What is the normal range for the PR interval in sinus bradycardia?

• A. 0.08-0.12
• B. 0.12-0.20
• C. 0.20-0.25
• D. 0.25-0.30

Answer: (B)

The correct normal range for the PR interval in sinus bradycardia is 0.12-0.20 seconds. The PR interval reflects the time it takes for electrical impulses to travel from the atria to the ventricles, indicating the function of the conduction system in the heart. A PR interval within this range suggests a normal conduction time and indicates that there are no significant delays.

In sinus bradycardia, the heart rate is slower than normal, but the PR interval can still fall within this standard range, demonstrating that the electrical signals are still being properly conducted through the atrioventricular node. Abnormal PR intervals, either shorter or longer than this range, may indicate potential issues with heart conduction that could require further investigation.

Understanding the significance of the PR interval is vital in interpreting various types of cardiac rhythms, as this helps distinguish between normal and potentially pathological conditions.