Complete remission with histamine blocker in a patient with intractable hyperadrenergic postural orthostatic tachycardia syndrome secondary to long coronavirus disease syndrome.

The COVID-19 pandemic caused by the novel severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), has emerged as a global public health concern and its sequels have barely started to outcrop. A good percentage of patients who suffered from COVID-19 are prone to develop long-COVID or post-COVID condition (PCC), a multisystemic, heterogeneous, chronic disorder. Patients with PCC may experience diverse manifestations, of which cardiovascular and neurological symptoms are among the most frequently reported. Indeed, dysautonomia presented as orthostatic intolerance has gained room following recent reports linking postural orthostatic tachycardia syndrome (POTS) with PCC. Disturbances in heart rate (HR) and blood pressure (BP) during postural changes are the cornerstones of orthostatic intolerance seen in patients suffering from PCC. A subtype of POTS, hyperadrenergic POTS, has been widely studied because of its association with mast cell activation syndrome (MCAS). Although a causative relationship between PCC, hyperadrenergic POTS, and MCAS remains unrevealed, these syndromes can overlap. We want to propose here a correlation produced by a close-loop mechanism with positive feedback established after SARS-CoV-2 infection in a previously healthy young patient.

Optogenetic and Chemogenic Control of Pain Signaling: Molecular Markers.

Pain is a complex experience that involves physical, emotional, and cognitive aspects. This review focuses specifically on the physiological processes underlying pain perception, with a particular emphasis on the various types of sensory neurons involved in transmitting pain signals to the central nervous system. Recent advances in techniques like optogenetics and chemogenetics have allowed researchers to selectively activate or inactivate specific neuronal circuits, offering a promising avenue for developing more effective pain management strategies. The article delves into the molecular targets of different types of sensory fibers such as channels, for example, TRPV1 in C-peptidergic fiber, TRPA1 in C-non-peptidergic receptors expressed differentially as MOR and DOR, and transcription factors, and their colocalization with the vesicular transporter of glutamate, which enable researchers to identify specific subtypes of neurons within the pain pathway and allows for selective transfection and expression of opsins to modulate their activity.

Predictors of Mechanical Ventilation in Guillain-Barré Syndrome with Axonal Subtypes.

BACKGROUND: The early clinical predictors of respiratory failure in Latin Americans with Guillain-Barré syndrome (GBS) have scarcely been studied. This is of particular importance since Latin America has a high frequency of axonal GBS variants that may imply a worse prognosis. METHODS: We studied 86 Mexican patients with GBS admitted to the Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, a referral center of Mexico City, to describe predictors of invasive mechanical ventilation (IMV). RESULTS: The median age was 40 years (interquartile range: 26-53.5), with 60.5% men (male-to-female ratio: 1.53). Most patients (65%) had an infectious antecedent (40.6% gastrointestinal). At admission, 38% of patients had a Medical Research Council (MRC) sum score <30. Axonal subtypes predominated (60.5%), with acute motor axonal neuropathy being the most prevalent (34.9%), followed by acute inflammatory demyelinating polyneuropathy (32.6%), acute motor sensory axonal neuropathy (AMSAN) (25.6%), and Fisher syndrome (7%). Notably, 15.1% had onset in upper limbs, 75.6% dysautonomia, and 73.3% pain. In all, 86% received either IVIg (9.3%) or plasma exchange (74.4%). IMV was required in 39.5% patients (72.7% in AMSAN). A multivariate model without including published prognostic scores yielded the time since onset to admission <15 days, axonal variants, MRC sum score <30, and bulbar weakness as independent predictors of IMV. The model including grading scales yielded lower limbs onset, Erasmus GBS respiratory insufficiency score (EGRIS) >4, and dysautonomia as predictors. CONCLUSION: These results suggest that EGRIS is a good prognosticator of IMV in GBS patients with a predominance of axonal electrophysiological subtypes, but other early clinical data should also be considered.

Sex Differences in the Physiological Network of Healthy Young Subjects.

