What is the normal range for a PR interval?

The normal range for a PR interval in an electrocardiogram (ECG) is 0.12 to 0.20 seconds. This interval represents the time it takes for electrical impulses to travel from the atria to the ventricles through the heart's conduction system, specifically from the atrioventricular (AV) node to the ventricles. A PR interval within this range indicates that the electrical conduction is occurring at a normal pace, ensuring proper timing for the heart's contraction cycle.

If the PR interval is shorter than 0.12 seconds, it may indicate a condition such as a pre-excitation syndrome, where the electrical signals travel more quickly than normal. Conversely, if the interval exceeds 0.20 seconds, it may suggest a first-degree AV block, where there is a delay in the conduction through the AV node. This makes the range of 0.12 to 0.20 seconds crucial for assessing cardiac function and diagnosing potential conduction issues.