Introduction: Atrial Fibrillation (AF) is a common and dangerous condition that have complex driven mechanisms not completely elucidated. Animal models have been of great importance to improve current knowledge of AF. For the better understanding of this condition, a panoramic optical and electrophysiologic mapping setup was created to investigate the AF mechanisms in isolated rabbit heart. This work proposes a pipeline to the three-dimensional analysis of the obtained signals.
Methods: The setup is composed by three high-frequency cameras, separated in 120° between them; two multielectrode arrays for contact mapping with 16 electrodes each; and a tank which simulate the torso, with 60 electrodes uniformly disposed, for non-invasive mapping. Langendorff system is used to perfuse the heart with Tyrode solution. Dye is administrated to obtaining the optical signals.
3D reconstruction: A three-dimensional geometry was generated by rotating the heart, capturing 50 to 100 images along the 360°, then the images was semiautomatically segmented, and Radon Transformation was applied, followed by thresholding, generating a volume. From that, it was obtained a triangular mesh. The epicardium MEA electrodes were manually located in the bidimensional maps, and both were inversely projected in the mesh vertices. For calibration, a triangular prism with 15 landmarks in each face, with known positions, was placed in the center of the tank, and a matrix was generated for transforming pixel-space in real-space coordinates.
Results: The method was applied in 7 experiments, generating the same number of geometries with the signals projected in maps. The method was able to reconstruct the heart geometry with enough fidelity, allowing the three-dimensional signal analysis. The reconstructed signals were consistent with the original maps.
Conclusions: Animal models has been of great importance to improve current knowledge of AF, including elucidating AF mechanisms, areas harbouring arrhythmogenic tissue, with the possibility of implementation of commercial systems.