Within human physiology, systemic interactions couple physiological variables to maintain homeostasis. These interactions change according to health status and are modified by factors such as age and sex. For several physiological processes, sex-based distinctions in normal physiology are present and defined in isolation. However, new methodologies are indispensable to analyze system-wide properties and interactions with the objective of exploring differences between sexes. Here we propose a new method to construct complex inferential networks from a normalization using the clinical criteria for health of physiological variables, and the correlations between anthropometric and blood tests biomarkers of 198 healthy young participants (117 women, 81 men, from 18 to 27 years old). Physiological networks of men have less correlations, displayed higher modularity, higher small-world index, but were more vulnerable to directed attacks, whereas networks of women were more resilient. The networks of both men and women displayed sex-specific connections that are consistent with the literature. Additionally, we carried out a time-series study on heart rate variability (HRV) using Physionet's Fantasia database. Autocorrelation of HRV, variance, and Poincare's plots, as a measure of variability, are statistically significant higher in young men and statistically significant different from young women. These differences are attenuated in older men and women, that have similar HRV distributions. The network approach revealed differences in the association of variables related to glucose homeostasis, nitrogen balance, kidney function, and fat depots. The clusters of physiological variables and their roles within the network remained similar regardless of sex. Both methodologies show a higher number of associations between variables in the physiological system of women, implying redundant mechanisms of control and simultaneously showing that these systems display less variability in time than those of men, constituting a more resilient system.

Cardiovascular dysautonomia in Achalasia Patients: Blood pressure and heart rate variability alterations.

Achalasia is a disease characterized by the inability to relax the esophageal sphincter due to a degeneration of the parasympathetic ganglion cells located in the wall of the thoracic esophagus. Achalasia has been associated with extraesophageal dysmotility, suggesting alterations of the autonomic nervous system (ANS) that extend beyond the esophagus. The purpose of the present contribution is to investigate whether achalasia may be interpreted as the esophageal manifestation of a more generalized disturbance of the ANS which includes alterations of heart rate and/or blood pressure. Therefore simultaneous non-invasive records of the heart inter-beat intervals (IBI) and beat-to-beat systolic blood pressure (SBP) of 14 patients (9 female, 5 male) with achalasia were compared with the records of 34 rigorously screened healthy control subjects (17 female, 17 male) in three different conditions: supine, standing up, and controlled breathing at 0.1 Hz, using a variety of measures in the time and spectral domains. Significant differences in heart rate variability (HRV) and blood pressure variability (BPV) were observed which seem to be due to cardiovagal damage to the heart, i.e., a failure of the ANS, as expected according to our hypothesis. This non-invasive methodology can be employed as an auxiliary clinical protocol to study etiology and evolution of achalasia, and other pathologies that damage ANS.

Clinical and neurophysiological description of patients with POEMS syndrome.

INTRODUCTION: POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, skin changes) is a monoclonal gammopathy with polyneuropathy as a mandatory criterion. OBJECTIVE: To describe potential associations between clinical expression and electrodiagnostic patterns in POEMS syndrome. METHOD: Observational, retrospective, cross-sectional study of cases cared for in a referral center, diagnosed with POEMS syndrome from 2009 to 2019. RESULTS: Eleven patients (8 men) were analyzed. Median age at diagnosis was 40 years (range: 31-51; mean: 37.19 ± 15.67 years). Mean latency at diagnosis was 9.7 ± 8.37 months. In all subjects, initial clinical manifestation was polyneuropathy. Most patients had an axonal pattern (n = 5), followed by demyelinating (n = 4) and mixed patterns (n = 2). Monoclonal gammopathy was observed in all (6 l and 5 k cases; immunoglobulin [Ig] G: 72 %; IgA: 18 %; IgM: 9 %). Medical Research Council sum score was lower in the axonal pattern (median: 37.00 vs. 45.5; p = 0.024). There were no differences in systemic involvement between electrophysiological patterns. CONCLUSION: Electrophysiological patterns are unlikely to have a clear extra-neurological clinical correspondence; however, this will have to be definitively proven with a larger sample size.

