O efeito da indução miofascial suboccipital no sistema nervoso autónomo

Projeto de Graduação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Licenciada em FisioterapiaIntrodução: Com a prática baseada na evidência a ser cada vez mais valorizada é premente comprovar a eficácia das técnicas manuais.A modulação do sistema nervoso autónomo (SNA) é cada vez mais importante na prevenção/tratamento de doenças pela manutenção/restabelecimento da homeostasia corporal.Objectivo:Averiguar qual o efeito das técnicas miofasciais no SNA.Métodos:Foram avaliadas as variáveis da variabilidade da frequência cardíaca (VFC) e a pressão arterial (PA) de 30 indivíduos (idade média=23,50±4,02 anos),utilizando um protocolo onde os indivíduos deveriam respirar a um ritmo de 15cpm, durante 15 minutos sendo realizada no grupo experimental(GE) a indução miofascial suboccipital nos 5 minutos intermédios.Resultados:Com a aplicação da técnica obteve-se um aumento do RMSSD e diminuição da frequência cardíaca média no GE, ainda que se verifique uma leve tendência para aumento SDNN, pNN50, HF e diminuição da razão LF/HF.Houve também uma diminuição da PA Sistólica (PAS).Conclusão:As técnicas miofasciais causam o aumento da actividade do sistema nervoso parassimpático(SNP), podendo ser úteis em diversas áreas desde a prevenção de doenças cardiovasculares à intervenção em geriatria/desporto. prove the effect of manual techniques.Autonomous nervous system (ANS) modulation takes its place as a tool for diseases’ treatment and prevention by maintenance/reestablishment of body homeostasis.Aim:Understand the effect of myofascial techniques on ANS.Methods: Heart rate and blood pressure data from 30 subjects (mean age=23,50±4,02 years-old) were evaluated,using a protocol were they should breath at a pre-determinate rate (15cpm), during 15 minutes.In the experimental group (EG) the technique (suboccipital induction) was performed on the 5 central minutes.Results:With the application of the technique in the EG there was a significant increase of RMSSD and decrease on average HR,with a light tendency to increased SDNN,pNN50,HF and decreased LF/HF ratio.It was also visible a decrease in Systolic BP.Conclusion:Myofascial techniques caused an increase in parasympathetic nervous system,being therefor useful in several areas since heart disease prevention to geriatric/sports intervention

Comparing low frequency heart rate variability and preejection period: Two sides of a different coin.

It has been hypothesized that the ratio of heart rate variability in the low- (LF) and high- (HF) frequency bands may capture variation in cardiac sympathetic control. Here we tested the temporal stability of the LF/HF ratio in 24-h ambulatory recordings and compared this ratio to the preejection period (PEP), an established measure of cardiac sympathetic control. Good temporal stability was found across a period of 3.3 years (.46<r<.78), but the LF/HF ratio did not show the expected negative correlation to PEP, either between or within subjects. We conclude that the evidence to support the LF/HF ratio as a potential marker of cardiac sympathetic control in epidemiology-scaled research is currently insufficient. Copyright © 2008 Society for Psychophysiological Research

Prolonged decrease in heart rate variability after elective hip arthroplasty

The pattern of postoperative heart rate variability may provide insight into the response of the autonomic nervous system to anaesthesia and surgery. We have obtained spectral (fast Fourier transform) and non-spectral indices of heart rate variability from electrocardiographic recordings, sampled during continuous perioperative Holter monitoring in 15 otherwise healthy patients with an uncomplicated postoperative course, undergoing elective hip arthroplasty with either spinal or general anaesthesia. In both groups, total spectral energy (0.01-1 Hz), low-frequency spectral energy (0.01-0.15 Hz) and high-frequency spectral energy (0.15-0.40 Hz) decreased after surgery to 32% (95% confidence interval (Cl) 10.5; P <0.01), 29% (95% Cl 12.5; P <0.07; and 33% (95% Cl 12.5; P <0.01) of their preoperative values, respectively, and these indices remained suppressed for up to 5 days. Non-spectral indices decreased to a similar extent. These findings indicate a substantial and prolonged postoperative decrease in both parasympathetic and sympathetic influence on the sinus nod

Temporal profile and mechanisms of the prompt sympathoexcitation following coronary ligation in Wistar rats

