Which event does the T wave reflect?

Which event does the T wave reflect?

• A. The atrium contracting
• B. The ventricle contracting
• C. The ventricle relaxing
• D. The atrium relaxing

Answer: (C)

The T wave on an ECG reflects ventricular repolarization—the ventricles resetting and relaxing after contracting. After the P wave shows atrial depolarization (atrial contraction) and the QRS complex shows ventricular depolarization (ventricular contraction), the ventricles return to their resting electrical state, which is what the T wave captures. So the event is the ventricles relaxing. The other statements describe different timing or chambers: atrial contraction corresponds to the P wave, ventricular contraction to the QRS complex, and atrial relaxation isn’t seen as a separate wave because atrial repolarization occurs during the QRS and is masked.

The T wave on an ECG reflects ventricular repolarization—the ventricles resetting and relaxing after contracting. After the P wave shows atrial depolarization (atrial contraction) and the QRS complex shows ventricular depolarization (ventricular contraction), the ventricles return to their resting electrical state, which is what the T wave captures. So the event is the ventricles relaxing. The other statements describe different timing or chambers: atrial contraction corresponds to the P wave, ventricular contraction to the QRS complex, and atrial relaxation isn’t seen as a separate wave because atrial repolarization occurs during the QRS and is masked.