Exercise heart rate reserve and recovery as risk factors for sudden cardiac death.

BACKGROUND: Little is known if heart rate responses during and after exercise test may be associated with the risk of sudden cardiac death (SCD). Our aim was to determine if exercise heart rate reserve and recovery, providing non-invasive indices, may predict SCD risk in general male population. METHODS: We evaluated the impact of delayed heart rate reserve and slow heart rate recovery and the risk of SCD in the Kuopio Ischemic Heart Disease prospective cohort study of randomly selected 1967 men aged 42-61 years at recruitment. Heart rate reserve was calculated as the difference between the maximal attained heart rate and resting heart rate, whereas heart rate recovery was defined as maximal heart rate minus the heart rate measured at 2 min of recovery, on a symptom-limited cardiopulmonary exercise testing. RESULTS: During a median follow-up interval of 25 years, 209 events of SCD occurred. The age and examination adjusted relative hazards of SCD were in the lowest third of heart rate reserve 3.86 (95% confidence interval (CI) 2.56-5.80, p < 0.001) and the lowest third of heart rate recovery 2.86 (95% CI 1.95-4.20, p < 0.001) as compared to men in the highest third of heart rate reserve and heart rate recovery, respectively. After adjusting for potential confounders, the respective relative hazards were 1.96 (95% CI 1.24-3.12) and 1.75 (95% CI 1.16-2.64). Each unit increment (1 beat/min) in heart rate reserve and heart rate recovery decreased the incidence of SCD by 1-2%. CONCLUSIONS: Delayed exercise heart rate reserve and slow heart rate recovery predicted the risk of SCD, suggesting that heart rate responses may be associated with an increased risk for SCD in general population.

ß-Blockers for traumatic brain injury: A systematic review and meta-analysis.

BACKGROUND: Paroxysmal sympathetic hyperactivity (PSH) and catecholamine surge, which are associated with poor outcome, may be triggered by traumatic brain injury (TBI).ß Adrenergic receptor blockers (ß-blockers), as potential therapeutic agents to prevent paroxysmal sympathetic hyperactivity and catecholamine surge, have been shown to improve survival after TBI. The principal aim of this study was to investigate the effect of ß-blockers on outcomes in patients with TBI. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, EMBASE, and Cochrane Library databases from inception to September 25, 2020, for randomized controlled trials, nonrandomized controlled trials, and observational studies reporting the effect of ß-blockers on the following outcomes after TBI: mortality, functional measures, and cardiopulmonary adverse effects of ß-blockers (e.g., hypotension, bradycardia, and bronchospasm). With use of random-effects model, we calculated pooled estimates, confidence intervals (CIs), and odds ratios (ORs) of all outcomes. RESULTS: Fifteen studies with 12,721 patients were included. Exposure to ß-blockers after TBI was associated with a significant reduction in adjusted in-hospital mortality (OR, 0.39; 95% CI, 0.30-0.51; I2 = 66.3%; p < 0.001). ß-Blockers significantly improved the long-term (≥6 months) functional outcome (OR, 1.75; 95% CI, 1.09-2.80; I2 = 0%; p = 0.02). Statistically significant difference was not seen for cardiopulmonary adverse events (OR, 0.91; 95% CI, 0.55-1.50; I2 = 25.9%; p = 0.702). CONCLUSION: This meta-analysis demonstrated that administration of ß-blockers after TBI was safe and effective. Administration of ß-blockers may therefore be suggested in the TBI care. However, more high-quality trials are needed to investigate the use of ß-blockers in the management of TBI. LEVEL OF EVIDENCE: Systematic review and meta-analysis, level III.

The impact of supine hypertension on target organ damage and survival in patients with synucleinopathies and neurogenic orthostatic hypotension.