INTRODUCCIÓN: El síndrome POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, skin changes) es una gammapatía monoclonal con polineuropatía como criterio obligatorio. OBJETIVO: Describir las potenciales asociaciones entre la expresión clínica y los patrones de electrodiagnóstico en el síndrome POEMS. MÉTODO: Estudio observacional, retrospectivo y transversal de los casos atendidos en un centro de referencia con diagnóstico de síndrome de POEMS de 2009 a 2019. RESULTADOS: Se analizó a 11 pacientes (8 hombres). La mediana de la edad al diagnóstico fue de 40 años (rango: 31-51, media: 37.19 ± 15.67 años). La latencia media al diagnóstico fue de 9.7 ± 8.37 meses. En todos la manifestación clínica inicial fue la polineuropatía. La mayoría de los pacientes presentaron un patrón axonal (n = 5), seguido del desmielinizante (n = 4) y mixto (n = 2). La gammapatía monoclonal se observó en todos (6 casos l y 5 k, inmunoglobulina [Ig] G: 72%, IgA: 18%, IgM: 9%). El Medical Research Council sum score fue menor en el patrón axonal (medianas: 37.00 vs. 45.5, p = 0.024). No se presentaron diferencias en la afección sistémica entre patrones electrofisiológicos. CONCLUSIÓN: Es poco probable que los patrones electrofisiológicos tengan una correspondencia clínica extraneurológica clara, sin embargo, esto deberá probarse de forma definitiva con un mayor tamaño de muestra.

A physicist's view of homeostasis: how time series of continuous monitoring reflect the function of physiological variables in regulatory mechanisms.

OBJECTIVE: Homeostasis is one of the key concepts of physiology and the basis to understand chronic-degenerative disease and human ageing, but is difficult to quantify in clinical practice. The variability of time series resulting from continuous and non-invasive physiological monitoring is conjectured to reflect the underlying homeostatic regulatory processes, but it is not clear why the variability of some variables such as heart rate gives a favourable health prognosis whereas the variability of other variables such as blood pressure implies an increased risk factor. The purpose of the present contribution is to quantify homeostasis using time-series analysis and to offer an explanation for the phenomenology of physiological time series. APPROACH: Within the context of network physiology, which focusses on the interactions between various variables at multiple scales of time and space, it may be understood that different physiological variables may play distinct roles in their respective regulatory mechanisms. In the present contribution, we distinguish between regulated variables, such as blood pressure or core temperature, and physiological responses, such as heart rate and skin temperature. MAIN RESULTS: We give evidence that in optimal conditions of youth and health the former are characterized by Gaussian statistics, low variability and represent the stability of the internal environment, whereas the latter are characterized by non-Gaussian distributions, large variability and reflect the adaptive capacity of the human body; in the adverse conditions of ageing and/or disease, adaptive capacity is lost and the variability of physiological responses is diminished, and as a consequence the stability of the internal environment is compromised and its variability increases. SIGNIFICANCE: Time-series analysis allows one to quantify homeostasis in the optimal conditions of youth and health and the degradation of homeostasis or homeostenosis in the adverse conditions of ageing and/or disease, and may offer an alternative approach to diagnosis in clinical practice.

The charming physician (El médico encantador): neurological conditions in a short story by Silvina Ocampo.

The Argentinian author Silvina Ocampo (1903-1993) left us a vast body of works which are considered outstanding in many ways. In 1960, she published a short story, entitled "El médico encantador" (The Charming Physician), in the renowned literary magazine Sur. The central character of this piece is a family doctor named Albino Morgan, who had a secret truth: in any house he visited, all variety of disease also entered. He brought with him the viruses he disseminated. The narrator of this short story-one of his patients-describes four of Morgan's diseases. These imaginary neurological conditions allowed Ocampo to explore improbable situations in everyday life.

The charming physician (El médico encantador): neurological conditions in a short story by Silvina Ocampo / O médico encantador (El médico encantador): doenças neurológicas em um conto de Silvina Ocampo

ABSTRACT The Argentinian author Silvina Ocampo (1903-1993) left us a vast body of works which are considered outstanding in many ways. In 1960, she published a short story, entitled "El médico encantador" (The Charming Physician), in the renowned literary magazine Sur. The central character of this piece is a family doctor named Albino Morgan, who had a secret truth: in any house he visited, all variety of disease also entered. He brought with him the viruses he disseminated. The narrator of this short story—one of his patients—describes four of Morgan's diseases. These imaginary neurological conditions allowed Ocampo to explore improbable situations in everyday life.

RESUMO A autora argentina Silvina Ocampo (1903-1993) deixou-nos uma vasta obra que é considerada excelente de várias maneiras. Em 1960, publicou um conto, intitulado "El médico encantador" (O médico encantador), na famosa revista literária Sur. O personagem principal desta obra é um médico de família chamado Albino Morgan que possuía uma verdade secreta: em qualquer casa que ele visitava, também entrava toda a diversidade de doenças. O narrador deste conto -um dos seus pacientes- descreve quatro das doenças de Morgan. Estas condições neurológicas imaginárias permitiu a Ocampo explorar as situações improváveis da vida quotidiana.

