Estudio de variabilidad de la frecuencia cardiaca en pacientes con sospecha de fallas autonómicas. Utilización del Holter y el Diagrama de Poincare

El estudio de la regularidad de la Frecuencia Cardiaca, a través del Holter de 24 horas se hace desde la década de los años 60 y es bastante efectivo. Sin embargo, desde los años noventa comenzaron a efectuarse estudios cortos de Holter en pacientes sospechados de tener fallas autonómicas de control de la frecuencia cardiaca, especialmente en pacientes con comorbilidades tales como Hipertensión, Diabetes Mellitus, Aterosclerosis etc. De aquí la importancia de realizar un test de Holter de diez minutos, divididos en dos tiempos de 5 minutos, primero en decúbito dorsal y luego en bipedestación, especialmente en pacientes de más de cincuenta años o con comorbilidades presentes. Los resultados se presentan luego en gráficos de Poincare, que incluye el programa operativo del dispositivo, que permite un vistazo de la elipse con sus dos ejes, que representan las acciones simpáticas y parasimpáticas sobre la frecuencia cardiaca. Una variabilidad anormal de la frecuencia cardiaca debe ser luego estudiada más profundamente a fin de reafirmar el diagnóstico y ulteriores pasos en el tratamiento.

The variability of Cardiac Frequency is a valuable monitor of the autonomic function and is currently used as tool for study of changes of regularity through Holter 24 hours. From nighties, several researchers have been oriented to stablish relationship between VCF and autonomic failure, especially in patients with comorbidities, such as Hypertension, Diabetes Mellitus, atherosclerosis etc. Actually is well known that a lost or VCF or a minor variability, even in short traces of Holter in 10 minutes, means an autonomic failure, of baroreflex and quimioreflex resources. Hence, the importance of performing test of ten minutes Holter, five in decubitus position and five in standing, to patients of more than fifty years old, or less if comorbidities are presents, to design a Poincare diagram, which is special to indicate in quick view the prevalence of Sympathetic o Vagal action on cardiac frequency; that conduces to a more deep study of Autonomic failure, such tilt test, extended holter of 24 hours, and others medicals images resources.

Non-linear analysis of heart rate variability during deep breathing at 0.1 Hz frequency

Background: Heart rate variability (HRV) analysis is an important tool to assess the cardiac autonomic regulation in health and disease. Time-domain and frequency-domain analyses are linear methods that are traditionally used for HRV analysis. Application of non-linear methods in HRV analysis has been shown to provide additional information and has been found to be useful in predicting complications and mortality in cardiovascular disease conditions. HRV analysis during deep breathing is commonly used to assess the integrity and extent of the parasympathetic control of the heart. Aim and Objectives: This study aims to analyze the HRV during deep breathing at 0.1 Hz frequency, 6 breaths/minute using non-linear methods and to see whether they correlate with the time-domain measures of HRV. Materials and Methods: Twelve healthy volunteers performed deep slow breathing at 0.1 Hz frequency for 5 min following recorded prompts. In the time domain, mean heart rate (MHR), SDNN, RMSSD, and pNN50 during baseline and deep breathing were measured. In the non-linear domain, approximate entropy (AppEn), sample entropy (SampEn), and detrended fluctuation analysis DFA (?1) were calculated. The quantitative measures of the Poincare plot, namely, SD1, SD2, and SD2/SD1, which are known to provide linear information, were also estimated. Wilcoxon’s signed-rank test was used to compare the baseline parameters with those of deep breathing. Spearman’s correlation was used to assess the correlation between the parameters obtained from the different methods. Results: There was no significant change in the MHR, RMSSD, pNN50, and SD1 during 0.1 Hz deep breathing while SDNN, SD2, SD2/SD1, and DFA?1 showed a significant increase. Furthermore, 0.1 Hz breathing decreased the AppEn and SampEn measures of HRV. There was a strong correlation among SDNN, RMSSD, pNN50, SD1, SD2, SD2/SD1, and DFA?1, but there was no correlation between any of the above measures and the non-linear measures AppEn and SampEn. Conclusion: While the non-linear measure DFA?1 correlates well with time domain measures of HRV and the quantitative measures of the Poincare plot during 0.1 Hz breathing, AppEn and SampEn do not show such correlation. Instead, they decrease significantly when breathing is voluntarily controlled at 6 breaths/min.

