What does the QRS complex of an EKG reflect?

The QRS complex of an EKG reflects ventricular depolarization, which is the process by which the ventricles of the heart contract and pump blood out to the lungs and the rest of the body. During this phase, electrical impulses travel through the ventricles following conduction through the bundle of His and down the Purkinje fibers, leading to the contraction of the ventricular muscle fibers.

This electrical activity is represented visually on an EKG as a sharp, pointed deflection that occurs after the P wave (which represents atrial depolarization). The significance of the QRS complex lies in its ability to indicate not only the timing of ventricular contraction but also the overall health and function of the ventricles.

Understanding that the QRS complex signifies ventricular depolarization is essential because it helps cardiac sonographers assess various conditions, such as arrhythmias, myocardial infarctions, or other cardiac anomalies that may affect electrical conduction through the heart.