An intelligent portable sensor system in diagnosing stress

Nowadays the stress is a frequent problem in the society. The level of stress could be important in order to recognise health problems later. Electrocardiogram technics allows to supervise the heart condition and the detection of anomalies about the patient. Sometimes the data collection systems by sensors placed on the patient restrict his mobility. Therefore the elimination of wires is a good solution for this trouble. Then the Bluetooth protocol is chosen as way for transmitting and receive data between stations. There are three ECG sensors placed on the right hand, the left hand and the right leg. It is possible to measure the heart signal with this technique. Besides there is an extra sensor in order to measure the temperature of the patient. Depending of the value of these parameters is possible to recognise stress levels. All sensors are connected to a special box with a microcontroller which treat every signal. This module has a Bluetooth part that transmitts wireless the new digital signal to the receiver. This one will be a dongle connected to the computer by Serial Port. A program in the computer has been implemented in order to receive the Bluetooth Data sent from the box and saving the data in a file for subsequent activities. El objetivo principal de este proyecto es el estudio de parámetros como la temperatura corporal y las señales de electrocardiograma para el diagnóstico del estrés. Existen varios estudios que relacionan estos parámetros y sus niveles con posibles casos de estrés y ansiedad. Para este fin usamos unos sensores colocados en el brazo derecho, brazo izquierdo y pierna izquierda. Esto forma el Eindhoven Triangle, que es conocido por dar una señal de electrocardiograma. A su vez también tendremos un sensor de temperatura colocado en un dedo de la mano para medir los grados a los que está el cuerpo en ese momento y así poder detectar ciertas anomalías. Estos sensores están conectados a un modulo que trata las señales analógicas recogidas, las une, y digitaliza para que el modulo transmisor pueda enviar via Bluetooth los datos hacia un receptor colocado en un área cercana. En el módulo hay una electrónica que ayuda a resolver problemas importantes como ruido o interferencias. Este receptor está conectado a un ordenador en el cual he desarrollado una aplicación que implementa el protocolo HCI y cuya funcionalidad es recoger los datos recibidos. Este programa es capaz de crear y gestionar conexiones Bluetooth entre dispositivos. El programa está preparado para que si las conexiones se cortan, se traten en la medida de lo posible los datos recogidos. Los datos se interpretarán y guardarán en un fichero .bin para posteriores usos, como graficaciones y análisis de parámetros. El programa está enteramente hecho en lenguaje Java y tiene un mecanismo de eventos que se activa cada vez que hay datos en el receptor, los recoge y los procesa con el fin de darles un trato posteriormente. Se eligió el formato .bin para los ficheros debido a su pequeño tamaño, ya que aunque sean más laboriosos de usar es mucho más eficiente que un .txt, que en este caso podría ocupar varios megabytes.

