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Abstract Introduction Premature Ventricular Contraction (PVC) is among the most common types of ventricular cardiac arrhythmia. However, it only poses danger if the person suffers from a heart disease, such as heart failure. Hence, this is an important factor to consider in heart disease people. This paper presents an ECG real-time analysis system for PVC detection. Methods This system is based on threshold adaptive methods and Redundant Discrete Wavelet Transform (RDWT), with a real-time approach. This analysis is based on wavelet coefficients energy for PVC detection. It is presented also a study to find the most indicated wavelet mother for ECG analysis application among the following wavelet families: Daubechies, Coiflets and Symlets. The system detection performance was validated on the MIT-BIH Arrhythmia Database. Results The best results were verified with db2 wavelet mother: the Sensitivity Se = 99.18%, Positive Predictive Value P+ = 99.15% and Specificity Sp = 99.94%, on 80.872 annotated beats, and 61.2 s processing speed for a half-hour record. Conclusion The proposed system exhibits reliable PVC detection, with real-time approach, and a simple algorithmic structure that can be implemented in many platforms.
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INTRODUCTION: Patient monitoring will tend to decline in the coming years due to a shortage of physical and human resources in hospitals. Therefore, several studies define alternatives to improve patient monitoring using wireless networks. In these studies, a wireless network is used to transfer data generated by medical sensors without interacting with the traffic in the data network of the hospital. However, this approach should be avoided because there are demands for integration between user applications and patient monitoring. Therefore, this paper defines a patient monitoring system, called Wi-Bio, directed to the establishment of IEEE 802.11 networks that allows traffic generated by user applications. METHODS: The formal validation of Wi-Bio was made through the design of Petri nets, and performance analysis was performed through simulations of the Network Simulator 2 tool. The adoption of this approach is justified by the fact that Petri nets allow verification of logical correctness of the designed systems, while simulations allow behavioral analysis of Wi-Bio in overload scenarios where many patients are monitored. RESULTS: The results confirmed the validity of the designed Petri nets and showed that Wi-Bio is able to accomplish the temporal goals imposed by medical sensors, thereby promoting efficient integration of traffic present in the data network and the patient monitoring network. CONCLUSION: As described, Wi-Bio fulfilled its objectives and motivates future studies aimed at complementing the obtained results.
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O controlador do fluxo de líquido atua em uma pinça, ativada através de um motor de passo, que comprime um tubo de descarga a fim de manter a freqüência do gotejamento constante. Ele se baseia em um transdutor infravermelho que transforma o período de gotejamento em pulsos elétricos, que intercepetam o feixe infravermelho de um transdutor fixado no equipo. Os sinais são comparados aos previamente fixados como referências e a tensão elétrica resultante é aplicada no motor de passo que regula a abertura da pinça. Os teste indicam um desvio de 0,2 por cento, erro de 0,87 por cento e histerése de 0.6 por cento além de excelente precisão devido a circuitos especiais adicionados ao aparelho
Abstract - The liquid flow controller acts on a pincer activated by a step-motor. that constrains a discharge tube in order to maintain the drip frequency constant. lt is based on an infrared transducer, that transforms the dripping period in electric pulses when intercepts the infrared beam of the transducer. Submitted to digital treatment, these signals are compared to those previously set as a reference and the resulting electric tension applied onto the step-motor to regulate the pincer overture. Tests shown a very low drift (0.2%), error (0.87%) and histeresys (0.6%), exhibiting an excellent accuracy dueto special circuits added to the device framework