Atrial depolarization is represented by which of the following waves on an electrocardiogram (ECG)?

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

Answer: (D)

Verified step by step guidance

1. Step 1: Understand the concept of an electrocardiogram (ECG). An ECG is a graphical representation of the electrical activity of the heart, which includes depolarization and repolarization of the atria and ventricles.
2. Step 2: Learn the significance of each wave on the ECG. 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 seen and may represent delayed repolarization of the Purkinje fibers.
3. Step 3: Focus on the term 'atrial depolarization' in the question. Depolarization refers to the electrical activation of the heart muscle, and in this case, it specifically refers to the atria.
4. Step 4: Match the term 'atrial depolarization' with the corresponding wave on the ECG. Based on the definitions, the P wave is the correct representation of atrial depolarization.
5. Step 5: Confirm your understanding by reviewing the sequence of events in the cardiac cycle as shown on the ECG: P wave (atrial depolarization), QRS complex (ventricular depolarization), and T wave (ventricular repolarization).