Mejora de la calidad de los electrocardiogramas recogidos por terminales móviles

Inicio del desarrollo de un algoritmo eficiente orientado a dispositivos con baja capacidad de proceso, que ayude a personas sin necesariamente una preparación adecuada a llevar a cabo un proceso de toma de una señal biológica, como puede ser un electrocardiograma. La aplicación deberá, por tanto, asesorar en la toma de la señal al usuario, evaluar la calidad de la grabación obtenida, y en tiempo seudo real, comprobar si la calidad de la señal obtenida es suficientemente buena para su posterior diagnóstico, de tal modo que en caso de que sea necesaria una repetición de la prueba médica, esta pueda realizarse de inmediato. Además, el algoritmo debe extraer las características más relevantes de la señal electrocardiográfica, procesarlas, y obtener una serie de patrones significativos que permitan la orientación a la diagnosis de algunas de las patologías más comunes que se puedan extraer de la información de las señales cardíacas. Para la extracción, evaluación y toma de decisiones de este proceso previo a la generación del diagnóstico, se seguirá la arquitectura clásica de un sistema de detección de patrones, definiendo las clases que sean necesarias según el número de patologías que se deseen identificar. Esta información de diagnosis, obtenida mediante la identificación del sistema de reconocimiento de patrones, podría ser de ayuda u orientación para la posterior revisión de la prueba por parte de un profesional médico cualificado y de manera remota, evitando así el desplazamiento del mismo a zonas donde, por los medios existentes a día de hoy, es muy remota la posibilidad de presencia de personal sanitario. ABTRACT Start of development of an efficient algorithm designed to devices with low processing power, which could help people without adequate preparation to undertake a process of taking a biological signal, such as an electrocardiogram. Therefore, the application must assist the user in taking the signal and evaluating the quality of the recording. All of this must to be in live time. It must to check the quality of the signal obtained, and if is it necessary a repetition of the test, this could be done immediately. Furthermore, the algorithm must extract the most relevant features of the ECG signal, process it, and get meaningful patterns that allow to a diagnosis orientation of some of the more common diseases that can be drawn from the cardiac signal information. For the extraction, evaluation and decision making in this previous process to the generation of diagnosis, we will follow the classic architecture of a pattern recognition system, defining the necessary classes according to the number of pathologies that we wish to identify. This diagnostic information obtained by identifying the pattern recognition system could be for help or guidance for further review of the signal by a qualified medical professional, and it could be done remotely, thus avoiding the movements to areas where nowadays it is extremely unlikely to place any health staff, due to the poor economic condition.

Continuous amperometric monitoring of glucose in a brittle diabetic chimpanzee with a miniature subcutaneous electrode

The performance of an amperometric biosensor, consisting of a subcutaneously implanted miniature (0.29 mm diameter, 5 × 10−4 cm2 mass transporting area), 90 s 10–90% rise/decay time glucose electrode, and an on-the-skin electrocardiogram Ag/AgCl electrode was tested in an unconstrained, naturally diabetic, brittle, type I, insulin-dependent chimpanzee. The chimpanzee was trained to wear on her wrist a small electronic package and to present her heel for capillary blood samples. In five sets of measurements, averaging 5 h each, 82 capillary blood samples were assayed, their concentrations ranging from 35 to 400 mg/dl. The current readings were translated to blood glucose concentration by assaying, at t = 1 h, one blood sample for each implanted sensor. The rms error in the correlation between the sensor-measured glucose concentration and that in capillary blood was 17.2%, 4.9% above the intrinsic 12.3% rms error of the Accu-Chek II reference, through which the illness of the chimpanzee was routinely managed. Linear regression analysis of the data points taken at t>1 h yielded the relationship (Accu-Chek) = 0.98 × (implanted sensor) + 4.2 mg/dl, r2 = 0.94. The capillary blood and the subcutaneous glucose concentrations were statistically indistinguishable when the rate of change was less than 1 mg/(dl⋅min). However, when the rate of decline exceeded 1.8 mg/(dl⋅min) after insulin injection, the subcutaneous glucose concentration was transiently higher.

Nonlinear control of heart rate variability in human infants.

Nonlinear analyses of infant heart rhythms reveal a marked rise in the complexity of the electrocardiogram with maturation. We find that normal mature infants (gestation greater than or equal to 35 weeks) have complex and distinctly nonlinear heart rhythms (consistent with recent reports for healthy adults) but that such nonlinearity is lacking in preterm infants (gestation > or = to 27 weeks) where parasympathetic-sympathetic interaction and function are presumed to be less well developed. Our study further shows that infants with clinical brain death and those treated with atropine exhibit a similar lack of nonlinear feedback control. These three lines of evidence support the hypothesis championed by Goldberger et al. [Goldberger, A.L., Rigney, D.R. & West, B.J. (1990) Sci. Am. 262, 43-49] that autonomic nervous system control underlies the nonlinearity and possible chaos of normal heart rhythms. This report demonstrates the acquisition of nonlinear heart rate dynamics and possible chaos in developing human infants and its loss in brain death and with the administration of atropine. It parallels earlier work documenting changes in the variability of heart rhythms in each of these cases and suggests that nonlinearity may provide additional power in characterizing physiological states.

