The action potential is a sudden positive shift in the cardiomyocyte's cellular membrane potential, termed depolarization. Depolarization not only initiates contraction within the affected cardiomyocyte (Described in Cardiac Excitation-Contraction Coupling), but also initiates depolarization of adjacent cardiomyocytes.
Polar Coordinates The coordinate system which depicts the points from the pole to the certain distance at a particular angle is known as âpolar coordinatesâ. The positive horizontal axis in which that particular angle rotates is named as âpolar axisâ.
The three coordinates (Ã¯,Ã¯â , z) of a point P are defined as: 1  The radial distance Ã¯ is the Euclidean distance from the z axis to the point P. 2  The azimuth Ã¯â  is the angle between the reference direction on the chosen plane and the line from the origin to the projection of P on the plane.