Impaired Autonomic Nervous System Function Research Articles

The autonomic and nociceptive response to acute experimental stress is impaired in people with knee osteoarthritis: A preliminary study

ObjectiveAlterations in autonomic function are evident in some chronic pain conditions but have not been thoroughly examined in people with osteoarthritis (OA). The study aimed to examine resting autonomic nervous system (ANS) function in people with knee OA, and the response of the autonomic and nociceptive systems to acute stress. MethodsA preliminary cross-sectional study was undertaken involving people with knee OA (n = 14), fibromyalgia (n = 13), and pain-free controls (n = 15). The sympathetic and parasympathetic components of the ANS were assessed through measures of pre-ejection period (PEP), skin conductance level (SCL), and high frequency heart rate variability (HF HRV). The nociceptive system was assessed through pain ratings associated with a tonic heat pain stimulus. In separate sessions, ANS and heat pain measures were assessed at rest and in response to nociceptive and mental arithmetic stressors. ResultsThe knee OA group showed reduced HF HRV at rest and reduced modulation in response to stress. Resting PEP and SCL were normal in the knee OA group but PEP modulation was impaired in both chronic pain groups during nociceptive stress. The expected reduction in tonic heat pain ratings in response to stress was lacking in the knee OA and FM groups. ConclusionPreliminary evidence shows impaired parasympathetic nervous system function at rest and in response to nociceptive and mental stress in people with knee OA, with some evidence of altered sympathetic nervous system function. Impaired ANS function could contribute to ongoing pain experienced, and interventions that target ANS function could be beneficial.

Autonomic Dysfunction in Neonates with Hypoxic Ischemic Encephalopathy Undergoing Therapeutic Hypothermia Impairs Physiological Responses to Routine Care Events

To evaluate whether infants with hypoxic-ischemic encephalopathy and evidence of autonomic dysfunction have aberrant physiological responses to care events that could contribute to evolving brain injury. Continuous tracings of heart rate (HR), blood pressure (BP), cerebral near infrared spectroscopy, and video electroencephalogram data were recorded from newborn infants with hypoxic-ischemic encephalopathy who were treated with hypothermia. Videos between 16 and 24 hours of age identified 99 distinct care events, including stimulating events (diaper changes, painful procedures), and vagal stimuli (endotracheal tube manipulations, pupil examinations). Pre-event HR variability was used to stratify patients into groups with impaired versus intact autonomic nervous system (ANS) function. Postevent physiological responses were compared between groups with the nearest mean classification approach. Infants with intact ANS had increases in HR/BP after stimulating events, whereas those with impaired ANS showed no change or decreased HR/BP. With vagal stimuli, the HR decreased in infants with intact ANS but changed minimally in those with impaired ANS. A pupil examination in infants with an intact ANS led to a stable or increased BP, whereas the BP decreased in the group with an impaired ANS. Near infrared spectroscopy measures of cerebral blood flow/blood volume increased after diaper changes in infants with an impaired ANS, but were stable or decreased in those with an intact ANS. HR variability metrics identified infants with impaired ANS function at risk for maladaptive responses to care events. These data support the potential use of HR variability as a real-time, continuous physiological biomarker to guide neuroprotective care in high-risk newborns.

Cardiovascular autonomic dysfunction in patients with idiopathic diabetes insipidus.

Central diabetes insipidus (DI) is a rare disease characterized by the excretion of excessive volumes of dilute urine due to reduced levels of the antidiuretic hormone arginine vasopressin (AVP), caused by an acquired or genetic defect in the neurohypophysis. The aim of this study was to identify any autonomic dysfunction (AD) in patients with DI as a possible cofactor responsible for their reportedly higher mortality. The study involved 12 patients (6 females) with central idiopathic DI and a well-controlled electrolyte balance, and 12 controls matched for age, sex and cardiovascular risk factors, who were assessed using the tilt, lying-to-standing, hand grip, deep breath, Valsalva maneuver and Stroop tests. The tilt test showed a significantly more pronounced decrease in both systolic (- 20.67 ± 18 vs. - 1.92 ± 6.99mmHg, p = 0.0009) and diastolic blood pressure (- 10.5 ± 14.29 vs. - 1.5 ± 5mmHg, p = 0.012) in patients than in controls. Three patients with DI had to suspend the test due to the onset of syncope. The lying-to-standing test also revealed a marked reduction in blood pressure in patients with DI (1.05 ± 0.13 vs. 1.53 ± 0.14, p = 0.0001). Similar results emerged for the Valsalva maneuver (Valsalva ratio, 1.24 ± 0.19 vs. 1.79 ± 0.11, p < 0.0001) and deep breath test (1.08 ± 0.11 vs. 1.33 ± 0.08, p < 0.0001). All the principal autonomic tests performed in the study were concordant in indicating that patients with central DI have an impaired autonomic nervous system function despite a normal hydroelectrolytic balance under desmopressin therapy. This impairment may reflect damage to the autonomic system per se and/or the absence of any vasoactive effect of AVP on vascular smooth muscle. In our opinion, patients with central DI should be educated on how to prevent orthostatic hypotension, and pharmacological treatment should be considered for patients with a more marked impairment.