INTRODUCTION: In addition to neurogenic orthostatic hypotension (nOH), patients with synucleinopathies frequently have hypertension when supine. The long-term consequences of both abnormalities are difficult to disentangle. We aimed to determine if supine hypertension is associated with target organ damage and worse survival in patients with nOH. METHODS: Patients with nOH due to multiple system atrophy (MSA), Parkinson disease (PD), or pure autonomic failure (PAF) were classified into those with or without supine hypertension (systolic BP of at least 140 mmHg or diastolic BP of at least 90 mmHg). Organ damage was assessed by measuring cerebral white matter hyperintensities (WMH), left ventricular hypertrophy (LVH), and renal function. We prospectively followed patients for 30 months (range: 12-66 months) and recorded incident cardiovascular events and all-cause mortality. RESULTS: Fifty-seven patients (35 with probable MSA, 14 with PD and 8 with PAF) completed all evaluations. In addition to nOH (average fall 35 ± 21/17 ± 14 mmHg, systolic/diastolic, mean ± SD), 38 patients (67%) had supine hypertension (systolic BP > 140 mmHg). Compared to those without hypertension, patients with hypertension had higher blood urea nitrogen levels (P = 0.005), lower estimated glomerular filtration rate (P = 0.008), higher prevalence of LVH (P = 0.040), and higher WMH volume (P = 0.019). Longitudinal follow-up of patients for over 2 years (27.1 ± 14.5 months) showed that supine hypertension was independently associated with earlier incidence of cardiovascular events and death (HR = 0.25; P = 0.039). CONCLUSIONS: Supine hypertension in patients with nOH was associated with an increased risk for target organ damage, cardiovascular events, and premature death. Defining management strategies and safe blood pressure ranges in patients with nOH remains an important research question.

Cardiovascular autonomic neuropathy in type 2 diabetic patients.

Diabetes is one of the most common chronic pathologies around the world, involving treatment with general clinicians, endocrinologists, cardiologists, ophthalmologists, nephrologists and a multidisciplinary team. Patients with type 2 Diabetes Mellitus (T2DM) can be affected by cardiac autonomic neuropathy, leading to increased mortality and morbidity. In this review, we will present current concepts, clinical features, diagnosis, prognosis, and possible treatment. New drugs recently developed to reduce glycemic level presented a pleiotropic effect of reducing sudden death, suggesting a potential use in patients at risk.

Cardiovascular autonomic neuropathy in type 2 diabetic patients

SUMMARY Diabetes is one of the most common chronic pathologies around the world, involving treatment with general clinicians, endocrinologists, cardiologists, ophthalmologists, nephrologists and a multidisciplinary team. Patients with type 2 Diabetes Mellitus (T2DM) can be affected by cardiac autonomic neuropathy, leading to increased mortality and morbidity. In this review, we will present current concepts, clinical features, diagnosis, prognosis, and possible treatment. New drugs recently developed to reduce glycemic level presented a pleiotropic effect of reducing sudden death, suggesting a potential use in patients at risk.

RESUMO Diabetes é uma das mais frequentes patologias crônicas em todo o mundo, cujo tratamento envolve uma equipe multidisciplinar, médicos generalistas, endocrinologistas, cardiologistas, nefrologistas e oftalmologistas. Pacientes com diabetes mellitus tipo 2 (DMT2) podem apresentar neuropatia autonômica cardíaca (NAC), levando a aumento de mortalidade e morbidade. Nesta revisão, apresentaremos atuais conceitos, características clínicas, diagnóstico, prognóstico e possíveis tratamentos. Novas drogas recentemente desenvolvidas para redução de níveis glicêmicos apresentaram efeito pleiotrópico de redução de morte súbita, sugerindo um potencial uso neste perfil de pacientes.

Percutaneous mastoid electrical stimulator alleviates autonomic dysfunction in patients with acute ischemic stroke.

BACKGROUND AND PURPOSE: Poststroke prognosis is associated with autonomic status. The purpose of our study was to determine whether percutaneous mastoid electrical stimulator (PMES) can alleviate abnormal heart rate variability (HRV) and improve clinical outcome. METHODS: This prospective, randomized, double-blinded, placebo-controlled study enrolled a total of 140 patients with autonomic dysfunction within 3d after acute ischemic stroke. The patients were treated with PMES or sham stimulation once daily over a period of 2 weeks. HRV was primarily assessed by the fractal dimension (FD) at admission and 2 weeks. All patients were followed up for 3 months. The clinical outcome was death and major disability (modified Rankin Scale score≥ 3) at 3 months after acute ischemic stroke. RESULTS: FD of the 2-week treatment period increased in PMES groups. PMES can significantly alleviate abnormal HRV. The difference in FD of the 2-week treatment period between the PMES and sham groups was significant (1.14 ± 0.27 vs. 1.00 ± 0.23; P = 0.001). In fully adjusted models, PMES was associated with reduced 3-month mortality (adjusted odds ratio, 0.32; 95% confidence interval, 0.11-0.93; P = 0.036). No significant group differences were seen in three major disability and composite outcome (P > 0.05). CONCLUSIONS: PMES was a safe, effective, and low-cost therapy to alleviate HRV and could significantly reduce mortality in the early recovery phase after acute ischemic stroke.

