Which waveform represents the T wave?

• A. P wave
• B. QRS complex
• C. T wave
• D. U wave

Answer: (C)

In an ECG, the sequence of waves tracks the heart’s electrical cycle: atrial activation, ventricular activation, and ventricular recovery. The T wave specifically marks ventricular repolarization, the ventricles resetting electrically after contracting. It appears after the sharp QRS complex and is typically a smooth, rounded deflection that is smaller and broader than the QRS spike. This contrasts with the P wave, which is a small bump before the QRS that represents atrial depolarization, and with the U wave, a smaller hump that may follow the T wave and is not as consistently present. So the waveform that corresponds to the T wave is the rounded deflection after the QRS complex, reflecting the ventricles finishing their electrical recovery.