Cardiovascular Autonomic Research Articles

Chronic Fatigue in Adult Survivors of Childhood Cancer: Associated Symptoms, Neuroendocrine Markers, and Autonomic Cardiovascular Responses

Chronic fatigue (CF) is a common late effect after childhood cancer. Based on findings among patients with the chronic fatigue syndrome (CFS), this study explored symptoms, neuroendocrine markers, and autonomic cardiovascular responses associated with CFS in childhood cancer survivors. Long-term survivors of childhood lymphoma and acute lymphoblastic leukemia reporting CF were compared with survivors without CF. Data included patient-reported outcomes, clinical examination, head-up tilt test, and neuroendocrine markers in the blood and the urine. Of 102 included survivors, 15 were excluded from comparative analyses because of significant co-morbidity or pregnancy. Of the remaining 87 participants (median age 33.0 years, follow-up time 25.2 years), 35 had CF and 52 did not have CF. Compared with non-CF controls, CF cases reported a significantly (P < 0.01) higher frequency of symptoms typical of the CFS (muscle or joint pain or both and feeling confused/disoriented) and symptoms of autonomic dysfunction (palpitations, feeling intermittently heat and cold, and watery diarrhea). CF cases and controls did not differ regarding autonomic cardiovascular responses to orthostatic stress, but the CF group had lower levels of plasma adrenocorticotrophic hormone (P = 0.002) and higher levels of urine norepinephrine (P = 0.017). Survivors with CF reported a high symptom-burden compared with controls. There were few differences between both the groups regarding biomarkers, but slight alterations of the hypothalamus-pituitary-adrenal axis and sympathetic nervous activity were detected. CF in cancer survivors has features in common with the CFS, but further efforts are required to clarify the pathophysiology.

Autonomic Cardiovascular Damage during Post-menopause: the Role of Physical Training

Menopause is part of the aging process and is characterized by the natural cessation of menstruation; during this time, the production of ovarian hormones, especially estrogen, is sharply reduced. This reduction can cause symptoms and disorders that affect most women and can interfere with their quality of life. Women are also more susceptible to cardiovascular diseases during this period, considering that these ovarian hormones would be associated with a protective effect on the cardiovascular system, by acting at various levels, contributing to the body homeostasis. Among several effects on the cardiovascular system, the ovarian hormones seem to play an important role in the autonomic control of heart rate and blood pressure. A reduction in ovarian hormones causes an autonomic imbalance and increases the risk of cardiovascular diseases. In fact, this increased risk is justified by the key role the autonomic nervous system plays in all cardiac regulatory mechanisms, exerting a tonic and reflexive influence on the main variables of the cardiovascular system. The autonomic system controls various cardiovascular parameters, such as the modulation of heart rate and blood pressure, myocardial contractility and venous capacitance, directly participating in the regulation of cardiac output. Over the years, the standard treatment for menopause symptoms and disorders has been hormone replacement therapy (HRT). However, many studies have indicated the risks of HRT, which justify the need for new non-pharmacological therapies. To this end, physical training, mainly aerobic, has been applied with excellent results on the cardiovascular autonomic nervous system, as it reduces the risk of cardiac diseases and improves the survival rate with direct beneficial effects on the quality of life of these women during the aging process.

Circadian Rhythm of Autonomic Cardiovascular Control During Mars500 Simulated Mission to Mars

The Mars500 project was conceived to gather knowledge about the psychological and physiological effects of living in an enclosed environment during 520 d as would be required for a real mission to Mars. Our objective was to investigate the circadian profile of heart rate variability (HRV) in the context of the Mars500 study. Before, during, and after confinement, 24-h EKG records were obtained from the six crewmembers who participated in the mission. Autonomic activity was evaluated through time and frequency domain indexes of HRV analysis. Circadian rhythmicity was assessed both by averaging hourly HRV along wake and sleep scheduled periods and by fitting a 24-h harmonic to the hourly means. During confinement, wake HRV showed (mean +/- SE) a progressive increase in mean RR interval (from 778 +/- 24 ms to 916 +/- 42 ms), and in the amplitude (values are wavelet power coefficients) of very low (from 13.3 +/- 0.3 to 14.1 +/- 0.2) and high (from 7.8 +/- 0.4 to 8.3 +/- 0.3) frequency components. During sleep, the relative amplitude of the high frequency component of HRV decreased (from 11.8 +/- 1.6 to 9.4 +/- 1.8 normalized units). Overall, sleep-wake differences of HRV showed a progressive decrease of the relative amplitude of the high frequency component. Also, circadian HRV rhythms were dampened during confinement. Data revealed diminished amplitude of the rest-activity pattern of the autonomic nervous system parasympathetic function. Reduced daylight exposure and mood changes could account for this observation.