Loss of Breathing Modulation of Heart Rate Variability in Patients with Recent and Long Standing Diabetes Mellitus Type II.

Healthy subjects under rhythmic breathing have heart interbeat intervals with a respiratory band in the frequency domain that can be an index of vagal activity. Diabetes Mellitus Type II (DM) affects the autonomic nervous system of patients, thus it can be expected changes on the vagal activity. Here, the influence of DM on the breathing modulation of the heart rate is evaluated by analyzing in the frequency domain heart interbeat interval (IBI) records obtained from 30 recently diagnosed, 15 long standing DM patients, and 30 control subjects during standardized clinical tests of controlled breathing at 0.1 Hz, supine rest and standing upright. Fourier spectral analysis of IBI records quantifies heart rate variability in different regions: low-frequencies (LF, 0.04-0.15 Hz), high-frequencies (HF, 0.15-0.4 Hz), and a controlled breathing peak (RP, centered around 0.1 Hz). Two new parameters are introduced: the frequency radius rf (square root of the sum of LF and HF squared) and ß (power of RP divided by the sum of LF and HF). As diabetes evolves, the controlled breathing peak loses power and shifts to smaller frequencies, indicating that heart rate modulation is slower in diabetic patients than in controls. In contrast to the traditional parameters LF, HF and LF/HF, which do not show significant differences between the three populations in neither of the clinical tests, the new parameters rf and ß, distinguish between control and diabetic subjects in the case of controlled breathing. Sympathetic activity that is driven by the baroreceptor reflex associated with the 0.1 Hz breathing modulations is affected in DM patients. Diabetes produces not only a rigid heartbeat with less autonomic induced variability (rf diminishes), but also alters the coupling between breathing and heart rate (reduced ß), due to a progressive decline of vagal and sympathetic activity.

[On roman philonium]. / Sobre el filonio romano.

The roman philonium (Philonium Romanum) is an example of pharmacological poetry. This opiate was conceived by Philo of Tarsus, who was active during the first century of the Common Era. His antidote was written in elegiac couplets. The conservation of these couplets is owed to Galen, who reproduced them in the ninth book of On the Composition of Medicines according to the Places. Most of this Galenic treatise has not been translated into Spanish. For the first time, we offer this prescription in our language from a French version of the fin de siècle. Additionally, we attempt an exegesis of Philo's poem.

Heart Rate and Systolic Blood Pressure Variability in the Time Domain in Patients with Recent and Long-Standing Diabetes Mellitus.

Diabetes Mellitus (DM) affects the cardiovascular response of patients. To study this effect, interbeat intervals (IBI) and beat-to-beat systolic blood pressure (SBP) variability of patients during supine, standing and controlled breathing tests were analyzed in the time domain. Simultaneous noninvasive measurements of IBI and SBP for 30 recently diagnosed and 15 long-standing DM patients were compared with the results for 30 rigorously screened healthy subjects (control). A statistically significant distinction between control and diabetic subjects was provided by the standard deviation and the higher moments of the distributions (skewness, and kurtosis) with respect to the median. To compare IBI and SBP for different populations, we define a parameter, α, that combines the variability of the heart rate and the blood pressure, as the ratio of the radius of the moments for IBI and the same radius for SBP. As diabetes evolves, α decreases, standard deviation of the IBI detrended signal diminishes (heart rate signal becomes more "rigid"), skewness with respect to the median approaches zero (signal fluctuations gain symmetry), and kurtosis increases (fluctuations concentrate around the median). Diabetes produces not only a rigid heart rate, but also increases symmetry and has leptokurtic distributions. SBP time series exhibit the most variable behavior for recently diagnosed DM with platykurtic distributions. Under controlled breathing, SBP has symmetric distributions for DM patients, while control subjects have non-zero skewness. This may be due to a progressive decrease of parasympathetic and sympathetic activity to the heart and blood vessels as diabetes evolves.

From supine to standing: in vivo segregation of myogenic and baroreceptor vasoconstriction in humans.

