When analyzing an ECG, you measure the time between the beginning of the QRS complex and the end of the T wave. Which physiological events are included in this interval?

• A. Atrial depolarization and repolarization.
• B. Ventricular depolarization and repolarization.
• C. Atrial repolarization only.
• D. Ventricular depolarization only.

Answer: (B)

Verified step by step guidance

1. Understand the components of an ECG: An electrocardiogram (ECG) is a recording of the electrical activity of the heart. It consists of several waves and intervals, including the P wave, QRS complex, and T wave.
2. Identify the QRS complex: The QRS complex represents ventricular depolarization, which is the process where the ventricles contract and pump blood out of the heart.
3. Identify the T wave: The T wave follows the QRS complex and represents ventricular repolarization, which is the process where the ventricles recover and prepare for the next contraction.
4. Analyze the interval: The interval from the beginning of the QRS complex to the end of the T wave includes both ventricular depolarization and repolarization.
5. Clarify atrial activity: Atrial depolarization is represented by the P wave, which occurs before the QRS complex, and atrial repolarization is typically masked by the QRS complex and not distinctly visible on the ECG.