Comparison of Prediction Model for Cardiovascular Autonomic Dysfunction Using Artificial Neural Network and Logistic Regression Analysis

BackgroundThis study aimed to develop the artificial neural network (ANN) and multivariable logistic regression (LR) analyses for prediction modeling of cardiovascular autonomic (CA) dysfunction in the general population, and compare the prediction models using the two approaches.Methods and MaterialsWe analyzed a previous dataset based on a Chinese population sample consisting of 2,092 individuals aged 30–80 years. The prediction models were derived from an exploratory set using ANN and LR analysis, and were tested in the validation set. Performances of these prediction models were then compared.ResultsUnivariate analysis indicated that 14 risk factors showed statistically significant association with the prevalence of CA dysfunction (P<0.05). The mean area under the receiver-operating curve was 0.758 (95% CI 0.724–0.793) for LR and 0.762 (95% CI 0.732–0.793) for ANN analysis, but noninferiority result was found (P<0.001). The similar results were found in comparisons of sensitivity, specificity, and predictive values in the prediction models between the LR and ANN analyses.ConclusionThe prediction models for CA dysfunction were developed using ANN and LR. ANN and LR are two effective tools for developing prediction models based on our dataset.

Artificial neural network models for prediction of cardiovascular autonomic dysfunction in general Chinese population

BackgroundThe present study aimed to develop an artificial neural network (ANN) based prediction model for cardiovascular autonomic (CA) dysfunction in the general population.MethodsWe analyzed a previous dataset based on a population sample consisted of 2,092 individuals aged 30–80 years. The prediction models were derived from an exploratory set using ANN analysis. Performances of these prediction models were evaluated in the validation set.ResultsUnivariate analysis indicated that 14 risk factors showed statistically significant association with CA dysfunction (P < 0.05). The mean area under the receiver-operating curve was 0.762 (95% CI 0.732–0.793) for prediction model developed using ANN analysis. The mean sensitivity, specificity, positive and negative predictive values were similar in the prediction models was 0.751, 0.665, 0.330 and 0.924, respectively. All HL statistics were less than 15.0.ConclusionANN is an effective tool for developing prediction models with high value for predicting CA dysfunction among the general population.

A risk score of cardiovascular autonomic dysfunction for targeted screening in the Chinese population

