Dear Bryan,
The P-R interval is a measurement on the electrocardiogram (ECG) that measures the duration from the start of the P wave (the electrical signal to start the atrial contraction) to the QRS complex (the electrical signal to start the ventricular contraction). Although the P-R interval is rate-dependent (the faster the rate, the shorter the interval), the lower limits of normal for a 12 year-old is 0.10 second (100 msec). So, 0.08 seconds (80 msec) is short. There are many different potential reasons for this, so without seeing your daughter, knowing her history, or seeing her ECG, I would definitely recommend further evaluation to ensure that there are no other problems with her heart.
Thank you very much for your reply. I am an Internist doing general practice out here in the middle of the Pacific. Looking closer at the tracing, the PR is actually 0.112 secs., We do not have any cardiologist, let alone a pediatric one. Your reply is of immense help.
Now I know she is o.k. Have a super day!
Bryan