What term describes the rest phase of the ECG cycle?

• A. Repola­rization
• B. QT Interval
• C. Segment
• D. PAC

Answer: (A)

Rest phase of the ECG cycle is the heart’s recovery after contraction, known as repolarization. Once the ventricles depolarize and contract, they return to their resting electrical state, and this recovery is reflected on the ECG as the T wave. This phase is what allows the heart to fill again and be ready for the next beat. The QT interval spans the entire time from the start of ventricular depolarization to the end of repolarization, so it includes both contraction and recovery rather than just the resting phase. A segment refers to the flat parts between waves (like PR or ST segments) and isn’t the rest phase itself. A premature atrial contraction is an early beat from the atria, not the resting recovery phase.