SIMULTANEOUS DETECTION OF WAVE PROPAGATIONVELOCITY AND DIRECTION IN OPTICAL MAPPING DATAOF CARDIAC EXCITATION USING OPTICAL FLOW

摘要

It is important for analysis of wave propagation to obtain both velocities and directions of a wavefront at a given point when we investigate reentrant activities obtained by optical mapping technique using voltage sensitive dye. Although action potentials and Isochronal Map have been used for analyzing dynamics of reentry, neither of them can show instantaneous velocities and directions of wave propagation at a local region. Optical flow is a mathematical method to obtain distribution of apparent velocities of movement of brightness patterns in an image. It can determine the moving object's instantaneous velocity and direction simultaneously. It has been used in robotic vision and biomedical image analysis. Assuming that wavefront region of cardiac excitation moves as a continuous object, optical flow was applied to obtain wave propagation velocity and direction at a given point in optical mapping data of a perfused rabbit heart. Velocities and directions of a wavefront and during reentrant activities could be calculated in consistent with shape of reentry. The obtained velocities and directions of a wavefront computed by optical flow agreed well with that obtained from isochronal map derived from the same data.