Effectiveness of acarbose in treating elderly patients with diabetes with postprandial hypotension

Postprandial hypotension (PPH) is a common condition that occurs primarily in elderly patients with type 2 diabetes mellitus (T2DM). This study aimed to assess the effectiveness of acarbose for PPH;...

Risk stratification for the primary prevention of arrhythmic sudden cardiac death in postinfarction patients

AbstractSudden cardiac death (SCD) threatens ischemic cardiomyopathy patients. Antiarrhythmic protection may be provided to these patients with implanted cardiac defibrillators (ICD), after an efficient risk stratification approach. The proposed risk stratifier of an impaired left ventricular ejection fraction has limited sensitivity. Current risk stratification strategies focus on markers that, by identifying the arrhythmic substrate and the severity of the arrhythmia mechanisms present, are also considered to quantify the risk of SCD. Such markers reflect: (1) myocardial substrate lesions and postinfarction fibrosis (LVEF, QRS, LBBB, SAECG, fragmented QRS, CMR, PVBs, NSVT), (2) abnormal repolarization (QT, QTd, T‐wave alternans, QT/RR, QTVI, TWV), (3) impaired autonomic nervous system function (HR, heart rate variability (HRV), HRT, deceleration capacity (DC), BRS, HR recovery after exercise), and (4) inducibility on programmed ventricular stimulation during electrophysiological testing. Ventricular tachyarrhythmias have a strong dynamic component because transient and unpredictable factors can trigger a fatal arrhythmic episode. For this reason, SCD risk stratification is not simple and no ideal marker or a completely successful predictive model is existing. The evolution of technology made possible all the noninvasive markers to be incorporated in the Holter software. Noninvasive risk stratification has been simplified. Innovative Holter technology enforced the doctors, providing them with the tools for primarily screening their patients through the ICD protection process.Answer questions and earn CME: https://wileyhealthlearning.com/Activity2/4469459/Activity.aspx

Reduced Heart Rate Recovery Is Associated with Poorer Cognitive Function in Older Adults with Cardiovascular Disease

Cardiovascular disease (CVD) in older adults has been associated with varying degrees of cognitive dysfunction. Several mechanisms may explain this association, including impaired cardiovascular reactivity to autonomic nervous system (ANS) signaling. Reduced heart rate recovery following a stress test may be considered an indication of impaired ANS function (i.e., reduced parasympathetic activity). Participants were 47 older adults (53–83 years) who underwent a treadmill stress test and were administered a comprehensive neuropsychological battery upon entry to phase II cardiac rehabilitation. Reduced parasympathetic activity was associated with impaired cognitive performance on a measure of global cognitive function and on tasks of speeded executive function and confrontation naming. These relationships suggest that changes in autonomic function may be mechanistically related to the impaired cognitive function prevalent in CVD patients.

Increased Yin-Deficient Symptoms and Aggravated Autonomic Nervous System Function in Patients with Metastatic Cancer

The objectives of this study were to investigate the differences in severity of yin-deficiency syndrome (YDS) and function of the autonomic nervous system (ANS) between patients with cancer with metastasis and those without metastasis. The setting was an outpatient clinic in a teaching hospital in central Taiwan. The subjects were a total of 124 patients who had been diagnosed with cancer on the basis of pathologic and clinical findings. Among them, 61 had distant metastasis, and the other 63 had no evidence of metastasis. The two groups were similar in terms of age and gender. The severity of YDS in each subject was evaluated using a questionnaire containing 12 items about symptoms and signs related to YDS. The severity of each symptom or sign was rated on a 4-point scale. The total score on the questionnaire represented the severity of YDS. ANS function in each subject was evaluated by measuring heart rate variability (HRV), including time and frequency domains. The questionnaire data were coded, and statistical analysis was performed using SPSS version 12.0. Data were analyzed using the Student's t test or the χ(2) test. The patients with metastasis had significantly higher average total YDS score and heart rate compared with the patients without metastasis. In contrast, they had significantly lower HRV, including standard deviation of the 5-minute average R-R interval, total power, very-low-frequency power, and low frequency (LF) power, but not high-frequency (HF) power and LF/HF ratio. The results of this study indicate that patients with metastatic cancer have more severe YDS and impaired ANS function than those without metastasis.

Heat stroke in familial dysautonomia

A 14-month-old female with familial dysautonomia was referred to the pediatric department with high fever (41.6°C), watery diarrhea, and vomiting. A few hours later, signs of encephalopathy appeared. Laboratory tests revealed elevated levels of lactate dehydrogenase (3500 U/L), aspartate aminotransferase (640 U/L), alanine aminotransferase (320 U/L), and creatine kinase (28,420 U/L). The diagnosis was heat stroke. Impaired autonomic nervous system function may be another risk factor for the development of heat stroke in young children.

Novocain blockade of stellate nodes in the treatment of patients with diffuse neurodermatitis

Impaired autonomic nervous system function in diffuse neurodermatitis is now generally recognized, with the crucial importance believed to be not generalized, but local dystonia of both parts of the autonomic nervous system. Studies carried out in diffuse neurodermatitis have shown significant disturbances in catecholamine excretion. A decrease in urinary excretion of adrenaline and a marked increase in norepinephrine excretion were observed during the exacerbation period of the dermatosis. Despite many existing methods of treatment, therapy of patients with diffuse neurodermatitis is often a difficult task in the practice of a dermatologist.