What does the 'R' wave in the QRS complex represent?

The 'R' wave in the QRS complex represents ventricular depolarization, which is a crucial phase in the cardiac cycle. During this phase, the electrical impulses travel through the ventricles, leading to their contraction and the subsequent ejection of blood from the heart to the lungs and the rest of the body. The QRS complex itself is a graphical depiction of this electrical activity, and the R wave specifically marks the peak of ventricular depolarization, indicating how well the ventricles are responding to electrical stimulation.

Understanding the role of the R wave is important in interpreting ECGs, as it provides insight into the heart's rhythm and helps identify various cardiac conditions. The QRS complex overall reflects the transition from the prior phase of atrial contraction to the powerful contraction of the ventricles, thus highlighting the importance of the R wave in the overall functioning of the heart.