Comparação entre a técnica femoral com dispositivo de hemostasia e a técnica radial em pacientes submetidos à estratégia invasiva precoce

A via de acesso arterial é um importante sítio de complicações após a realização de procedimentos coronários invasivos. Dentre as estratégias para a redução de complicações vasculares, encontra-se estabelecida a eficácia da técnica radial. Os dispositivos de oclusão vascular propiciam maior conforto ao paciente, reduzindo o tempo de hemostasia e repouso no leito. Entretanto, a inconsistência de dados comprovando sua segurança limita sua adoção rotineira como estratégia para redução de complicações vasculares, requerendo evidências de estudos randomizados com metodologia adequada. O objetivo deste estudo foi comparar a incidência de complicações no sítio de punção arterial entre a técnica radial e a técnica femoral com utilização de Angio-Seal em pacientes com síndrome coronariana aguda sem supradesnível do segmento ST submetidos à estratégia invasiva precoce. Trata-se de um ensaio clínico unicêntrico, de não inferioridade, no qual duzentos e quarenta pacientes foram randomizados para a técnica radial ou técnica femoral com utilização de Angio-Seal. O objetivo primário foi a ocorrência de complicações no sítio de punção arterial até 30 dias após o procedimento, incluindo sangramento grave, hematoma >= 5 cm, hematoma retroperitoneal, síndrome compartimental, pseudoaneurisma, fístula arteriovenosa, infecção, isquemia de membro, oclusão arterial, lesão de nervo adjacente ou necessidade de reparo vascular cirúrgico. Em relação às características demográficas e clínicas, houve diferença apenas quanto ao gênero, com presença maior de pacientes do sexo feminino no grupo radial (33,3% versus 20,0%, p=0,020). Não se observaram diferenças entre os grupos quanto ao diagnóstico de admissão, alterações isquêmicas presentes no eletrocardiograma, elevação de marcadores de necrose miocárdica ou escores de risco, bem como quanto à farmacoterapia antitrombótica adjunta e características da intervenção coronária percutânea. A hemostasia foi obtida na totalidade dos procedimentos do grupo radial com a utilização da pulseira compressora seletiva TR Band e em 95% dos procedimentos realizados pela técnica femoral com o Angio-Seal (p=0,029). Exceto pela maior incidência de oclusão arterial no grupo radial comparado ao femoral, não houve diferenças entre os demais desfechos analisados. Segundo o teste de não inferioridade para complicações na via de acesso arterial aos 30 dias, verificou-se que a utilização do Angio-Seal não produziu resultados inferiores ao acesso radial, considerando-se a margem de 15% (12,5% versus 13,3%, diferença -0,83%, IC 95% -9,31 - 7,65, p para não inferioridade <0,001). Os resultados principais deste estudo demonstram que, em uma população de pacientes com diagnóstico de síndrome coronariana aguda sem supradesnível do segmento ST, submetida à estratificação de risco invasiva, a utilização do dispositivo de oclusão vascular Angio-Seal confere ao procedimento efetivado pelo acesso femoral inferioridade na incidência de complicações no sítio de punção arterial aos 30 dias quando comparado ao acesso radial.

Impact of artifact correction methods on R-R interbeat signals to quantifying heart rate variability (HRV) according to linear and nonlinear methods.

In the analysis of heart rate variability (HRV) are used temporal series that contains the distances between successive heartbeats in order to assess autonomic regulation of the cardiovascular system. These series are obtained from the electrocardiogram (ECG) signal analysis, which can be affected by different types of artifacts leading to incorrect interpretations in the analysis of the HRV signals. Classic approach to deal with these artifacts implies the use of correction methods, some of them based on interpolation, substitution or statistical techniques. However, there are few studies that shows the accuracy and performance of these correction methods on real HRV signals. This study aims to determine the performance of some linear and non-linear correction methods on HRV signals with induced artefacts by quantification of its linear and nonlinear HRV parameters. As part of the methodology, ECG signals of rats measured using the technique of telemetry were used to generate real heart rate variability signals without any error. In these series were simulated missing points (beats) in different quantities in order to emulate a real experimental situation as accurately as possible. In order to compare recovering efficiency, deletion (DEL), linear interpolation (LI), cubic spline interpolation (CI), moving average window (MAW) and nonlinear predictive interpolation (NPI) were used as correction methods for the series with induced artifacts. The accuracy of each correction method was known through the results obtained after the measurement of the mean value of the series (AVNN), standard deviation (SDNN), root mean square error of the differences between successive heartbeats (RMSSD), Lomb\'s periodogram (LSP), Detrended Fluctuation Analysis (DFA), multiscale entropy (MSE) and symbolic dynamics (SD) on each HRV signal with and without artifacts. The results show that, at low levels of missing points the performance of all correction techniques are very similar with very close values for each HRV parameter. However, at higher levels of losses only the NPI method allows to obtain HRV parameters with low error values and low quantity of significant differences in comparison to the values calculated for the same signals without the presence of missing points.