Our aim was to assess the timing and mechanisms of the sympathoexcitation that occurs immediately after coronary ligation. We recorded thoracic sympathetic (tSNA) and phrenic activities, heart rate (HR) and perfusion pressure in Wistar rats subjected to either ligation of the left anterior descending coronary artery (LAD) or Sham operated in the working heart-brainstem preparation. Thirty minutes after LAD ligation, tSNA had increased (basal: 2.5±0.2 µV, 30 min: 3.5±0.3 µV), being even higher at 60 min (5.2±0.5 µV, P<0.01); while no change was observed in Sham animals. HR increased significantly 45 min after LAD (P<0.01). Sixty minutes after LAD ligation, there was: (i) an augmented peripheral chemoreflex - greater sympathoexcitatory response (50, 45 and 27% of increase to 25, 50 and 75 µL injections of NaCN 0.03%, respectively, when compared to Sham, P<0.01); (ii) an elevated pressor response (32±1 versus 23±1 mmHg in Sham, P<0.01) and a reduced baroreflex sympathetic gain (1.3±0.1 versus Sham 2.0±0.1%.mmHg-1, P<0.01) to phenylephrine injection; (iii) an elevated cardiac sympathetic tone (ΔHR after atenolol: -108±8 versus -82±7 bpm in Sham, P<0.05). In contrast, no changes were observed in cardiac vagal tone and bradycardic response to both baroreflex and chemoreflex between LAD and Sham groups. The immediate sympathoexcitatory response in LAD rats was dependent on an excitatory spinal sympathetic cardiocardiac reflex, whereas at 3 h an angiotensin II type 1 receptor mechanism was essential since Losartan curbed the response by 34% relative to LAD rats administered saline (P<0.05). A spinal reflex appears key to the immediate sympathoexcitatory response after coronary ligation. Therefore, the sympathoexcitatory response seems to be maintained by an angiotensinergic mechanism and concomitant augmentation of sympathoexcitatory reflexes

Is the algorithm used to process heart rate variability data clinically relevant? Analysis in male adolescents

OBJECTIVE: To analyze whether the algorithm used for the heart rate variability assessment (fast Fourier transform versus autoregressive methods) influenced its association with cardiovascular risk factors in male adolescents. METHODS: This cross-sectional study included 1,152 male adolescents (aged 14 to 19 years). The low frequency, high frequency components (absolute numbers and normalized units), low frequency/high frequency ratio, and total power of heart rate variability parameters were obtained using the fast Fourier transform and autoregressive methods, while the adolescents were resting in a supine position. RESULTS: All heart rate variability parameters calculated from both methods were different (p<0.05). However, a low effect size (<0.1) was found for all parameters. The intra-class correlation between methods ranged from 0.96 to 0.99, whereas the variation coefficient ranged from 7.4 to 14.8%. Furthermore, waist circumference was negatively associated with high frequency, and positively associated with low frequency and sympatovagal balance (p<0.001 for both fast Fourier transform and autoregressive methods in all associations). Systolic blood pressure was negatively associated with total power and high frequency, whereas it was positively associated with low frequency and sympatovagal balance (p<0.001 for both fast Fourier transform and autoregressive methods in all associations). Body mass index was negatively associated with high frequency, while it was positively associated with low frequency and sympatovagal balance (p values ranged from <0.001 to 0.007). CONCLUSION: There are significant differences in heart rate variability parameters obtained with the fast Fourier transform and autoregressive methods in male adolescent; however, these differences are not clinically significant. OBJETIVO: Analisar se o algoritmo usado para avaliação da variabilidade da frequência cardíaca (transformada rápida de Fourier versus autoregressivo) influencia em sua associação com fatores de risco cardiovascular adolescentes do gênero masculino. MÉTODOS: Estudo transversal, que incluiu 1.152 adolescentes do gênero masculino (14 a 19 anos). Componentes de baixa e alta frequência (absolutos e unidades normalizadas), razão componente de baixa frequência/componente de alta frequência e poder total da variabilidade da frequência cardíaca foram obtidos em repouso, na posição supina, usando os métodos transformada rápida de Fourier e autorregressivo. RESULTADOS: Todos os parâmetros da variabilidade da frequência cardíaca para ambos os métodos foram diferentes (p<0,05). Entretanto, um pequeno tamanho do efeito (<0,1) foi observado para todos os parâmetros. Os coeficientes de correlação intraclasse entre os métodos variaram de 0,96 a 0,99, enquanto os coeficientes de variação foram de 7,4 a 14,8%. A circunferência abdominal foi negativamente associada com o componente de alta frequência, e positivamente associada com o componente de baixa frequência e o balanço simpatovagal (p<0,001 para a transformada rápida de Fourier e o autorregressivo em todas as associações). A pressão arterial sistólica foi negativamente associada com o poder total e o componente de alta frequência, enquanto foi positivamente associada com o componente de baixa frequência e o balanço simpatovagal (p<0,001 para a transformada rápida de Fourier e o autorregressivo em todas as associações). O índice de massa corporal foi negativamente associado com o componente de alta frequência, enquanto foi positivamente associado com o componente de baixa frequência e o balanço simpatovagal (valores de p variando de <0,001 a 0,007). CONCLUSÃO: Houve diferenças significantes nos parâmetros da variabilidade da frequência cardíaca obtidos com os métodos transformada rápida de Fourier e autorregressivo em adolescentes masculinos, mas essas diferenças não foram clinicamente significativas

