Orientation and community size dependences of pulsatile electrical field stimulation on lined-up and rod-shaped single cardiomyocytes

We have examined the orientation dependence of minimum electric field intensity for the stimulation of cardiomyocytes, which were cultivated in agarose chambers, using a lined-up cardiomyocyte network with different numbers of cells and orientations. When the cell network was arranged parallel to the electric field, the required minimum electric field intensity decreased to one-fourth as cell number increased, whereas that of the cell network arranged orthogonal to the electrical field did not decrease and was independent of cell number. The required electrical field intensity of the 100 μrn rod-shaped single cardiomyocyte in a microchamber arranged parallel to the electric field was also 40% lower than that of the cell network arranged orthogonal to the electric field. The results indicate that the gradient of the electric field potential between two ends of the cell network or rod-shaped single cell is important for their excitation.