Cardiovascular autonomic (CA) dysfunction has become a major health concern in China following rapid lifestyle changes [1,2]. Individuals with previously undiagnosed CA dysfunction have an unfavorable cardiovascular risk profile [3,4]. Delay and lack of detection of the disease mostly results from patients being asymptomatic during its early stages [5,6]; therefore, the development of a simple and accurate screening tool to identify those at high risk of developing CA dysfunction will be of great value. The aim of this study was to develop and evaluate a simple, noninvasive and informative scoring system to characterize individuals according to their future risk of CA dysfunction. This study is a CA dysfunction factor survey carried out in a random sample of Chinese population [7]. Survey participants with undiagnosed CA dysfunction, aged 30–80 years, were included in this study. Subjects were excluded from the study to eliminate potential confounding factors thatmayhave influenced theirCA function [7].Of these subjects, complete baseline datawere obtained for 2092 (69.46%) of the participantswithout prior CA dysfunction history. Written consent was obtained from all patients before the study. The present study was approved by the Ethics Committee of the Huashan Hospital, Shanghai, China. The subjects were interviewed for the documentation of medical histories and medication, laboratory assessment of cardiovascular disease risk factors, and standardized examination for HRV. All study subjects underwent a complete CA function evaluation after an eighthour fast. CAdysfunctionwas diagnosed based on at least two abnormal CA reflex test results [5]. The potential risk factors for CA dysfunction were age (categorized into three groups: ≤50, 51–60, and N60 years; code 0, 1 and 2), gender, BMI, abdominal obesity (WC ≥ °90 inmen and≥80 cm inwomen; code 0 and 1), current smoking, resting HR (categorized into four groups: ≤70, 71–80, 81–90, and N90 bpm; code 0, 1, 2and 3), diabetes, hypertension (HT, code 0 and 1), blood glucose and lipid profile. Univariate analyses were performed to estimate significant predictors of CA dysfunction.Multiple logistic regression (MLR)was used to compute β-coefficients for known risk factors. Only parameters that are easy to assess without any laboratory tests were entered into the model. Variables significant at 5% were included in the MLR using stepwise elimination, with CA dysfunction as the dependent variable. For each significant variable in theMLR analysis, a risk scorewas calculated by the regression coefficients (β) dividing by a common factor (0.10) and rounding to the nearest integer. A sum score was calculated for each participant by adding the score for each variable in the risk model. A receiver-operating characteristic (ROC) curve and area under the curve (AUC)wereproduced. Sensitivityandspecificitywere calculated foreach cutoff score. The cutoff score that gave the maximum sum of sensitivity and specificity was taken as the optimum. The performance of the risk scorewas evaluatedbyusing theAUC inROC curve, sensitivity, specificity, the positive predictive value (PPV), and the negative predictive value (NPV) in the three different sets. Furthermore, the proportion of individuals who needed subsequent testing (NST) was compared. The baseline characteristics of the 2092 subjects were listed in Table 1. The CA dysfunction prevalence was 18.51% in entire sample. A total of 1066 individuals and 1026 individuals were randomly selected to be the exploratory set and validation set, respectively. The baseline characteristics were similar between the exploratory and validation set (p b 0.05, Table 1). Univariate association analysis to include potential risk factors showed that resting HR, DM, SBP, DBP, HT, BMI, WC, age, TG, and IRwere significantly associatedwith CAdysfunction. After stepwise elimination of the non-significant variables, the final MLR model included risk factors of age, WC, HT, and HR. The risk score was calculatedusing the formula of 4*age + 3*WC+ 5*HT+7*HR. The total score ranged from 0 to 37. In exploratory set, the cutoff score of 16 was optimum (sensitivity =69.78%, specificity = 69.30%, Youden index = 39.08%,

Noninvasive Assessment of Autonomic Cardiovascular Activity in Patients With Inappropriate Sinus Tachycardia

Inappropriate sinus tachycardia (IST) is a clinical syndrome characterized by excessive resting heart rate (HR) or disproportional HR increase during exercise. The etiology of IST has not been fully elucidated and remains controversial. The aim of the present study was to assess autonomic function by means of noninvasive tests and commonly available electrocardiographic methods in a series of consecutive patients with symptomatic IST. Twenty-four patients (37 ± 12 years; 20 women) with IST were enrolled. Six cardiovascular reflex tests were performed: (1) HR variation during slow deep breathing, (2) 30-to-15 ratio during active standing, (3) blood pressure response to standing, (4) cold face test, (5) Valsalva maneuver, and (6) blood pressure response to sustained handgrip. Intrinsic HR was calculated and compared with HR after pharmacologic denervation. Additionally, spontaneous baroreflex sensitivity and 24-hour HR variability indices were analyzed. In IST patients, intrinsic HR was significantly higher compared with control subjects. Most cardiovascular autonomic tests revealed abnormal or borderline results, particularly those reflecting mainly parasympathetic function. The spontaneous baroreflex gain was significantly reduced in IST patients. After controlled orthostatic stress and during Valsalva maneuver, impaired baroreflex function was observed. The sympathovagal balance from HR variability was preserved, but altered activity in both bands of frequency domain analysis was recorded. In conclusion, IST is a heterogenic syndrome with enhanced sinus node automaticity modulated by complex alterations of autonomic tone.

