What is the normal duration of a PR interval?

The normal duration of a PR interval is 0.12 to 0.20 seconds. This interval represents the time taken for electrical impulses to travel from the atria to the ventricles, which includes atrial depolarization and the conduction time through the AV node. A PR interval within this range indicates normal conduction through the heart's electrical system.

When the PR interval is shorter than 0.12 seconds, it may indicate accelerated conduction, potentially due to conditions such as a pre-excitation syndrome. Conversely, a PR interval longer than 0.20 seconds suggests a delay in conduction through the AV node, which could be indicative of a first-degree AV block or other conduction abnormalities. Therefore, understanding the normal range is crucial for identifying potential dysrhythmias and making informed clinical decisions.