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Show posters on the hill Optical Mapping of Electrical Activity in Mouse Hearts Niki Florence and Research Assistant Professor Bonnie Punske Nora Eccles Harrison Cardiovascular Research Training Institute Diagram Experimental Setup Photo Diode System I Picture Experimental Setup fiction Potentials ^» Optical Maps of Wild Type Mice Sfiiii speed a[ n hich Lhc electrical Optical Maps Of Genetically Modified Mice With the ever increasing knowledge of the human genome, understanding the physiological effects of genetic alterations is playing an increasing role in science and health care. Genetically altered mice provide us with the opportunity to observe and understand the mechanisms behind changes in structure, function, and electrical properties of the heart. This information will be important in developing better detection methods, diagnosis,and treatment in cardiac related diseases. Optical mapping is a relatively new tool for charting the electrical activity of the heart. Fluorescent dye binds to the cardiac cell membrane when it is perfused through tissue. The dye is volt-age sensitive so when the cell is excited, the membrane voltage rapidly changes, resulting in a corresponding change in the fluorescence of the dye. This change in the fluorescence reflects the change in voltage associated with the action potential of the local heart cells. A charged coupled detector (CCD) camera or an array of photodi-odes can detect these changes in fluorescence and hence collect complete images of the hearts electrical activity including the propagation sequence. In order to process and interpret the optical data and optical maps I have been developing a computer program to estimate the propagation velocities from signals collected from the sur-face of mouse hearts. The algorithm uses a least squares polynomial fit of the activation times which simplifies evaluation of the derivatives for the computation of the local velocities. This code is currently being developed and tested to validate its ability to correctly determine velocity. Upon validation I will use optical signals collected from normal and genetically altered mouse hearts to quantitatively compare and characterize changes in propaga-tion. This data will improve our understanding of the mechanisms and consequences of altered propagation in genetic models of cardiac physiology. {70} |