Cardiac Autonomic Function and Cardiovascular Response to Exercise in Patients with Chronic Obstructive Pulmonary Disease

Background: Chronic obstructive pulmonary disease (COPD) is associated with impaired exercise tolerance, but it has not been established to what extent cardiac autonomic function impacts on exercise capacity. Objective: To evaluate whether there is an association between airflow limitation and cardiac autonomic function and whether cardiac autonomic function plays a role in exercise intolerance and daily physical activity (PA) in patients with COPD. Methods: Univariate and multivariate analyses were performed to evaluate the association between both 6-minute walking test (6MWT) and PA (steps per day) and pulmonary function, cardiac autonomic function (HR at rest, HRR and heart rate variability, HRV) in patients with COPD. Results: In 154 COPD patients (87 females, mean [SD]: age 62.5 [10.7] years, FEV1%predicted (43.0 [19.2]%), mean HR at rest was elevated (86.4 [16.4] beats/min) and HRV was reduced (33.69 [28.96] ms) compared to published control data. There was a significant correlation between FEV1 and HR at rest (r = -0.32, p < 0.001), between HR at rest and 6MWD (r = -0.26, p = 0.001) and between HR at rest and PA (r = -0.29, p = 0.010). No correlation was found between HRV and 6MWD (r = 0.089, p = 0.262) and PA (r = 0.075, p = 0.322). In multivariate analysis both HR and FEV1 were independent predictors of exercise capacity in patients with COPD. Conclusions: In patients with COPD the degree of airflow limitation is associated with HR at rest. The degree of airflow limitation and cardiac autonomic function, as quantified by HR at rest, are independently associated with exercise capacity in patients with COPD.

A unified point process probabilistic framework to assess heartbeat dynamics and autonomic cardiovascular control.

In recent years, time-varying inhomogeneous point process models have been introduced for assessment of instantaneous heartbeat dynamics as well as specific cardiovascular control mechanisms and hemodynamics. Assessment of the model’s statistics is established through the Wiener-Volterra theory and a multivariate autoregressive (AR) structure. A variety of instantaneous cardiovascular metrics, such as heart rate (HR), heart rate variability (HRV), respiratory sinus arrhythmia (RSA), and baroreceptor-cardiac reflex (baroreflex) sensitivity (BRS), are derived within a parametric framework and instantaneously updated with adaptive and local maximum likelihood estimation algorithms. Inclusion of second-order non-linearities, with subsequent bispectral quantification in the frequency domain, further allows for definition of instantaneous metrics of non-linearity. We here present a comprehensive review of the devised methods as applied to experimental recordings from healthy subjects during propofol anesthesia. Collective results reveal interesting dynamic trends across the different pharmacological interventions operated within each anesthesia session, confirming the ability of the algorithm to track important changes in cardiorespiratory elicited interactions, and pointing at our mathematical approach as a promising monitoring tool for an accurate, non-invasive assessment in clinical practice. We also discuss the limitations and other alternative modeling strategies of our point process approach.

Is sleep apnea a potential link between major depressive disorder and cardiovascular disease?

Depression Cytokines Nitric oxide Nitric oxide synthase Asymmetrical dimethyl arginine Endothelial dysfunction Endothelial progenitor cells Platelet aggregability Autonomic imbalance Continuous positive airway pressure Cardiovascular disease Hypertension

Aberrances in Autonomic Cardiovascular Regulation in Fibromyalgia Syndrome and Their Relevance for Clinical Pain Reports

