Abstract:
An electrocardiogram (ECG) measures the electrical activity
of the heart on the surface of the skin. Volume conduction models of the thorax can be designed to
simulate such measurements. However, to drive such simulations a generator function is required to
describe the electrical activity of the heart. Although such simulations, varying in complexity, are
discussed in literature, there is a need for a simplified, though comprehensive approach that can be
used as a concise introduction to this topic, or for cases where one is primarily interested in
first-order approximations of this problem. In this article an overview of the vector interpretation
of the ECG, also known as a vectorcardiogram (VCG), is presented in the two-dimensional frontal
plane of a human. The derivation of the equivalent electric dipole (i.e. the cardiac vector) from
the VCG, which can be used as a current-source generator function for volume conduction model
simulating the ECG, is discussed. A procedure for implementing such a volume conduction model with
the finite element technique, using this simplified two-dimensional generator function, is discussed
and the results are presented. The general features observed in recorded ECG leads agree with those
predicted by this simple model.
AFRIKAANS: 'n Elektrokardiogram (EKG) meet die elektriese aktiwiteit van
die hart op die veloppervlak. Volumegeleidingsmodelle van die toraks kan ontwerp word om hierdie
metings te simuleer. 'n Generatorfunksie, wat die elektriese aktiwiteit van die hart beskryf, word
benodig om hierdie simulasies aan te dryf. Hoewel soortgelyke simulasies van variërende
kompleksiteit in die literatuur bespreek word, is daar 'n behoefte aan 'n vereenvoudigde, dog
omvattende benadering wat kan dien as inleiding tot die onderwerp of vir gevalle waar 'n
eerste-orde-benadering tot die probleem voldoende is. In hierdie artikel word 'n oorsig gegee oor
die vektorinterpretasie van die EKG, ook bekend as 'n vektorkardiogram (VKG), in die
tweedimensionele menslike frontale vlak. Die afleiding van die ekwivalente elektriese dipool (met
ander woorde die kardiale vektor) vanaf die VKG, wat gebruik kan word as 'n
stroombron-generatorfunksie vir volumegeleidingsmodelle wat die EKG simuleer, word bespreek. 'n
Prosedure om so 'n volumegeleidingsmodel met die eindige-element-tegniek te implementeer en die
vereenvoudigde tweedimensionele generatorfunksie te gebruik, sowel as die resultate daarvan, word
bespreek. Die algemene kenmerke van gemete EKG-afleidings stem ooreen met dié wat deur die
eenvoudige model voorspel word.