Classification of Fetal Heart Rate Based on Poincare Plot and LSTM / 中国医疗器械杂志

Fetal heart rate plays an essential role in maternal and fetal monitoring and fetal health detection. In this study, a method based on Poincare Plot and LSTM is proposed to realize the high performance classification of abnormal fetal heart rate. Firstly, the original fetal heart rate signal of CTU-UHB database is preprocessed via interpolation, then the sequential fetal heart rate signal is converted into Poincare Plot to obtain nonlinear characteristics of the signals, and then SquenzeNet is used to extract the features of Poincare Plot. Finally, the features extracted by SqueezeNet are classified by LSTM. And the accuracy, the true positive rate and the false positive rate are 98.00%, 100.00%, 92.30% respectively on 2 000 test set data. Compared with the traditional fetal heart rate classification method, all respects are improved. The method proposed in this study has good performance in CTU-UHB fetal monitoring database and has certain practical value in the clinical diagnosis of auxiliary fetal heart rate detection.

Design and Implementation of Portable Abnormal ECG Signal Analysis Instrument Based on Feature Classifcation / 中国医疗器械杂志

OBJECTIVES@#To collect and analyze the ECG signal in real time, the analog filter and the signal amplifier were used to construct the abnormal signal acquisition and classification system.@*METHODS@#The ARM10E processor was used to detect the signal shape and QRS complex wave. Based on the Poincare support vector machine, the feature set was extracted from the training data set to construct the heart disease classifier, and the clinical classification model was given.@*RESULTS@#The device effectively reduces computational complexity, improves processor speed, real-time acquisition and diagnoses heart disease.@*CONCLUSIONS@#Portable ECG devices can capture suspected waveforms of abnormal signals, establish and evaluate high quality signals, reduce patient on-line waiting time, and facilitate early diagnosis and recognition of heart disease.

Effects of vagotomy on cardiovascular and heart rate variability alterations following chronic normobaric hypoxia in adult rabbits

BACKGROUND: chronic hypoxia increases basal ventilation and pulmonary vascular resistance, with variable changes in arterial blood pressure and heart rate, but it's impact on heart rate variability and autonomic regulation have been less well examined. We studied changes in arterial blood pressure, heart rate and heart rate variability (HRV) in rabbits subjected to chronic normobaric hypoxia (CNH; PB ~ 719 mmHg; FIO2 ~ 9.2%) for 14 days and assess the effect of autonomic control by acute bilateral vagal denervation. RESULTS: exposure to CNH stalled animal weight gain and increased the hematocrit, without affecting heart rate or arterial blood pressure. Nevertheless, Poincaré plots of the electrocardiographic R-R intervals showed a reduced distribution parallel to the line of identity, which interpreted as reduced long-term HRV. In the frequency domain, CNH reduced the very-low- (< 0.2 Hz) and high-frequency components (> 0.8 Hz) of the R-R spectrograms and produced a prominent component in the low-frequency component (0.2-0.5 Hz) of the power spectrum. In control and CNH exposed rabbits, bilateral vagotomy had no apparent effect on the short- and long-term HRV in the Poincaré plots. However, bilateral vagotomy differentially affected higher-frequency components (> 0.8 Hz); reducing it in control animals without modifying it in CNH-exposed rabbits. CONCLUSIONS: These results suggest that CNH exposure shifts the autonomic balance of heart rate towards a sympathetic predominance without modifying resting heart rate or arterial blood pressure.

Influence of exercise modality on agreement between gas exchange and heart rate variability thresholds