To investigate autonomic cardiovascular regulation in fibromyalgia syndrome (FMS). In 35 patients and 29 healthy controls, electrocardiography, impedance cardiography, and finger continuous blood pressure measurements were conducted. Assessed parameters comprised blood pressure, R-R interval (RRI), heart rate variability, baroreflex sensitivity (BRS), stroke volume, and left ventricular ejection time (LVET). To evaluate cardiovascular autonomic reactivity to mental stress, parameters were obtained at rest and during an arithmetic task. As an estimate of clinical pain severity, participants completed the McGill Pain Inventory. Patients exhibited lower power in all heart rate variability frequency bands (p < .05), lower BRS (7.13 +/- 3.45 versus 10.73 +/- 5.72 ms/mmHg), as well as reduced stroke volume, LVET, and RRI (p < .05). Stress-induced modulations were less pronounced in BRS, LVET, blood pressure, and RRI (all p < .05). Across the whole sample and in both subgroups, BRS (r = -.40) and blood pressure (r = -.39) correlated negatively with pain severity. The data suggest that autonomic cardiovascular regulation in FMS is impaired in terms of reduced sympathetic and parasympathetic influences, as well as baroreflex malfunctioning. Furthermore, autonomic cardiovascular adjustment to acute stress is blunted. The inverse association between BRS and pain severity reflects the well-documented pain inhibition through the baroreceptor system. On account of this and the reduced baroreflex function in FMS, one may assume deficient ascending pain inhibition arising from the cardiovascular system, which may contribute to hyperalgesia that is characteristic of the disorder.

Influence of Age on Linear and Nonlinear Measures of Autonomic Cardiovascular Modulation

Age has been identified as an independent risk factor for cardiovascular diseases. In addition, autonomic imbalance toward sympathetic preponderance has been shown to facilitate the occurrence of heart disease. Here, we aimed to assess autonomic modulation of cardiovascular parameters during normal ageing applying well-established linear and novel nonlinear parameters. Linear and nonlinear measures of heart rate variability and complexity as well as measures of QT interval variability and baroreflex sensitivity were obtained from a total of 131 healthy, medication-free participants from a continuous age range between 20 and 90 years, who were allocated to three different age groups. Heart rate variability and complexity significantly decreased with age, while regularity of heart rate time series increased. In addition, QT interval variability linearly increased with age, while baroreflex sensitivity showed a pronounced decrease. Overall, concerning effects of ageing, linear and nonlinear parameters showed equal differentiation between groups. These data indicate a shift of autonomic balance toward sympathetic predominance in higher age groups, limiting the reactiveness of the cardiovascular system to adjust to different demands and increasing the risk for developing tachyarrhythmias.

Global Disturbances in Autonomic Function Yield Cardiovascular Instability and Hypertension in the Chromogranin A Null Mouse

We reported previously that chromogranin A (Chga) knockout (KO) mice are hypertensive and hyperadrenergic. Here we sought to determine the basis of such alterations by probing physiological, biochemical, and pharmacological responses to perturbations of the autonomic nervous system. In the conscious state, KO mice had substantially elevated basal high blood pressure (BP) and heart rate (HR); immobilization stress caused increments in systolic BP and HR in both wild-type (WT) and KO mice, with higher maxima but blunted increments in the KO state. Catestatin (CST; CHGA(352-372)) selectively diminished stress-induced increments in BP and HR in KO mice, implicating CST as an antihypertensive peptide, even in stressful conditions. Heightened plasma catecholamines in KO mice returned to WT level after CST. Stress caused further increments in catecholamines in WT mice but no change in KO mice. KO mice displayed diminished baroreflex sensitivity in response to either phenylephrine or sodium nitroprusside, accounting for exaggerated pressor and depressor responses to these compounds; baroreceptor function was normalized by CST. To probe the relative roles of endogenous/basal sympathetic vs. parasympathetic tone in control of BP and HR, we used the muscarinic-cholinergic antagonist atropine or the beta-adrenergic antagonist propranolol; HR and BP responses to each antagonist were exaggerated in KO animals. We conclude that ablation of Chga expression results in global disturbances in autonomic function, both sympathetic and parasympathetic, that can be abrogated (or rescued), at least in part, by replacement of CST. The results point to mechanisms whereby CHGA and its CST fragment act to control cardiovascular homeostasis.