Modulação autonômica cardíaca na distrofia muscular de Duchenne durante tarefa no computador

Introdução: A Distrofia Muscular de Duchenne (DMD) é caracterizada como uma fraqueza muscular progressiva que leva à incapacidade. Devido às dificuldades funcionais enfrentadas pelos indivíduos com DMD, o uso da tecnologia assistiva é essencial para proporcionar ou promover habilidades funcionais. Na DMD, além do comprometimento musculoesquelético, uma disfunção autonômica cardíaca também tem sido relatada. Assim, visamos investigar as respostas autonômicas agudas de indivíduos com DMD durante a realização de uma tarefa no computador. Método: A variabilidade da frequência cardíaca foi avaliada através de métodos lineares e não lineares, utilizando uma cinta torácica com equipamento de monitoramento de eletrocardiograma (ECG). Assim, 45 indivíduos foram incluídos no grupo com DMD e 45 no grupo de desenvolvimento típico (controle), avaliados for 20 minutos em repouso sentado e 5 minutos com a realização de uma tarefa no computador. Resultados: Os indivíduos com DMD apresentaram menor modulação cardíaca parassimpática durante o repouso, que diminuiu ainda mais durante a tarefa no computador. Conclusão: Indivíduos com DMD exibiram respostas autonômicas cardíacas mais intensas durante a tarefa no computador

Rastreamento do olhar na avaliação de presença em atividades mediadas por vídeo.

A percepção de presença (PP), evolução do conceito de telepresença, pode ser definida como ilusão perceptiva de não mediação e/ou a percepção ilusória da realidade. O método mais utilizado para a avaliação da PP faz uso de questionários aplicados aos sujeitos, após sua participação numa experiência. Além de não fornecer informações em tempo real esse método sofre muitas interferências advindas tanto dos sujeitos submetidos ao experimento como dos avaliadores dos questionários. Os métodos que poderiam ser mais efetivos para a avaliação da PP, em tempo real, fazem uso de sinais fisiológicos que variam independentemente da vontade dos sujeitos, como batimento cardíaco, eletrocardiograma, eletroencefalograma, resistividade e umidade da pele. Os sinais fisiológicos, no entanto, só variam de forma significativa em situações de estresse, inviabilizando sua utilização em atividades normais, sem estresse. Outra forma de avaliar a PP é utilizar sistemas de rastreamento do olhar. Estudados e desenvolvidos desde o século 19, os sistemas de rastreamento do olhar fornecem um mapeamento do movimento dos olhos. Além de indicar para onde os sujeitos estão olhando, podem também monitorar a dilatação da pupila e as piscadas. Atualmente existem sistemas de rastreamento do olhar comerciais de baixo custo, que apesar de terem menos precisão e frequência que os equipamentos de alto custo são mais práticos e possuem software de plataforma aberta. No futuro serão tão comuns e simples de usar como são hoje as câmeras em dispositivos móveis e computadores, o que viabilizará a aplicação das técnicas e métodos aqui propostos em larga escala, principalmente para monitorar a atenção e envolvimento de atividades mediadas por vídeo. É apresentada uma ferramenta que faz uso do rastreamento do olhar para avaliar a percepção de presença em atividades mediadas por vídeo (com estímulos sonoros). Dois experimentos foram realizados para validar as hipóteses da pesquisa e a ferramenta. Um terceiro experimento foi executado para verificar a capacidade da ferramenta em avaliar a percepção de presença em atividades não estressantes mediadas por vídeo.