Prolonged head down bed rest-induced inactivity impairs tonic autonomic regulation while sparing oscillatory cardiovascular rhythms in healthy humans.

Background. Physical inactivity represents a major risk for cardiovascular disorders, such as hypertension, myocardial infarction or sudden death; however, underlying mechanisms are not clearly elucidated. Clinical and epidemiological investigations suggest, beyond molecular changes, the possibility of an induced impairment in autonomic cardiovascular regulation. However, this hypothesis has not been tested directly. Methods. Accordingly, we planned a study with noninvasive, minimally intrusive, techniques on healthy volunteers. Participants were maintained for 90 days strictly in bed, 24 h a day, in head-down (S6-) position (HDBR). Physical activity was thus virtually abolished for the entire period of HDBR. We examined efferent muscle sympathetic nerve activity, as a measure of vascular sympathetic control, baroreceptor reflex sensitivity, heart rate variability (assessing cardiovagal regulation), RR and systolic arterial pressure and low-frequency and high-frequency normalized components (as a window on central oscillatory regulation). Measures. were obtained at rest and during simple maneuvers (moderate handgrip, lower body negative pressure and active standing) to assess potential changes in autonomic cardiovascular responsiveness to standard stimuli and the related oscillatory profiles. Results HDBR transiently reduced muscle sympathetic nerve activity,RR,heart ratevariabilityandbaroreceptor reflex sensitivity late during HDBR or early during the recovery phase. Conversely, oscillatory profiles of RR and systolic arterial pressure variability were maintained throughout. Responsiveness to test stimuli was also largely maintained

Contribution of Autonomic Reflexes to the Hyperadrenergic State in Heart Failure

Heart failure (HF) is a complex syndrome representing the clinical endpoint of many cardiovascular diseases of different etiology. Given its prevalence, incidence and social impact, a better understanding of HF pathophysiology is paramount to implement more effective anti-HF therapies. Based on left ventricle (LV) performance, HF is currently classified as follows: (1) with reduced ejection fraction (HFrEF); (2) with mid-range EF (HFmrEF); and (3) with preserved EF (HFpEF). A central tenet of HFrEF pathophysiology is adrenergic hyperactivity, featuring increased sympathetic nerve discharge and a progressive loss of rhythmical sympathetic oscillations. The role of reflex mechanisms in sustaining adrenergic abnormalities during HFrEF is increasingly well appreciated and delineated. However, the same cannot be said for patients affected by HFpEF or HFmrEF, whom also present with autonomic dysfunction. Neural mechanisms of cardiovascular regulation act as "controller units," detecting and adjusting for changes in arterial blood pressure, blood volume, and arterial concentrations of oxygen, carbon dioxide and pH, as well as for humoral factors eventually released after myocardial (or other tissue) ischemia. They do so on a beat-to-beat basis. The central dynamic integration of all these afferent signals ensures homeostasis, at rest and during states of physiological or pathophysiological stress. Thus, the net result of information gathered by each controller unit is transmitted by the autonomic branch using two different codes: intensity and rhythm of sympathetic discharges. The main scope of the present article is to (i) review the key neural mechanisms involved in cardiovascular regulation; (ii) discuss how their dysfunction accounts for the hyperadrenergic state present in certain forms of HF; and (iii) summarize how sympathetic efferent traffic reveal central integration among autonomic mechanisms under physiological and pathological conditions, with a special emphasis on pathophysiological characteristics of HF

