Modelagem, Condicionamento e Validação Computacional de um Eletrocardiógrafo Digital de um Canal

Abstract

The electrocardiograph, a monitoring device used to record the heart’s electrical activity described by the electrocardiogram, has become increasingly relevant to the early diagnosis of heart diseases. Given that, the objective of this work was to develop a model for a single channel digital electrocardiograph through simulation and analysis in Multisim, Proteus and MATLAB by using an unfiltered electrocardiogram waveform sample of the bipolar lead I from the PhysioNet website’s database, which will be conditioned, amplified and filtered in order to validate the model. In order to create the electrocardiograph’s model, a bibliographic review of the fundamentals of biochemistry and physiology related to the operation of the device is carried out, as well as a study of common elements of topologies found in the literature. Then, based on the theory and topologies presented, it is introduced a model for the electrocardiograph which has the following elements: power supply, input signal, protection circuit, pre-amplification, right leg drive, high-pass filter, amplification, band-stop filter, low-pass filter and A/D conversion. For the steady state simulation, the signals at the output and input of each proposed stage are analyzed and, lastly, the output wave of the electrocardiograph is plotted and compared to the equivalent filtered sample of the electrocardiogram from the database. In order to verify the operation of the protection circuit, a transient test is also carried out by applying a 2 kV voltage for 50 ms at the input of the electrocardiograph and analyzing the behavior of the input and output waves of the device.