What does the QRS complex represent in the cardiac cycle?

The QRS complex of an electrocardiogram (ECG) specifically represents ventricular depolarization, which is a critical event in the cardiac cycle. During this phase, electrical impulses travel through the ventricles, leading to their contraction. This contraction is essential for the pumping of blood from the heart to the lungs and the rest of the body.

Understanding the broader context of the heart's electrical activity enhances the significance of the QRS complex. Before ventricular depolarization, atrial depolarization occurs, which is represented by the P wave. After the QRS complex, the heart undergoes repolarization, initially of the ventricles, represented by the T wave. The proper functioning and timing of these electrical events are crucial for coordinating heartbeats and maintaining effective blood circulation.