The main purpose of this study was to investigate the level of agreement between the gas exchange threshold (GET) and heart rate variability threshold (HRVT) during maximal cardiopulmonary exercise testing (CPET) using three different exercise modalities. A further aim was to establish whether there was a 1:1 relationship between the percentage heart rate reserve (%HRR) and percentage oxygen uptake reserve ( % V ˙ O 2  R ) at intensities corresponding to GET and HRVT. Sixteen apparently healthy men 17 to 28 years of age performed three maximal CPETs (cycling, walking, and running). Mean heart rate and V ˙ O 2 at GET and HRVT were 16 bpm (P<0.001) and 5.2 mL·kg-1·min-1 (P=0.001) higher in running than cycling, but no significant differences were observed between running and walking, or cycling and walking (P>0.05). There was a strong relationship between GET and HRVT, with R2 ranging from 0.69 to 0.90. A 1:1 relationship between %HRR and % V ˙ O 2  R was not observed at GET and HRVT. The %HRR was higher during cycling (GET mean difference=7%; HRVT mean difference=11%; both P<0.001), walking (GET mean difference=13%; HRVT mean difference=13%; both P<0.001), or running (GET mean difference=11%; HRVT mean difference=10%; both P<0.001). Therefore, using HRVT to prescribe aerobic exercise intensity appears to be valid. However, to assume a 1:1 relationship between %HRR and % V ˙ O 2  R at HRVT would probably result in overestimation of the energy expenditure during the bout of exercise.

Group behaviour in physical, chemical and biological systems.

Groups exhibit properties that either are not perceived to exist, or perhaps cannot exist, at the individual level. Such ‘emergent’ properties depend on how individuals interact, both among themselves and with their surroundings. The world of everyday objects consists of material entities. These are, ultimately, groups of elementary particles that organize themselves into atoms and molecules, occupy space, and so on. It turns out that an explanation of even the most commonplace features of this world requires relativistic quantum field theory and the fact that Planck’s constant is discrete, not zero. Groups of molecules in solution, in particular polymers (‘sols’), can form viscous clusters that behave like elastic solids (‘gels’). Sol-gel transitions are examples of cooperative phenomena. Their occurrence is explained by modelling the statistics of inter-unit interactions: the likelihood of either state varies sharply as a critical parameter crosses a threshold value. Group behaviour among cells or organisms is often heritable and therefore can evolve. This permits an additional, typically biological, explanation for it in terms of reproductive advantage, whether of the individual or of the group. There is no general agreement on the appropriate explanatory framework for understanding group-level phenomena in biology.

Os psicanalistas sabem debater? / Do psychoanalysts know how to debate? / Los psicoanalistas saben debatir?

O autor discute neste trabalho as condições que dificultam um debate, e menciona historicamente alguns debates no campo da psicanálise que foram importantes, embora nem sempre tão frutíferos quanto poderiam ter sido.

En este trabajo, el autor discute ciertas condiciones que dificultan un buen debate y menciona históricamente algunos debates en el campo del psicoanálisis que fueron importantes, aunque no necesariamente tan fructíferos como podrían haber sido.

In this paper, the author discusses the conditions that hinder a debate and mentions some historical debates on the psychoanalysis field that were important though not always as fruitful as they could have been

Poincare Plot of Heart Rate Variability An Approach Towards Explaining the Cardiovascular Autonomic Function in Obesity.

Obesity has been shown to affect cardiovascular function. Heart rate variability (HRV) has been an accepted method of measuring cardiovascular autonomic function. The aim of the study is to evaluate the impact of obesity on HRV using Poincaré plot (POP) analysis. A finding of sympathovagal imbalance in pre-obese adults in respiratory sinus arrhythmia (RSA) could provide important diagnostic information about early subclinical autonomic dysfunction in obesity. Thirty one obese (BMI 26.84±2.47) adult males (25.42±7.86 years) were compared with 31 normal subjects (25.38±4.61 years). In all participants, anthropometric and blood pressure (BP) measurements were performed. After rest at supine position for 5 minutes, they were asked to do control deep breathing for 1 minute. HRV was measured in terms of POP analysis. Differences in Resting heart rate (RHR) (P≤0.025), Pulse pressure (PP) (P≤0.048), SD1 (P≤0.042) and SD2 (P≤0.039) of the POP between the two groups were significant. Correlation between Body mass index (BMI) and (PP) (p=0.19); SD1 (p=0.47) and SD2 (p=0.39) of the POP were significant in obese groups. Obesity is related to sympathovagal imbalance characterized by depressed parasympathetic tone and increased sympathetic activity. Nonlinear methods like POP permit simple assessment of autonomic function, despite measuring different aspects of HRV.

