What is the normal duration for a PR interval in a sinus rhythm?

The normal duration for a PR interval in a sinus rhythm is indeed 0.12-0.20 seconds. This measurement is crucial in assessing the conduction of electrical impulses from the atria to the ventricles through the AV node. A PR interval within this range indicates that the electrical signals are being transmitted effectively and without delay, which is essential for maintaining a coordinated heartbeat.

When the PR interval is prolonged beyond 0.20 seconds, it suggests a possible conduction delay known as first-degree AV block. Conversely, if the PR interval is shorter than 0.12 seconds, it may indicate an accessory pathway of conduction, as seen in conditions like Wolff-Parkinson-White syndrome. Understanding the normal range helps healthcare providers interpret ECGs accurately and identify potential cardiac abnormalities.