Final answer:
The depolarization of the ventricular myocytes produces a QRS complex on the EKG and initiates contraction of the ventricles.
Step-by-step explanation:
The depolarization of the ventricular myocytes produces a QRS complex on the EKG and initiates contraction of the ventricles. The QRS complex represents the depolarization of the ventricles, which is a strong electrical signal that leads to the contraction of the ventricles. This wave of depolarization spreads across the heart and coordinates its rhythmic contractions to propel blood through the circulatory system.