Autonomic pain responses during sleep: a study of heart rate variability

The autonomic nervous system (ANS) reacts to nociceptive stimulation during sleep, but whether this reaction is contingent to cortical arousal, and whether one of the autonomic arms (sympathetic/parasympathetic) predominates over the other remains unknown. We assessed ANS reactivity to nociceptive stimulation during all sleep stages through heart rate variability, and correlated the results with the presence of cortical arousal measured in concomitant 32-channel EEG. Fourteen healthy volunteers underwent whole-night polysomnography during which nociceptive laser stimuli were applied over the hand. RR intervals (RR) and spectral analysis by wavelet transform were performed to assess parasympathetic (HF(WV)) and sympathetic (LF(WV) and LF(WV)/HF(WV) ratio) reactivity. During all sleep stages, RR significantly decreased in reaction to nociceptive stimulations, reaching a level similar to that of wakefulness, at the 3rd beat post-stimulus and returning to baseline after seven beats. This RR decrease was associated with an increase in sympathetic LF(WV) and LF(WV)/HF(WV) ratio without any parasympathetic HF(WV) change. Albeit RR decrease existed even in the absence of arousals, it was significantly higher when an arousal followed the noxious stimulus. These results suggest that the sympathetic-dependent cardiac activation induced by nociceptive stimuli is modulated by a sleep dependent phenomenon related to cortical activation and not by sleep itself, since it reaches a same intensity whatever the state of vigilance

Development of an Adroid application to support the Holter monitoring system

В роботі розглянуті питання розробки програмного забезпечення для підтримки системи холтерівського моніторування, яке орієнтоване на застосування пристроїв, на базі операційної систему Android. На основі існуючих методів цифрової обробки даних розроблено програмний додаток, який дозволяє проводити моніторування стану серцево-судинної системи користувача в режимі реального часу та наступною відправкою даних безпосередньо до лікаря-фахівця в зручному для аналізу форматі. Запропоновано метод обробки даних за допомогою алгоритму, в основі якого використано шаблон, складений з метасимволів регулярних виразів, який забезпечує швидке і точне просіювання отриманих даних. В результаті роботи алгоритму формується бінарний файл, який містить тільки необхідні дані для подальшого аналізу. На перших етапах програмний додаток, встановлений на Android пристрої, виконує первинний аналіз файлу і розбиває дані на фрагменти, які відповідають часовим проміжкам тривалістю шістдесят хвилин кожний. Таким чином, протягом доби формується двадцять чотири фрагмента даних, на основі кожного з яких створюються графіки, що ілюструють роботу серцево-судинної системи пацієнта, які користувач має можливість переглянути. При виникненні критичних показників в роботі серцево-судинної системи, програмний додаток автоматично викликає швидку допомогу та відправляє лікарю дані за останні дві доби у форматі крапкових графіків, оскільки досвід практикуючих лікарів показав, що саме такі графіки є найбільш наочними та інформативними. Також лікар має можливість отримати доступ до даних холтерівського моніторування серцево-судинної системи користувача в будь-який момент, використавши термінальну частину програми на своєму Android пристрої.This paper examines the process of software development to implement the system, working on the devices with Android operating system, which is based on Holter monitoring. Application software has been developed using existing methods of digital data processing, that provides the possibility of real-time monitoring of the user's cardiovascular system with subsequent data transfer directly to a specialist doctor in a format , convenient for data analysis. There was proposed an algorithm for processing data, which is based on a template made up of regular expression metacharacters, that provides fast and accurate sifting of the received data. Binary file that is formed as a result of the algorithm work contains the nec essary data for subsequent analysis. At the first stages, the software application installed on the Android device performs the initial analysis of the file and breaks t he data into fragments that correspond to time periods of sixty minutes. Thus, twentyfour pieces of data are formed during the day. Based on this data created application builds graphs that illustrate the work of the patient's cardiovascular system, which the user can view. If critic al indicators arise in the work of the cardiovascular system, the software application automatically calls an ambulance and sends to the attending physician data for the last forty-eight hours in the format of scatter plots, as the experience of practicing physicians has shown that such plots are the most visual and informative. Also, the attending physician has the opportunity to access the data of Holter monitoring of the user's cardiovascular system at any time, using the te rminal part of the application on his Android device