Taquicardia ventricular idiopática : estudo de correlação do ECG com o local de origem

Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2014

Modélisation de l’activité électrique des oreillettes avant et après ablation par cathéter

- Réalisé au centre de recherche de l'hospital du Sacré-Coeur de Montréal. - Programme conjoint entre Université de Montréal et École Polytechnique de Montréal.

Optimising care of acute coronary syndromes in three Australian hospitals

Objective. To improve quality of in-hospital care of patients with acute coronary syndromes using a multifaceted quality improvement program. Design. Prospective, before and after study of the effects of quality improvement interventions between October 2000 and August 2002. Quality of care of patients admitted between 1 October 2000 and 16 April 2001 (baseline) was compared with that of those admitted between 15 February 2002 and 31 August 2002 (post-intervention). Setting. Three teaching hospitals in Brisbane, Australia. Study participants. Consecutive patients (n = 1594) admitted to hospital with acute coronary syndrome [mean age 68 years (SD 14 years); 65% males]. Interventions. Clinical guidelines, reminder tools, and educational interventions; 6-monthly performance feedback; pharmacist-mediated patient education program; and facilitation of multidisciplinary review of work practices. Main outcome measures. Changes in key quality indicators relating to timing of electrocardiogram (ECG) and thrombolysis in emergency departments, serum lipid measurement, prescription of adjunctive drugs, and secondary prevention. Results. Comparing post-intervention with baseline patients, increases occurred in the proportions of eligible patients: (i) undergoing timely ECG (70% versus 61%; P = 0.04); (ii) prescribed angiotensin-converting enzyme inhibitors (70% versus 60%; P = 0.002) and lipid-lowering agents (77% versus 68%; P = 0.005); (iii) receiving cardiac counselling in hospital (57% versus 48%; P = 0.009); and (iv) referred to cardiac rehabilitation (17% versus 8%; P < 0.001). Conclusions. Multifaceted approaches can improve care processes for patients hospitalized with acute coronary syndromes. Care processes under direct clinician control changed more quickly than those reliant on complex system factors. Identifying and overcoming organizational impediments to quality improvement deserves greater attention.

Variability in time delay between two models of pulse oximeters for deriving the photoplethysmographic signals

Pulse oximetry is commonly used as an arterial blood oxygen saturation (SaO(2)) measure. However, its other serial output, the photoplethysmography (PPG) signal, is not as well studied. Raw PPG signals can be used to estimate cardiovascular measures like pulse transit time (PTT) and possibly heart rate (HR). These timing-related measurements are heavily dependent on the minimal variability in phase delay of the PPG signals. Masimo SET (R) Rad-9 (TM) and Novametrix Oxypleth oximeters were investigated for their PPG phase characteristics on nine healthy adults. To facilitate comparison, PPG signals were acquired from fingers on the same hand in a random fashion. Results showed that mean PTT variations acquired from the Masimo oximeter (37.89 ms) were much greater than the Novametrix (5.66 ms). Documented evidence suggests that I ms variation in PTT is equivalent to I mmHg change in blood pressure. Moreover, the PTT trend derived from the Masimo oximeter can be mistaken as obstructive sleep apnoeas based on the known criteria. HR comparison was evaluated against estimates attained from an electrocardiogram (ECG). Novametrix differed from ECG by 0.71 +/- 0.58% (p < 0.05) while Masimo differed by 4.51 +/- 3.66% (p > 0.05). Modem oximeters can be attractive for their improved SaO(2) measurement. However, using raw PPG signals obtained directly from these oximeters for timing-related measurements warrants further investigations.

