Which ECG component corresponds to ventricular depolarization?

Which ECG component corresponds to ventricular depolarization?

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

Answer: (B)

Ventricular depolarization is represented by the QRS complex. This phase reflects the rapid spread of the electrical impulse through the ventricles, triggering their contraction. The other components have different roles: the P wave is atrial depolarization, the PR interval is the time from the start of atrial depolarization to the start of ventricular depolarization (including conduction through the AV node), and the T wave shows ventricular repolarization as the ventricles reset for the next beat. The QRS complex is typically the largest, fastest deflection due to the brisk activation of the large ventricular muscle mass.

Ventricular depolarization is represented by the QRS complex. This phase reflects the rapid spread of the electrical impulse through the ventricles, triggering their contraction. The other components have different roles: the P wave is atrial depolarization, the PR interval is the time from the start of atrial depolarization to the start of ventricular depolarization (including conduction through the AV node), and the T wave shows ventricular repolarization as the ventricles reset for the next beat. The QRS complex is typically the largest, fastest deflection due to the brisk activation of the large ventricular muscle mass.