As a medical professional with expertise in cardiology, I can explain the significance of the QRS complex. The QRS complex represents the electrical activity of the ventricles during depolarization, which is the process that initiates the contraction of the heart muscle. This complex is a crucial part of the ECG reading, as it can indicate various heart conditions. Here's a step-by-step breakdown of the QRS complex: 1. The Q wave is the first downward deflection after the P wave, which represents atrial depolarization. 2. The R wave is the subsequent upward deflection, which signifies the main wave of ventricular depolarization. 3. The S wave is the final downward deflection, which completes the ventricular depolarization process. Any abnormalities in the shape, duration, or amplitude of the QRS complex can provide valuable diagnostic information about the heart's electrical conduction system. read more >>

The QRS complex is a name for the combination of three of the graphical deflections seen on a typical electrocardiogram (EKG or ECG). It is usually the central and most visually obvious part of the tracing. It corresponds to the depolarization of the right and left ventricles of the human heart.read more >>