What is the normal PR interval range for sinus rhythm?

What is the normal PR interval range for sinus rhythm?

• A. .08 to .10 seconds
• B. .20 to .22 seconds
• C. .20 to .24 seconds
• D. .12 to .20 seconds

Answer: (B)

The PR interval measures the time from the start of atrial depolarization to the start of ventricular depolarization, reflecting AV nodal conduction. In a normal sinus rhythm, this interval is typically between 0.12 and 0.20 seconds (120–200 ms). Values shorter than about 0.12 s suggest unusually fast AV conduction or measurement artifact, while values longer than 0.20 s indicate delayed AV conduction, with 0.20–0.22 s or longer often considered prolonged. So the normal range to remember is 0.12–0.20 seconds.

The PR interval measures the time from the start of atrial depolarization to the start of ventricular depolarization, reflecting AV nodal conduction. In a normal sinus rhythm, this interval is typically between 0.12 and 0.20 seconds (120–200 ms). Values shorter than about 0.12 s suggest unusually fast AV conduction or measurement artifact, while values longer than 0.20 s indicate delayed AV conduction, with 0.20–0.22 s or longer often considered prolonged. So the normal range to remember is 0.12–0.20 seconds.