We have the Q wave, the R wave, and the S wave. Now, the Q wave and the Swave are known as the downward deflection waves because they actually decrease our voltage. They make it more negative. But the R is known as our right side up, or the upward deflection wave because it increases the voltage, it makes it more positive now, what exactly takes place within the QRS? So here we have the electrical signal that permeated through the entire walls of our right and left ventricle. And now what begins to happen as soon as we reach the maximum point of the R way, this voltage here contraction of these ventricles begins to take place.