Effects of Chronic Baroreceptor Stimulation on the Autonomic Cardiovascular Regulation in Patients With Drug-Resistant Arterial Hypertension

In patients with drug-resistant hypertension, chronic electric stimulation of the carotid baroreflex is an investigational therapy for blood pressure reduction. We hypothesized that changes in cardiac autonomic regulation can be demonstrated in response to chronic baroreceptor stimulation, and we analyzed the correlation with blood pressure changes. Twenty-one patients with drug-resistant hypertension were prospectively included in a substudy of the Device Based Therapy in Hypertension Trial. Heart rate variability and heart rate turbulence were analyzed using 24-hour ECG. Recordings were obtained 1 month after device implantation with the stimulator off and after 3 months of chronic electric stimulation (stimulator on). Chronic baroreceptor stimulation decreased office blood pressure from 185+/-31/109+/-24 mm Hg to 154+/-23/95+/-16 mm Hg (P<0.0001/P=0.002). Mean heart rate decreased from 81+/-11 to 76+/-10 beats per minute(-1) (P=0.001). Heart rate variability frequency-domain parameters assessed using fast Fourier transformation (FFT; ratio of low frequency:high frequency: 2.78 versus 2.24 for off versus on; P<0.001) were significantly changed during stimulation of the carotid baroreceptor, and heart rate turbulence onset was significantly decreased (turbulence onset: -0.002 versus -0.015 for off versus on; P=0.004). In conclusion, chronic baroreceptor stimulation causes sustained changes in heart rate variability and heart rate turbulence that are consistent with inhibition of sympathetic activity and increase of parasympathetic activity in patients with drug-resistant systemic hypertension; these changes correlate with blood pressure reduction. Whether the autonomic modulation has favorable cardiovascular effects beyond blood pressure control should be investigated in further studies.

T1252 The Selective 5-HT 1A Antagonist, AZD7371 (Robalzotan Tartrate Monohydrate), Inhibits Pain-Related Visceromotor, But Not Autonomic Cardiovascular, Responses to Colorectal Distension in Rats

T1252 The Selective 5-HT 1A Antagonist, AZD7371 (Robalzotan Tartrate Monohydrate), Inhibits Pain-Related Visceromotor, But Not Autonomic Cardiovascular, Responses to Colorectal Distension in Rats

Effects of Bilateral Stellate Ganglion Block on Autonomic Cardiovascular Regulation

Stellate ganglion block (SGB) is performed for the diagnosis and treatment of sympathetic dependent pain in the head, neck and upper limbs. However, the effects of bilateral SGB on cardiovascular and autonomic regulation remain unknown. The aim of this study was to assess the effects of bilateral SGB on cardiovascular and autonomic function by measuring heart rate variability (HRV), systolic blood pressure variability (SBPV) and spontaneous baroreflex sensitivity (SBRS). Twenty healthy volunteers were randomly allocated to receive right or left SGB with 8 ml 1% lidocaine solution; after 20 min, the contralateral side SGB was performed. Changes in the RR interval (RRI), systolic blood pressure (SBP), HRV, SBPV and SBRS were assessed before and after bilateral SGB. The low-frequency (LF, 0.04-0.15 Hz) and high-frequency (HF, 0.15-0.4 Hz) components of HRV and SBRS decreased significantly; however, no significant changes were found in RRI, SBP and the LF and HF components of SBPV after bilateral SGB. In subjects with symptoms of vagal blockade, HRV, SBP and SBRS were significantly affected by bilateral SGB. Bilateral SGB should be performed cautiously because it can reduce cardiac vagal modulation and BRS, especially for those with symptoms of vagal blockade after bilateral SGB.

