A at week 1, was only one-half that of C (supine: 11.1 +/- 1.4 beats/min, P < 0.001; seated: 14.7 +/- 1.9 beats/min, P < 0.001) and independent of body position.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2000

Left ventricular mass predicted by a single reading of ambulatory blood pressure in essential hypertension.

The spectral power of heart rate variability has been shown to be negatively correlated with left ventricular mass (LVM), suggesting the contribution of left ventricular hypertrophy to autonomic dysfunction in essential hypertension. However, a simultaneous assessment of autonomic function and ambulatory blood pressure in relation to LVM has not been carried out. The objective of the present study was to elucidate the synergistic effects of ambulatory blood pressure and autonomic nerve activity on the heart. We enrolled 25 ambulant patients with untreated essential hypertension (9 men and 16 women; mean age 50.6 +/- 2.0 years). The ambulatory blood pressure and heart rate variability were simultaneously monitored every 30 min for 24 h. The spectral power of high-frequency (HF: 0.15 to 0.4 Hz) and low-frequency (LF: 0.05 to 0.15 Hz) bands were measured, and the ratio of LF to HF (LF/HF) was calculated. LF/HF and HF were used as indexes of sympathetic and parasympathetic activities, respectively. LVM was determined by echocardiography. Both the average daytime and nighttime systolic ambulatory blood pressures significantly correlated with the LVM index (r= 0.644, p< 0.001; and r= 0.428, p< 0.05; respectively), although there was no such correlation with the clinic blood pressures. In contrast, a single reading of ambulatory systolic blood pressure measured when LF/HF reached a maximum value was significantly correlated with the LVM index independently of age and sex (partial r= 0.484, p< 0.05). These results suggest that the ambulatory systolic blood pressure during increases in the activity of the sympathetic nervous system is able to infer LVM in essential hypertension.

Blood Pressure↗
PubMedDate not supplied

Lowered sympathetic reactivity in patients with non-bleeding duodenal ulcers.

BACKGROUND: Autonomic dysfunction has been associated with duodenal ulcer. We assessed autonomic reactivity in patients with duodenal ulcer. METHODS: Ten patients with non-bleeding active duodenal ulcers and ten age- and sex-matched healthy subjects were investigated for parasympathetic reactivity (heart rate response to deep breathing, Valsalva maneuver and head-up tilt test) and sympathetic reactivity (blood pressure response to hand grip, head-up tilt and cold pressor test). Anxiety status was measured by evaluating responses to a questionnaire. RESULTS: The duodenal ulcer patients showed normal parasympathetic reactivity, lowered sympathetic reactivity and high anxiety score. When compared to control subjects, they had significantly lower diastolic blood pressure change in response to hand grip (median [range]; difference in values 12 [4-16] mmHg vs 16 [10-22] mmHg) and head up tilt (1 [-6-4] vs 6 [2-10] mmHg). CONCLUSIONS: Patients with duodenal ulcer have lowered sympathetic reactivity; this may be involved in causation by decreasing mucosal protection.

Adult↗
PubMed1990

The mechanism of symptomatic postural hypotension in the elderly.

To study the mechanism of symptomatic postural hypotension in the elderly, we collected 11 such patients to further divide them into group 1 with central nervous system (CNS) involvement and group 2 without CNS involvement. Group 1 was the so-called Shy-Drager syndrome, and group 2 was the elderly postural hypotension not secondary to the medications or other systemic diseases. All patients had various degree of autonomic dysfunction and heterogenous defects in the reflex arc of autonomic nervous system (ANS). Both groups also had normal plasma volume but reduced blood volume. Patients in group 1 had normal level of plasma norepinephrine in recumbent posture, but failed to increase normally after standing (p less than 0.05, as compared the percentage rising with that of the controls). Patients in group 2 had near normal level of plasma norepinephrine in recumbent posture and could rise normally after standing. They also had normal level of plasma epinephrine in recumbent posture, but failed to rise normally after standing (p less than 0.05 as compared with the controls). These findings suggested that impaired responsiveness of end organs as blood vessels and adrenal medulla is one of the major causes responsible for the symptomatic postural hypotension in the elderly without CNS involvement.

Age Factors↗
PubMed1996

Disorders affecting autonomic function in parkinsonian patients.

This chapter deals with certain aspects of autonomic dysfunction in parkinsonian patients. It provides a classification of autonomic disorders and a brief description of autonomic manifestations. An outline of autonomic investigations, including those to diagnose the Shy-Drager syndrome (multiple system atrophy), is provided. It concludes with comments on terminology and on whether the parkinsonian syndromes with autonomic failure comprise single or multiple entities.

Autonomic Nervous System Diseases↗
PubMed1994

Arrhythmias and the autonomic nervous system.

This review discusses the current evidence relating to the prevalence and significance of markers of electrical instability and of autonomic dysfunction in patients who have suffered acute myocardial infarction in light of recent studies performed in patients given thrombolytic therapy during the acute phase. Among markers of electrical instability, emphasis is placed upon the frequency of ventricular arrhythmias during Holter monitoring, the presence of late potentials at signal averaging and the inducibility of ventricular tachycardia during programmed electrical stimulation. Among indices of autonomic nervous system dysfunction, data relating to heart rate variability and baroreflex sensitivity are summarized and discussed.

Arrhythmias, Cardiac↗