Tortuosidade e conectividade da rede trabecular do rádio distal a partir de imagens microtomográficas / Trabecular network tortuosity and connectivity of distal radius from microtomographic images

A osteoporose é uma doença que causa perda de massa óssea e deterioração da estrutura trabecular. A rede formada pelo osso trabecular é muito importante para estabelecer a competência mecânica do esqueleto. Estudos mostram que a microarquitetura trabecular pode elevar a predição do risco de fratura para cerca de 90 por cento , por isso a sua investigação é de grande interesse da comunidade científica. Vários parâmetros estão relacionados à competência mecânica da estrutura óssea, entretanto, a tortuosidade trabecular ainda não foi seriamente levada em consideração e sua contribuição é desconhecida. Neste trabalho, o enfoque está direcionado à estimativa da tortuosidade trabecular e sua correlação com a conectividade, através da característica de Euler-Poincaré, para amostras do osso rádio distal in  vitro, a partir de imagens de microtomografia computadorizada. Um método para estimar a tortuosidade do volume trabecular é apresentado e a tortuosidade é computada para os dois sentidos das três direções do volume. Os resultados apresentam valores distintos da tortuosidade dependendo da qualidade da rede trabecular e uma correlação positiva (r  =   0,64) com a característica de Euler-Poincaré; além disso, observa-se que a tortuosidade busca alinhar-se nas direções de maiores tensões e compressões imprimidas à rede trabecular. Tais resultados evidenciam a importância da tortuosidade como parâmetro estrutural da rede trabecular.

Osteoporosis is disease causing bone mass loss and deterioration of the trabecular structure. The trabecular network is very important to establish the mechanical competence of the skeleton. It is known that the trabecular microarchitecture can improve the fracture risk prediction up to 90 percent , for this reason the trabecular bone investigation has become of great interest for the scientific community. Several parameters provide structural details of the bone mechanical competence, however, the trabecular network tortuosity has not been seriously taken into account yet and its contribution is unknown. This paper directs attention to the trabecular tortuosity estimation and its correlation to the connectivity, through Euler-Poincaré characteristic, from in  vitro distal radius bone samples by micro-computed tomographic images. A method to estimate the trabecular bone tortuosity is presented and its value is computed for both directions of the three volume axis. The results indicate that the trabecular tortuosity depends on the trabecular network quality and a positive correlation (r  = 0.64) with the Euler-Poincaré characteristic. Inasmuch, it has been observed that the tortuosity tends to get aligned in the direction of main stress imposed on trabecular bone network. These results support the tortuosity as an important structural parameter.

Característica de Euler-Poincaré aplicada para identificar baixa densidade óssea a partir de imagens tomográficas de vértebras / The Euler-Poincaré characteristic applied to identify low bone density from vertebral tomographic images

A densidade mineral óssea (DMO) é o exame padrão-ouro para o diagnóstico da osteoporose. No entanto, sabe-se que apenas essa medida não é suficiente para identificar completamente a fragilidade óssea e o conseqüente risco de fratura, tornando-se necessário a investigação da estrutura óssea. OBJETIVOS: Avaliar se a característica de Euler-Poincaré (CEP) para analisar a conectividade do osso trabecular poderia fornecer um suporte adicional na identificação da deterioração da estrutura óssea. MATERIAIS E MÉTODOS: Analisou-se um conjunto de imagens formando disectors, obtidas da tomografia computadorizada de vértebras lombares, a partir dos quais foi estimada a característica Euler-Poincarè.(CEP). Para lidar com o processamento de imagens dos disectors, foi desenvolvido um programa de computador usando o GTK+ para MS-Windows. Os resultados foram comparados com a DMO. RESULTADOS: Verificou-se que a medida da CEP está correlacionada com os resultados obtidos por meio da DMO para as vértebras lombares. Ficou demonstrado também que a área de conectividade das trabéculas que é propagada ao longo dos disectors corrobora para assegurar que os resultados da CEP sejam consistentes com a medida da DMO. CONCLUSÕES: A aplicação da CEP na análise das tomografias vertebrais poderá vir a se constituir num método para avaliar a estrutura óssea trabecular, e sua correlação com a resistência mecânica do osso, sendo necessários porém mais estudos para confirmar esses dados.

