Which part of the electrocardiogram (ECG) represents depolarization of the ventricles?

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

Answer: (D)

Verified step by step guidance

1. Understand the basic components of an electrocardiogram (ECG). An ECG is a graphical representation of the electrical activity of the heart over time. It consists of several waves and complexes, each representing different phases of cardiac activity.
2. Identify the key components of the ECG: P wave, QRS complex, T wave, and sometimes a U wave. Each component corresponds to specific electrical events in the heart.
3. Learn the significance of each component: The P wave represents atrial depolarization, the QRS complex represents ventricular depolarization, and the T wave represents ventricular repolarization. The U wave is less commonly discussed and its origin is not fully understood.
4. Focus on ventricular depolarization: The QRS complex is the part of the ECG that represents the depolarization of the ventricles. This is the period when the ventricles are electrically activated to contract and pump blood.
5. Review the sequence of electrical events in the heart: The sequence starts with the P wave (atrial depolarization), followed by the QRS complex (ventricular depolarization), and ends with the T wave (ventricular repolarization). Understanding this sequence helps in identifying the role of each component in the ECG.