Bipolar sensing through a three dimensional bidomain model with Luo-Rudy membrane dynamics

Previously, most models that simulate the signals recorded by electrodes during cartiac propagation have used a dipole to approximate the source from membrane current (Im. the sum of currents from membrane capacitance and conductance). To simulate the electrical sources during propagation more precisely, a 3D bidomain model with Luo-Rudy membrane model was developed to reconstruct the signals recorded by sensing electrodes during electrical propagation in the heart. The results show that the Im distribution obtained from bidomain model exhibits the pair of the sharp positive and negative Im current layers located at the advancing wavefront. It produces the biphasic sensed voltage on the vertically oriented bipolar electrode with different morphology, than in the dipole model. The signals on the horizontally placed electrode were larger in amplitude compared with the vertically placed electrode at small spacing. Whether the bidomain model results in a more precise representation of sensed signals needs to be validated by experimental studies.