Cholinergic Crisis Caused by Cholinesterase Inhibitors: a Retrospective Nationwide Database Study.

INTRODUCTION: In contrast to information on the effects of organophosphate, pesticide, or environmental exposures, data on cholinergic crisis caused by pharmaceutical cholinesterase inhibitors are sparse. The present study aimed to describe the characteristics, demographics, and mortality of patients with cholinergic crisis caused by pharmaceutical cholinesterase inhibitors using a nationwide inpatient database in Japan. METHODS: We identified patients diagnosed with cholinergic crisis as a result of taking cholinesterase inhibitor medications in the Japanese Diagnosis Procedure Combination inpatient database from July 2010 to March 2016. We examined the patients' characteristics, treatments, and mortality. RESULTS: A total of 235 patients with cholinergic crisis were identified during the 69-month study period. Forty-eight patients required mechanical ventilation (20.4%), and 15 patients died (6.4%) in hospital. The median lengths of hospital stay and intensive care unit stay were 15 days (interquartile range, 6-42) and 4 days (2-8), respectively. Approximately half of all hospitalized patients required catecholamines, atropine, or mechanical ventilation, while the other half did not require any of these treatments. Patients who required catecholamines, atropine, or mechanical ventilation were more likely to die and had longer hospital stays. CONCLUSIONS: Cholinergic crisis caused by pharmaceutical cholinesterase inhibitors is a rare but potentially life-threatening condition. Patients who require mechanical ventilation and catecholamines or atropine have a poorer prognosis.

Autonomic Dysfunction Predicts Clinical Outcomes After Acute Ischemic Stroke: A Prospective Observational Study.

BACKGROUND AND PURPOSE: Central autonomic dysfunction increases stroke morbidity and mortality. We aimed to investigate whether poststroke autonomic dysfunction graded by Ewing battery can predict clinical outcome. METHODS: In this prospective observational study, we assessed autonomic function of ischemic stroke patients within 7 days from symptom onset by Ewing battery. On the basis of the magnitude of autonomic dysfunction, we stratified patients into significant (definite, severe, or atypical) or minor (normal or early) autonomic function impairment groups and correlated the impairment with the 3-month modified Rankin Scale score (good outcome: modified Rankin Scale score 0≈2; poor outcome: modified Rankin Scale score 3≈6). RESULTS: Among the 150 patients enrolled (mean age, 66.4±9.9 years; 70.7% males), minor autonomic dysfunction was identified in 36 patients (24.0%), and significant autonomic dysfunction was identified in 114 patients (76.0%) based on Ewing battery. In 3 months, a poor functional outcome was found in 32.5% of significant group patients compared with 13.9% in the minor group (P=0.031). Crude odds ratios of the magnitude of autonomic dysfunction and 3-month unfavorable functional outcome after acute ischemic stroke were 2.979 (95% confidence interval, 1.071-8.284; P=0.036). After adjusting for confounding variables with statistical significance between the 2 functional outcome subgroups identified in univariate analysis (including sex and National Institutes of Health Stroke Scale score on admission), the magnitude of autonomic dysfunction still independently predicted an unfavorable outcome, with an odds ratio of 3.263 (95% confidence interval, 1.141-9.335; P=0.027). CONCLUSIONS: Autonomic dysfunction gauged by Ewing battery predicts poor functional outcome after acute ischemic stroke.

Synergic Impact of Vascular Calcification and Low Autonomic Tone in Mortality of Hemodialysis Patients.

