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Modelowanie wektora magnetycznego serca na podstawie jonowych prądów komórkowych

Micek S., Owsiak D., Surdacki D.

Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna

2008

Vol. 14, nr 3

235-236

Do obliczenia magnetokardiogramów zastosowano dwuwymiarowy model komputerowy elektrycznej aktywności serca, bazujący na formalizmie zaproponowanym przez Hodg-kina i Huxleya. Wyliczano średni wektor pola magnetycznego AMFV (average magnetic field vector) otrzymany z mapy zewnętrznego pola magnetycznego, generowany przez przepływ jonów w poszczególnych komórkach mięśnia serca. Obliczona na podstawie modelu trajektoria AMFV przy normalnej pracy serca w czasie trwania zespołu QRS przyjmuje kształt kolisty z rotacją w kierunku przeciwnym do ruchu wskazówek zegara. Na podstawie modelu przedstawiono przykładowe zaburzenia trajektorii AMFV, towarzyszące określonym zaburzeniom serca.

A two-dimensional computer model of the heart electrical activity, based on the formalism proposed by Hodgkin and Huxley was used to calculate magnetocardiograms. The average magnetic field vector (AMFV) from the map of extra corporeal magnetic field generated by the heart was calculated. In a normal heart, the trajectory of AMFV within duration of QRS complex as computed from the model has a form of a circle rotating anticlockwise. Abnormal trajectories of AMFV associated with some cardiac pathologies were generated from the model, as well. If properly validated in clinical conditions, the measurements of AMFV may be helpful in diagnosis.

The computer model of heart electrical activity

Owsiak D., Micek S.

Biocybernetics and Biomedical Engineering

2005

Vol. 25, no. 2

41-52

The paper describes principles of the two-dimensional computer model of the heart's electrical potential activity based on formalism, created for the cell membrane by Hodgkin and Huxley. The main equations have been shown, and all kinds of heart cells involved in simulation have been considered. The method of obtaining ECG from the model was discussed together with ECG examples obtained from the computer simulations. A comparison of computer simulated and the real ECG for the atrioventricular block has been made. As an example of application, a set of simulation of heart muscIe responses on the external disturbance formed in the impulse have been presented.

Approaches dedicated to the modelling of complex shapes application to medical data

Mari J. L.

Journal of Medical Informatics & Technologies

2004

Vol. 7

IP3--16

The way to model complex shapes has a significant influence depending on the context. Handling an object can be considerably increased if a good underlying model is used. On the contrary, preponderant problems can appear if an unsuited model is associated to the object. The main criterion to discriminate existing models is to determine the balance between: their ability to control global characteristics and the possibility to handle local features of the shape. The fact is very few models are adapted both to structure and to geometrical modelling. In this paper, we first describe an overview of existing approaches. They can be classified principally in two groups: skeleton based models, used to control the global aspect of the shape, and free form models, used to control local specificities of the object. Then, trying to keep the advantages of both techniques in mind, we present an original approach based on a multi-layer model to represent a 3D object. We focus on the ability to take into account both global and local characteristics of a complex shape, on topological and morphological levels, as well as on the geometric level. To do that, the proposed model is composed of three layers. We call the boundary mesh the external layer, including a multi-resolution feature. We enhance this representation by adding an internal structure: the inner skeleton, which is topologically equivalent to the input object. In addition to that, a third layer links the structural entity and the geometrical crust, to induce an intermediary level of representation. This approach is applied to classical and medical data through a specific algorithm.