Myogenic vascular response is a form of systemic and regional vasoconstriction produced increasing the intra-arterial pressure by gravity. Here, the vasoconstriction due to the myogenic response, induced by the gravitational action in a dependent limb, is separated from that caused by the baroreceptor reflex. Regional changes of skin blood flow (SBF), total blood volume of the finger (TBVF), pulse pressure (PP), heart rate (HR), systolic, and diastolic blood pressure (BP) were analyzed in 10 healthy young subjects in supine and upright positions. By lowering the arm in supine position, SBF decreased compared to its basal measurement, PR increased, and PP contracted, indicating arterial vasoconstriction that rise BP TBVF increased, demonstrating an increment in venous volume. HR did not change, reflecting no action of the baroreceptor reflex. In upright position with lowered arm, there was an additional increase in BP variables, demonstrating vasoconstriction. Moreover, BP and HR showed oscillations at 0.1 Hz reflecting the entrance of the baroreceptor reflex. The action of gravity in a dependent limb in supine position induces a regional vasoconstriction and an increase of BP due to activation of the myogenic response, while the baroreceptor reflex or other neural factors do not appear to operate. In the upright position with the arm dependent, there is a further increase in regional vasoconstriction and BP with reciprocal changes in HR, indicating the entrance of the baroreceptor superimposed to the myogenic response. This study demonstrates that the myogenic and baroreceptor vasoconstriction can be separated in vivo.

Heart Rate and Systolic Blood Pressure Variability on Recently Diagnosed Diabetics / Variabilidade da Frequência Cardíaca e da Pressão Arterial Sistólica em Diabéticos com Diagnóstico Recente

Background:Diabetes affects approximately 250 million people in the world. Cardiovascular autonomic neuropathy is a common complication of diabetes that leads to severe postural hypotension, exercise intolerance, and increased incidence of silent myocardial infarction.Objective:To determine the variability of heart rate (HR) and systolic blood pressure (SBP) in recently diagnosed diabetic patients.Methods:The study included 30 patients with a diagnosis of type 2 diabetes of less than 2 years and 30 healthy controls. We used a Finapres® device to measure during five minutes beat-to-beat HR and blood pressure in three experimental conditions: supine position, standing position, and rhythmic breathing at 0.1 Hz. The results were analyzed in the time and frequency domains.Results:In the HR analysis, statistically significant differences were found in the time domain, specifically on short-term values such as standard deviation of NN intervals (SDNN), root mean square of successive differences (RMSSD), and number of pairs of successive NNs that differ by more than 50 ms (pNN50). In the BP analysis, there were no significant differences, but there was a sympathetic dominance in all three conditions. The baroreflex sensitivity (BRS) decreased in patients with early diabetes compared with healthy subjects during the standing maneuver.Conclusions:There is a decrease in HR variability in patients with early type 2 diabetes. No changes were observed in the BP analysis in the supine position, but there were changes in BRS with the standing maneuver, probably due to sympathetic hyperactivity.

Fundamento:O diabetes afeta aproximadamente 250 milhões de pessoas no mundo. A neuropatia autonômica cardiovascular é uma complicação comum do diabetes que leva à hipotensão postural grave, intolerância ao exercício e aumento na incidência de infarto do miocárdio silencioso.Objetivo:Determinar a variabilidade da frequência cardíaca (FC) e da pressão arterial sistólica (PAS) em pacientes diabéticos com diagnóstico recente.Métodos:O estudo incluiu 30 pacientes com diabetes tipo 2 diagnosticado há menos de 2 anos e 30 controles saudáveis. Nós utilizamos o dispositivo Finapres® para medir durante cinco minutos a FC batimento-a-batimento e a pressão arterial (PA) em três condições experimentais: posição supina, em pé e durante respiração rítmica na frequência de 0,1 Hz. Os resultados foram analisados nos domínios do tempo e da frequência.Resultados:Em relação à FC, foram encontradas diferenças estatisticamente significativas nos valores da análise do domínio do tempo, especificamente em valores determinados a curto prazo, tais como o desvio-padrão dos intervalos NN (DPNN), a raiz quadrada da média das diferenças sucessivas (RQMDS) para a FC e o número de pares de NNs sucessivos que diferem em mais de 50 ms (pNN50). Não houve diferença significativa na análise da PA, mas houve uma dominância simpática nas três condições. A sensibilidade do barorreflexo (SBR) esteve diminuída em pacientes com diabetes de início recente, em comparação aos indivíduos saudáveis durante execução da manobra na posição ortostática.Conclusões:Há uma diminuição na variabilidade da FC em pacientes com diabetes tipo 2 de início recente. Não foram observadas alterações na análise da PA na posição supina, mas a SBR apresentou mudança com a manobra em pé provavelmente causada por hiperatividade simpática.