BACKGROUND: Both cardiovascular calcification and autonomic dysfunction are frequently encountered in hemodialysis patients. We aimed to investigate the relationship between cardiovascular calcification and heart rate variability (HRV) and their influence on long-term outcome. METHODS: Seventy-eight hemodialysis patients underwent echocardiogram and radiography of the pelvis and hands to identify valvular and vascular calcification. HRV was evaluated using a commercial machine. RESULTS: Based on the average, the patients were divided into higher and lower subgroups of high frequency (HF) and low frequency (LF) respectively. Patients with higher LF were younger and were found to have a lower proportion of diabetes. Their hemoglobin, albumin, and bone morphogenic protein (BMP)-7 levels were significantly higher and both high-sensitive C-reactive protein (hs-CRP) and osteoprotegerin levels were lower (all p < 0.05). In patients of the higher HF group, the proportion of diabetes was lower but they were found to have higher levels of BMP-7 and lower levels of hs-CRP, interleukin-6 (all p < 0.05). Significantly higher LF and HF were noted in patients without vascular calcification, but only hand artery (HA) calcification was negatively correlated with both LF and HF in multivariate analysis. Low LF and high hs-CRP were the independent predictors of mortality. Coexistence of low LF band and HA calcification was associated with the worse outcome. CONCLUSIONS: Abnormal autonomic nervous function was closely related to inflammation and mortality in hemodialysis patients. Calcification of HA was associated with autonomic dysfunction and patients with lower autonomic tone and HA calcification had the highest mortality rate in this population.

Insomnia and Risk of Cardiovascular Disease.

Insomnia is the most prevalent sleep disorder in the United States and has high comorbidity with a number of cardiovascular diseases (CVDs). In the past decade, a number of observational studies have demonstrated an association between insomnia and incident cardiovascular disease (CVD) morbidity and mortality, including hypertension (HTN), coronary heart disease (CHD), and heart failure (HF). Despite some inconsistencies in the literature, likely due to variations in how insomnia is defined and measured, the existing data suggest that insomnia, especially when accompanied by short sleep duration, is associated with increased risk for HTN, CHD and recurrent acute coronary syndrome, and HF. Purported mechanisms likely relate to dysregulation of the hypothalamic-pituitary axis, increased sympathetic nervous system activity, and increased inflammation. This paper reviews the most recent studies of insomnia and CVD and the potential pathophysiological mechanisms underlying this relationship and highlights the need for randomized trials to further elucidate the nature of the relationship between insomnia and CVD.

Assessment of late anthracycline-induced cardiotoxicity by 123I-mIBG cardiac scintigraphy in patients treated during childhood and adolescence.

PURPOSE: The goal of this study was to evaluate late cardiotoxic effects of anthracyclines (ATC) by evaluating cardiac sympathetic activity in a cohort of asymptomatic patients previously treated with ATC for childhood cancers. METHODS: We studied 89 asymptomatic patients previously treated with ATC with a normal echocardiogram (49 men and 40 women) and a control group of 40 healthy individuals (26 men and 14 women). Both groups underwent planar myocardial 123I-meta-iodobenzylguanidine scintigraphy (123I-mIBG). From these images, the early and late heart-to-mediastinum (H/M) ratio and washout rate (WR) were assessed. RESULTS: The mean survival at the time of the 123I-mIBG scintigraphy was 5.3 ± 3.4 years. Patients treated with ATC had a lower but clinical normal left ventricular ejection fraction (LVEF) compared to controls (60.44 ± 6.5 vs 64.1 ± 6.0%, P < 0.01). Both the late H/M ratio and WR were not able to discriminate ATC treated patients from controls. The cumulative ATC dose was the only independent predictor of the LVEF, explaining approximately 12% of the variation in LVEF (P = 0.01). CONCLUSIONS: Although the pathophysiology behind ATC cardiotoxicity is most likely multifactorial, myocardial sympathetic activity is not associated with a reduction in LVEF 5-years after completion of chemotherapy.

Autonomic Impairment in Severe Traumatic Brain Injury: A Multimodal Neuromonitoring Study.

