To evaluate the possibility of resultant cardiac vector of ex vivo guinea pig heart.ECGs were recorded in 4 directions on every plane, and in each direction 4 points at different distances from the anterior, posterior, right and left of isolated guinea pig ventricles immersed in normal saline and distilled water.Main upward waves of ECGs were recorded at all points in 4 directions at 3 levels in the two media. The voltage distribution of normal electrocardial field of the QRS wave was of all-round outward shape, which did not match the resultant cardiac vectors between the left and right and between the anterior and posterior ventricular walls.There are some confusion and contradiction in the resultant cardiac vector based on the voltage distribution of electrocardial field around ex vivo guinea pig heart.