On an ECG, which feature marks ventricular depolarization?

On an ECG, which feature marks ventricular depolarization?

• A. P wave
• B. QRS complex
• C. T wave
• D. PR interval

Answer: (B)

Ventricular depolarization is represented on the ECG by the QRS complex. The ECG shows electrical activity as waves corresponding to heart muscle events. The P wave marks atrial depolarization, while the QRS complex follows after the impulse travels through the AV node and rapidly through the His-Purkinje system to the ventricles, triggering ventricular contraction. The T wave is ventricular repolarization, the reset of the ventricles after contraction. The PR interval reflects the conduction time from the start of atrial depolarization to the start of ventricular depolarization.

Ventricular depolarization is represented on the ECG by the QRS complex. The ECG shows electrical activity as waves corresponding to heart muscle events. The P wave marks atrial depolarization, while the QRS complex follows after the impulse travels through the AV node and rapidly through the His-Purkinje system to the ventricles, triggering ventricular contraction. The T wave is ventricular repolarization, the reset of the ventricles after contraction. The PR interval reflects the conduction time from the start of atrial depolarization to the start of ventricular depolarization.