The bone mineral density (BMD) is the gold standard test for the diagnosis of osteoporosis. Nevertheless, it is known that only this measurement is not sufficient to completely identify bone fragility and the consequent risk of fracture, becoming necessary the investigation of the bone structure. OBJECTIVES: Evaluate if the Euler-Poincaré characteristic (EPC) for the analysis of the connectivity of the trabecular bone could supply an additional support in identifying the deterioration of the bone structure. MATERIALS AND METHODS: A group of images forming dissectors were analyzed, obtained from the computerized tomography of the lumbar vertebrae, from which the Euler-Poincarè characteristic (EPC) was estimated. To deal with the processing of images of the dissectors, a computer program was developed using the GTK+ for MS-Windows. The results were compared to the BMD. RESULTS: It was verified that the measurement of the EPC is correlated with the results obtained by means of the BMD for the lumbar vertebrae. It was also demonstrated that the area of connectivity of the trabecular that is propagated over the dissectors corroborates to ensure that the results of the EPC are consistent with the BMD measurement. CONCLUSIONS: The application of ECP in the analysis of the vertebral tomographies could constitute a method to evaluate the trabecular bone structure, and its correlation with the mechanical resistance of the bone, however being necessary more studies to confirm this data.

Validity of Heart Rate Variability Using Poincare Plot for Assessing Vagal Tone during General Anesthesia / 대한마취과학회지

BACKGROUND: A poincare plot of the heart rate variability (HRV) allows for the quantitative display of the vagal tone in conscious humans. However, relatively little is known about standard deviation 1 (SD1) from the poincare plot reflecting the vagal tone and correlating with the high frequency (HF) spectral power of the HRV during general anesthesia. Thus, the association of SD1 from the poincare plot was examined, along with the HF spectral power of the HRV during general anesthesia. METHODS: Beat-to-beat electrocardiograms were recorded for 5 min in 23 patients (isoflurane group, n = 13; sevoflurane group, n = 10) before, during and after general anesthesia. The low frequency (LF) and HF spectral powers, the LF/HF ratio of the HRV and the SD1 and standard deviation 2 (SD2) from the poincare plot were calculated. RESULTS: Both the HF spectral power of the HRV and SD1 from the poincare plot were reduced following general anesthesia, but recovered thereafter. The recovery of both the HF spectral power and SD1 from the poincare plot in the sevoflurane group was faster than those in the isoflurane group. There were strong correlations between the HF spectral power and SD1 before, during and after anesthesia. CONCLUSIONS: These data suggest that the SD1 from the poincare plot is a useful and valid parameter for analysis of the vagal tone during general anesthesia.

Change of Heart Rate Variability before and after General Anesthesia / 대한마취과학회지

BACKGROUND: This study assessed the changes in the heart rate variability (HRV) indices, which are used to measure the autonomic nervous system function during general anesthesia (GA), and compared the result of the awake state. METHODS: Patients undergoing an explo-laparotomy were anesthetized with either isoflurane (Group I, n = 20) or sevoflurane (Group S, n = 20) added to a mixture of nitrous oxide and oxygen. Frequency-domain analysis of the HRV indices using fast Fourier transformation (FFT) resulted in a power spectrum with a very low (VLF), low (LF), and high frequency (HF) and calculated normalized LF (nuLF), normalized HF (nuHF), and LF/HF ratios before and after GA. Time-domain analysis was performed and the pNN50 (proportion of successive RR intervals [RRI] > 50 ms in relation to the total RRI), RMSSD (root mean square of the successive differences in the RRI), standard deviation 1 (SD1) and standard deviation 2 (SD2) from the Poincare plots, HRV triangular index, and TINN (triangular interpolation of NN interval histogram) were also calculated before and after GA. RESULTS: The VLF, LF, HF, nuLF, and LF/HF ratio during GA decreased by 45.2, 95.1, 83.1, 27.3, and 17.4%, respectively, compared with the awake state. However, the nuHF significantly increased. The RMSSD, pNN50, SD1, SD2, HRV triangular index, and TINN also decreased 62.0, 69.2, 62.0, 61.7, 62.4, and 52.4%, respectively. Groups I and S produced similar alterations in the studied parameters during GA. CONCLUSIONS: GA reduced all the HRV indices studied except for the nuHF.