OBJECTIVES: Autonomic impairment after acute traumatic brain injury has been associated independently with both increased morbidity and mortality. Links between autonomic impairment and increased intracranial pressure or impaired cerebral autoregulation have been described as well. However, relationships between autonomic impairment, intracranial pressure, impaired cerebral autoregulation, and outcome remain poorly explored. Using continuous measurements of heart rate variability and baroreflex sensitivity we aimed to test whether autonomic markers are associated with functional outcome and mortality independently of intracranial variables. Further, we aimed to evaluate the relationships between autonomic functions, intracranial pressure, and cerebral autoregulation. DESIGN: Retrospective analysis of a prospective database. SETTING: Neurocritical care unit in a university hospital. SUBJECTS: Sedated patients with severe traumatic brain injury. MEASUREMENTS AND MAIN RESULTS: Waveforms of intracranial pressure and arterial blood pressure, baseline Glasgow Coma Scale and 6 months Glasgow Outcome Scale were recorded. Baroreflex sensitivity was assessed every 10 seconds using a modified cross-correlational method. Frequency domain analyses of heart rate variability were performed automatically every 10 seconds from a moving 300 seconds of the monitoring time window. Mean values of baroreflex sensitivity, heart rate variability, intracranial pressure, arterial blood pressure, cerebral perfusion pressure, and impaired cerebral autoregulation over the entire monitoring period were calculated for each patient. Two hundred and sixty-two patients with a median age of 36 years entered the analysis. The median admission Glasgow Coma Scale was 6, the median Glasgow Outcome Scale was 3, and the mortality at 6 months was 23%. Baroreflex sensitivity (adjusted odds ratio, 0.9; p = 0.02) and relative power of a high frequency band of heart rate variability (adjusted odds ratio, 1.05; p < 0.001) were individually associated with mortality, independently of age, admission Glasgow Coma Scale, intracranial pressure, pressure reactivity index, or cerebral perfusion pressure. Baroreflex sensitivity showed no correlation with intracranial pressure or cerebral perfusion pressure; the correlation with pressure reactivity index was strong in older patients (age, > 60 yr). The relative power of high frequency correlated significantly with intracranial pressure and cerebral perfusion pressure, but not with pressure reactivity index. The relative power of low frequency correlated significantly with pressure reactivity index. CONCLUSIONS: Autonomic impairment, as measured by heart rate variability and baroreflex sensitivity, is significantly associated with increased mortality after traumatic brain injury. These effects, though partially interlinked, seem to be independent of age, trauma severity, intracranial pressure, or autoregulatory status, and thus represent a discrete phenomenon in the pathophysiology of traumatic brain injury. Continuous measurements of heart rate variability and baroreflex sensitivity in the neuromonitoring setting of severe traumatic brain injury may carry novel pathophysiological and predictive information.

The influence of cardiovascular autonomic neuropathy on mortality in type 1 diabetic patients; 10-year follow-up.

AIM: The aim of our retrospective study was to answer the question if the presence of cardiovascular autonomic neuropathy (CAN) affects mortality in type 1 diabetic patients during a 10-year follow-up. METHODS: Patients with type 1 diabetes mellitus examined for CAN in 2003 were enrolled in this retrospective study. A total of 278 patients were included and divided into two groups according to the presence or absence of CAN (111 CAN+, 167 CAN-). The group characteristics and outcomes were compared at baseline and after ten years (in 2013). RESULTS: In the follow-up period, a total of 18 patients died; CAN+ (14/111; 12.6%) and CAN- (4/167; 2.4%) (P < 0.001). At baseline, the CAN+ patients were older (47 vs. 33 years; P < 0.001), had longer duration of diabetes (20 vs. 12 years; P < 0.05), had worse glycemic control assessed by HbA1c (73 vs. 68 mmol/mol; P < 0.05), higher systolic (130 vs. 120 mmHg; P < 0.001) and diastolic (80 vs. 70 mmHg; P < 0.01) blood pressure and had more diabetic complications. In our analysis we found the strongest predictor of mortality to be the presence of CAN (P < 0.01) and the blood pressure value at baseline (P < 0.05). Other baseline characteristics, including the duration of diabetes, age and the presence of micro- and macrovascular complications were not significant. The statistical analysis was performed using logistic regression step-wise analysis. CONCLUSIONS: During the 10-year follow-up, CAN+ patients had a 5-fold higher mortality rate than CAN- patients. The strongest predictor of mortality was the presence of CAN.

Autonomic Imbalance as a Predictor of Metabolic Risks, Cardiovascular Disease, Diabetes, and Mortality.

CONTEXT: Identifying novel early predictors of metabolic disorders is essential to improving effective primary prevention. OBJECTIVES: The objectives were to examine the contribution of two measures of autonomic imbalance, resting heart rate (RHR) and heart rate variability (HRV), on the development of five metabolic risk outcomes, and on cardiovascular disease, diabetes, and early mortality. DESIGN: This study was a secondary analysis of prospective data from Offspring Cohort participants (N = 1882) in the Framingham Heart Study (FHS). PARTICIPANTS: Participants at FHS Exam 3 (1983-1987) with 1) age years 18 or older, and 2) data on RHR, HRV, and five measures of metabolic risk (blood pressure, fasting glucose, triglycerides, high-density lipoprotein [HDL] cholesterol, and body mass index [BMI]) at three follow-up visits over 12 years. We conducted a backward elimination variable selection procedure on a logistic regression model, using baseline RHR, HRV, age, sex, and smoking status to predict the odds of developing a specific metabolic risk. OUTCOMES: Measures included hyperglycemia, high blood pressure, high triglycerides, low HDL cholesterol, and high BMI over 12 years; incident diabetes, cardiovascular disease, and early mortality over 20 years. RESULTS: RHR and HRV, along with sex, age, and smoking were significant predictors of high blood pressure, hyperglycemia, and a diagnosis of diabetes within 12 years. RHR and HRV also predicted the development of cardiovascular disease and early mortality for most of the sample. CONCLUSIONS: In this community sample two measures of autonomic imbalance predicted multiple poor metabolic outcomes and mortality, making autonomic imbalance a potentially worthy target for intervention studies to reduce risks for cardiovascular disorders, diabetes, and early death.

