Which segment of the ECG represents ventricular depolarization?

The QRS complex represents ventricular depolarization on an ECG. This component of the ECG waveform indicates the moment when the ventricles are electrically activated, leading to their contraction. During this phase, the electrical impulse travels through the bundle of His, the Purkinje fibers, and into the ventricular myocardium, resulting in the contraction of the ventricles and the ejection of blood into the aorta and pulmonary artery. The QRS complex typically appears as a sharp, spiked wave on the ECG tracing and is critical for assessing the heart's electrical conduction and the health of the ventricular function.

In contrast, the P wave reflects atrial depolarization, indicating the electrical activity that leads to the contraction of the atria. The ST segment is a period between the end of ventricular depolarization and the beginning of repolarization and provides information about the ventricular recovery phase. The T wave represents ventricular repolarization, which is when the ventricles are recovering and getting ready for the next cycle of depolarization. Understanding these differences is essential for interpreting an ECG accurately and assessing cardiac function.