Final answer:
The PR interval can be used to measure heart rate.
Step-by-step explanation:
The P-R interval can be used to measure heart rate.
The PR interval measures the duration from the beginning of atrial depolarization (the P wave) to the initiation of the QRS complex. It is more clinically relevant as it reflects the time it takes for the electrical impulse to travel from the atria to the ventricles, which is an important factor in determining heart rate.
For example, if the PR interval is longer than normal, it could indicate a slower heart rate, while a shorter PR interval could indicate a faster heart rate.