Diabetic autonomic neuropathy.

Diabetes mellitus is the commonest cause of an autonomic neuropathy in the developed world. Diabetic autonomic neuropathy causes a constellation of symptoms and signs affecting cardiovascular, urogenital, gastrointestinal, pupillomotor, thermoregulatory, and sudomotor systems. Several discrete syndromes associated with diabetes cause autonomic dysfunction. The most prevalent of these are: generalized diabetic autonomic neuropathy, autonomic neuropathy associated with the prediabetic state, treatment-induced painful and autonomic neuropathy, and transient hypoglycemia-associated autonomic neuropathy. These autonomic manifestations of diabetes are responsible for the most troublesome and disabling features of diabetic peripheral neuropathy and result in a significant proportion of the mortality and morbidity associated with the disease.

Severe autonomic failure as a predictor of mortality in aortic valve stenosis.

BACKGROUND: Identification of new risk markers in aortic valve stenosis (AS) is of great interest. Here, we hypothesized that the presence of severe autonomic failure (SAF) is an important prognostic marker in both, symptomatic patients undergoing invasive treatment for severe AS, and in asymptomatic patients with severe AS who were primarily treated conservatively. METHODS: We prospectively enrolled 300 patients with severe AS (aortic valve area<1.0 cm2 or mean aortic gradient>40 mmHg) in sinus rhythm. All patients underwent a 24-h Holter recording for assessment of heart rate turbulence (HRT) and deceleration capacity (DC). Patients with both, abnormal DC and HRT were considered to suffer from SAF. RESULTS: The first hypothesis was tested in 216 symptomatic patients who underwent successful aortic valve replacement (AVR) or transcatheter aortic valve implantation (TAVI). During follow-up of 2 years, 29 of these patients died. SAF was the strongest independent predictor of mortality (hazard ratio 5.6, 95% confidence interval 2.6-12.0; p<0.001) with 2-year mortality rates of 50.0% and 10.7% in SAF-positive and SAF-negative patients, respectively (p<0.001). The second hypothesis was tested in 71 patients, who were asymptomatic at study entry and for whom a primarily conservative treatment strategy was proposed. During follow-up, 10 of these patients died. SAF also predicted death in asymptomatic patients with 2-year mortality rates of 52.4% and 8.7% in SAF-positive and SAF-negative patients, respectively (p=0.010). CONCLUSIONS: SAF is a strong and independent predictor of mortality in symptomatic and asymptomatic patients with severe AS.

Early diagnosis of paroxysmal sympathetic hyperactivity in the ICU.

BACKGROUND: Paroxysmal sympathetic hyperactivity (PSH) is a complication of acquired brain injury manifesting with episodic tachycardia, tachypnea, hypertension, diaphoresis, hypertonia, and posturing. No universally accepted diagnostic criteria exist and diagnosis is often delayed until the rehabilitation phase. METHODS: Electronic records were screened to identify consecutive cases of PSH diagnosed in an intensive care unit (ICU) between 1/2006 and 8/2012 and assess the validity of early clinical diagnosis against formal diagnostic criteria. Data collected included patient demographics, brain injury etiology, symptoms noted by the clinician to support the diagnosis of PSH, PSH manifestations, therapeutic interventions, relevant brain imaging, and investigations to exclude alternative diagnoses. An operational set of diagnostic criteria based on previous literature was used for comparison. RESULTS: Fifty-three consecutive patients with PSH were identified. Mean age was 33.6 ± 14.5 years (range 16-67). Traumatic brain injury was the most common etiology (30 patients, 56.6 %) but causes were diverse. Mean time to diagnosis was 8.3 ± 11.0 days; 31 patients (59 %) were diagnosed within 7 days and 20 patients (38 %) within 3 days of admission. Tachycardia was almost uniformly present, and diaphoresis, fever, hypertension, and tachypnea were also present in most cases. Dystonia and posturing were present in less than half of patients. 89 % of clinically diagnosed cases met formal diagnostic criteria. CONCLUSIONS: Paroxysmal sympathetic hyperactivity can be diagnosed early in the ICU. Strict diagnostic criteria supported the clinician's diagnosis in the majority of cases. Diagnosis should not be rejected because of any particular sign's absence, especially dystonia and posturing.

