Final answer:
The normal PR interval ranges from 0.12 to 0.20 seconds. A PR interval of 0.25 seconds indicates a delay, which could be due to an issue in the heart's conduction system.
Step-by-step explanation:
The PR interval is a part of an electrocardiogram (ECG) tracing that measures the time from the beginning of atrial depolarization (the P wave) to the initiation of ventricular depolarization (the QRS complex). A normal PR interval typically ranges from 0.12 to 0.20 seconds (120-200 milliseconds).
In the scenario where the PR interval is 0.25, there is a delay. The delay would be visible between the P wave and the QRS complex. This delay could indicate a problem with the conduction system of the heart, particularly between the SA node and the AV node.