Electrodynamic heart model construction and ECG simulation

Objectives: In this paper, we present a unified electrodynamic heart model that permits simulations of the body surface potentials generated by the heart in motion. The inclusion of motion in the heart model significantly improves the accuracy of the simulated body surface potentials and therefore also the 12-lead ECG. Methods: The key step is to construct an electromechanical heart model. The cardiac excitation propagation is simulated by an electrical heart model, and the resulting cardiac active forces are used to calculate the ventricular wall motion based on a mechanical model. The source-field point relative position changes during heart systole and diastole. These can be obtained, and then used to calculate body surface ECG based on the electrical heart-torso model. Results: An electromechanical biventricular heart model is constructed and a standard 12-lead ECG is simulated. Compared with a simulated ECG based on the static electrical heart model, the simulated ECG based on the dynamic heart model is more accordant with a clinically recorded ECG, especially for the ST segment and T wave of a V1-V6 lead ECG. For slight-degree myocardial ischemia ECG simulation, the ST segment and T wave changes can be observed from the simulated ECG based on a dynamic heart model, while the ST segment and T wave of simulated ECG based on a static heart model is almost unchanged when compared with a normal ECG. Conclusions: This study confirms the importance of the mechanical factor in the ECG simulation. The dynamic heart model could provide more accurate ECG simulation, especially for myocardial ischemia or infarction simulation, since the main ECG changes occur at the ST segment and T wave, which correspond with cardiac systole and diastole phases.

Is pulse palpation helpful in detecting atrial fibrillation? A systematic review

Background Atrial fibrillation in the elderly is common and potentially life threatening. The classical sign of atrial fibrillation is an irregularly irregular pulse. Objective The objective of this research was to determine the accuracy of pulse palpation to detect atrial fibrillation. Methods We searched Medline, EMBASE, and the reference lists of review articles for studies that compared pulse palpation with the electrocardiogram (ECG) diagnosis of atrial fibrillation. Two reviewers independently assessed the search results to determine the eligibility of studies, extracted data, and assessed the quality of the studies. Results We identified 3 studies (2385 patients) that compared pulse palpation with ECG. The estimated sensitivity of pulse palpation ranged from 91% to 100%, while specificity ranged from 70% to 77%. Pooled sensitivity was 94% (95% confidence interval [CI], 84%-97%) and pooled specificity was 72% (95% CI 69%-75%). The pooled positive likelihood ratio was 3.39, while the pooled negative likelihood ratio was 0.10. Conclusions Pulse palpation has a high sensitivity but relatively low specificity for atrial fibrillation. It is therefore useful for ruling out atrial fibrillation. It may also be a useful screen to apply opportunistically for previously undetected atrial fibrillation. Assuming a prevalence of 3% for undetected atrial fibrillation in patients older than 65 years, and given the test's sensitivity and specificity, opportunistic pulse palpation in this age group would detect an irregular pulse in 30% of screened patients, requiring further testing with ECG. Among screened patients, 0.2% would have atrial fibrillation undetected with pulse palpation.

Screening of obstructive and central apnoea/hypopnoea in children using variability: A preliminary study

Aim: Polysomnography (PSG) is the current standard protocol for sleep disordered breathing (SDB) investigation in children. Presently, there are limited reliable screening tests for both central (CE) and obstructive (OE) respiratory events. This study compared three indices, derived from pulse oximetry and electrocardiogram ( ECG), with the PSG gold standard. These indices were heart rate (HR) variability, arterial blood oxygen de-saturation (SaO(2)) and pulse transit time (PTT). Methods: 15 children (12 male) from routine PSG studies were recruited (aged 3 - 14 years). The characteristics of the three indices were based on known criteria for respiratory events (RPE). Their estimation singly and in combination was evaluated with simultaneous scored PSG recordings. Results: 215 RPE and 215 tidal breathing events were analysed. For OE, the obtained sensitivity was HR (0.703), SaO(2) (0.047), PTT (0.750), considering all three indices (0) and either of the indices (0.828) while specificity was (0.891), (0.938), (0.922), (0.953) and (0.859) respectively. For CE, the sensitivity was HR (0.715), SaO(2) (0.278), PTT (0.662), considering all indices (0.040) and either of the indices (0.868) while specificity was (0.815), (0.954), (0.901), (0.960) and (0.762) accordingly. Conclusions: Preliminary findings herein suggest that the later combination of these non-invasive indices to be a promising screening method of SDB in children.