Effect of Rapid Ascent to High Altitude on Autonomic Cardiovascular Modulation

Effect of acute hypobaric hypoxia on autonomic nervous activities remains unclear. We evaluated the effect of rapid ascent to high altitude on autonomic cardiovascular modulation and compared the differences between the subjects with and without acute mountain sickness (AMS). Twenty-seven unacclimatized healthy subjects were included for this study. The sleep and study altitude (3180 m) was reached by car from low level (555 m) within 3 hours. The stationary spectral heart rate variability was measured 3 days before ascent (T0), 2 nights at high altitude (T1 and T2), and 2 days after descent (T3). AMS occurrence was evaluated by the Lake Louise score system. At high altitude, RR intervals (RRI), standard deviation of RRI (SDRR), total power (TP), low-frequency power (LF), high-frequency power (HF), and normalized HF decreased significantly but normalized LF and LF/HF ratio increased significantly in subjects irrespective of AMS. AMS developed in 13 of 27 (48.1%) subjects. Compared with the data at T1, SDRR, TP, LF, and HF increased at T2 in AMS group but decreased in non-AMS group, and the differences in these variables (data at T2 minus data at T1) between the 2 groups showed statistical significance. After rapid ascent to high altitude, autonomic nervous activities were suppressed and sympathetic activity was relatively predominant. At high altitude, the discordant changes in SDRR, TP, LF, and HF may reflect varying capacity of acute hypobaric hypoxic adaptation between the subjects with and without AMS.

Stroke-Induced Sudden-Autonomic Death

See related article, pages 2425–2431. Stroke is the third leading cause of death.1,2 Fatal outcome has been primarily related to acute or chronic complications of stroke-induced executive deficits, such as muscle weakness, swallowing disorders, respiratory dysfunction with pneumonia, or cardiac complications.3,4 Only during the last 10 or 15 years has there been an increasing interest in and knowledge of associations between cerebral lesions and altered influences of the central autonomic nervous system on cardiovascular and respiratory function.5–7 Oppenheimer et al8–10 suggested a role of the insular cortex in the pathophysiology of sudden death. The group extensively assessed topographically distinct interactions of the left and the right insular cortex with heart rate and blood pressure control.11 There was agreement that insular cortex lesions essentially contribute to clinically relevant alterations of cardiovascular control.8 In this issue of Stroke , Rincon and coworkers present an analysis of associations between ischemic stroke location and fatal cardiac outcome, based on the epidemiological data of the Northern Manhattan Stroke study (NOMAS).12,13 Considering neurological syndromes and neuroimaging findings, the authors analyzed outcome during a 5-year follow-up period. Mortality rates or nonfatal myocardial infarctions, and particularly sudden unexpected or unwitnessed death, were associated with the location of brain infarctions. Apart from age, male gender, the National Institutes of Health Stroke Scale (NIHSS), and a history of coronary artery disease, the authors identified infarct locations in the frontal, parietal, temporal lobe, and …

Effect of Dialysate Temperature and Diabetes on Autonomic Cardiovascular Regulation during Hemodialysis

Background/Aims: Lowering dialysate temperature to increase intradialytic hemodynamic stability may interfere with the ultrafiltration-dependent intradialytic autonomic cardiovascular regulation. The present study aimed to investigate hemodynamic and autonomic responses depending on dialysate temperature and the presence of diabetes. Methods: Seventeen (8 diabetic, 9 non-diabetic) hypotension-resistant patients were alternately treated at dialysate temperatures of 37 and 35°C. Hemodynamic parameters, heart rate variability (HRV) and baroreceptor reflex sensitivity (BRRS) were measured noninvasively. Power spectral analysis of HRV was used to evaluate cardiac sympathetic and parasympathetic activity. Results: In contrast to diabetic patients who showed an overall reduced autonomic activity and a blunted autonomic response, in non-diabetic patients cardiac sympathetic activity increased during dialysis (p < 0.05) resulting in a shift in sympathovagal balance towards sympathetic predominance. This response was not altered by dialysate temperature. Significant decreases in stroke volume and cardiac output were found in both patient groups. Total peripheral resistance increased in diabetic (p < 0.05) and in non-diabetic patients (p < 0.01) at both dialysate temperatures. No differences in BRRS were determined. Conclusion: The presence of diabetes has great impact on the cardiovascular autonomic regulation during hemodialysis. Varying the dialysate temperature does not influence cardiovascular autonomic regulation in hemodynamically stable diabetic and non-diabetic patients.

Altered Autonomic Cardiovascular Regulation After Combined Deep and Superficial Cervical Plexus Blockade for Carotid Endarterectomy

Survey of Anesthesiology: October 2007 - Volume 51 - Issue 5 - p 241-242 doi: 10.1097/SA.0b013e318149fb11