Heart rate and systolic blood pressure variability on recently diagnosed diabetics.

BACKGROUND: Diabetes affects approximately 250 million people in the world. Cardiovascular autonomic neuropathy is a common complication of diabetes that leads to severe postural hypotension, exercise intolerance, and increased incidence of silent myocardial infarction. OBJECTIVE: To determine the variability of heart rate (HR) and systolic blood pressure (SBP) in recently diagnosed diabetic patients. METHODS: The study included 30 patients with a diagnosis of type 2 diabetes of less than 2 years and 30 healthy controls. We used a Finapres® device to measure during five minutes beat-to-beat HR and blood pressure in three experimental conditions: supine position, standing position, and rhythmic breathing at 0.1 Hz. The results were analyzed in the time and frequency domains. RESULTS: In the HR analysis, statistically significant differences were found in the time domain, specifically on short-term values such as standard deviation of NN intervals (SDNN), root mean square of successive differences (RMSSD), and number of pairs of successive NNs that differ by more than 50 ms (pNN50). In the BP analysis, there were no significant differences, but there was a sympathetic dominance in all three conditions. The baroreflex sensitivity (BRS) decreased in patients with early diabetes compared with healthy subjects during the standing maneuver. CONCLUSIONS: There is a decrease in HR variability in patients with early type 2 diabetes. No changes were observed in the BP analysis in the supine position, but there were changes in BRS with the standing maneuver, probably due to sympathetic hyperactivity.

Cardiovascular variability in Mexican patients with Parkinson's disease.

UNLABELLED: Cardiovascular variability (CVV) has been evaluated in patients with Parkinson's disease (PD) in other countries and exhibit ethnic differences. OBJECTIVE: We investigated heart rate variability (HRV) and blood pressure variability (BPV) in Mexican patients with PD. METHOD: We further compared HRV and BPV between this group and young healthy controls (YHC) in order to estimate, for the first time in our country, the magnitude of the difference. Twenty patients were examined. Time- and frequency-domain CVV parameters were studied during supine rest (SR), active standing (AS) and controlled breathing. These measurements were compared to those of 20 YHC. RESULTS: In the three conditions tested, our study showed a decrease in almost all HRV parameters in PD patients; on the contrary, decreased BPV parameters were found less frequently and only during SR and AS. CONCLUSION: Our results indicate that HRV is impaired in PD. Some BPV parameters are also diminished.

Cardiovascular variability in Mexican patients with Parkinson's disease / Variabilidade cardiovascular em pacientes mexicanos com doença de Parkinson

Cardiovascular variability (CVV) has been evaluated in patients with Parkinson's disease (PD) in other countries and exhibit ethnic differences. Objective We investigated heart rate variability (HRV) and blood pressure variability (BPV) in Mexican patients with PD. Method We further compared HRV and BPV between this group and young healthy controls (YHC) in order to estimate, for the first time in our country, the magnitude of the difference. Twenty patients were examined. Time- and frequency-domain CVV parameters were studied during supine rest (SR), active standing (AS) and controlled breathing. These measurements were compared to those of 20 YHC. Results In the three conditions tested, our study showed a decrease in almost all HRV parameters in PD patients; on the contrary, decreased BPV parameters were found less frequently and only during SR and AS. Conclusion Our results indicate that HRV is impaired in PD. Some BPV parameters are also diminished. .

A variabilidade cardiovascular (VCV) tem sido avaliada em doentes parkinsonianos em vários países e apresenta diferenças étnicas. Objetivo Investigar a variabilidade da frequência cardíaca (VFC) e a variabilidade da pressão arterial (VPA) em doentes parkinsonianos mexicanos. Método Comparamos VFC e VPA entre o grupo de estudo e controles jovens (CJ), a fim de estimar a magnitude da diferença. CVV foi estudada no domínio do tempo e da frequência durante repouso supino (RS), ortostase ativa (OA) e respiração controlada. Estas medições foram comparadas com aquelas de 20 CJ. Resultados Nosso estudo mostrou diminuição em quase todos os parâmetros da VFC em doentes parkinsonianos. A diminuição dos parâmetros da VPA foi encontrada com menos frequência. Conclusão Nossos resultados indicam que a VFC é prejudicada na doença de Parkinson. Alguns parâmetros do VPA também são reduzidos. .