Autonomic deficit not the cause of death in West Nile virus neurological disease.

INTRODUCTION: Some West Nile virus (WNV)-infected patients have been reported to manifest disease signs consistent with autonomic dysfunction. Moreover, WNV infection in hamsters causes reduced electromyography amplitudes of the gastrointestinal tract and diaphragm, and they have reduced heart rate variability (HRV), a read-out for the parasympathetic autonomic function. METHODS: HRV was measured in both hamsters and mice using radiotelemetry to identify autonomic deficits. To identify areas of WNV infection within the medulla oblongata mapping to the dorsal motor nucleus of vagus (DMNV) and the nucleus ambiguus (NA), fluorogold dye was injected into the cervical trunk of the vagus nerve of hamsters. As a measurement of the loss of parasympathetic function, tachycardia was monitored contiguously over the time course of the disease. RESULTS: Decrease of HRV did not occur in all animals that died, which is not consistent with autonomic function being the mechanism of death. Fluorogold-stained cells in the DMNV were not stained for WNV envelope protein. Fourteen percent of WNV-stained cells were co-localized with fluorogold-stained cells in the NA. These data, however, did not suggest a fatal loss of autonomic functions because tachycardia was not observed in WNV-infected hamsters. CONCLUSION: Parasympathetic autonomic function deficit was not a likely mechanism of death in WNV-infected rodents and possibly in human patients with fatal WN neurological disease.

The natural history of multiple system atrophy: a prospective European cohort study.

BACKGROUND: Multiple system atrophy (MSA) is a fatal and still poorly understood degenerative movement disorder that is characterised by autonomic failure, cerebellar ataxia, and parkinsonism in various combinations. Here we present the final analysis of a prospective multicentre study by the European MSA Study Group to investigate the natural history of MSA. METHODS: Patients with a clinical diagnosis of MSA were recruited and followed up clinically for 2 years. Vital status was ascertained 2 years after study completion. Disease progression was assessed using the unified MSA rating scale (UMSARS), a disease-specific questionnaire that enables the semiquantitative rating of autonomic and motor impairment in patients with MSA. Additional rating methods were applied to grade global disease severity, autonomic symptoms, and quality of life. Survival was calculated using a Kaplan-Meier analysis and predictors were identified in a Cox regression model. Group differences were analysed by parametric tests and non-parametric tests as appropriate. Sample size estimates were calculated using a paired two-group t test. FINDINGS: 141 patients with moderately severe disease fulfilled the consensus criteria for MSA. Mean age at symptom onset was 56·2 (SD 8·4) years. Median survival from symptom onset as determined by Kaplan-Meier analysis was 9·8 years (95% CI 8·1-11·4). The parkinsonian variant of MSA (hazard ratio [HR] 2·08, 95% CI 1·09-3·97; p=0·026) and incomplete bladder emptying (HR 2·10, 1·02-4·30; p=0·044) predicted shorter survival. 24-month progression rates of UMSARS activities of daily living, motor examination, and total scores were 49% (9·4 [SD 5·9]), 74% (12·9 [8·5]), and 57% (21·9 [11·9]), respectively, relative to baseline scores. Autonomic symptom scores progressed throughout the follow-up. Shorter symptom duration at baseline (OR 0·68, 0·5-0·9; p=0·006) and absent levodopa response (OR 3·4, 1·1-10·2; p=0·03) predicted rapid UMSARS progression. Sample size estimation showed that an interventional trial with 258 patients (129 per group) would be able to detect a 30% effect size in 1-year UMSARS motor examination decline rates at 80% power. INTERPRETATION: Our prospective dataset provides new insights into the evolution of MSA based on a follow-up period that exceeds that of previous studies. It also represents a useful resource for patient counselling and planning of multicentre trials.