The normal PR interval is 0.12 to 0.20 seconds, or 120 to 200 milliseconds. Note that the PR interval can be altered by changing sympathetic and parasympathetic tone. Because of this, medications ...

The PR interval is the time from the beginning of the P wave (atrial depolarization) to the beginning of the QRS complex (ventricular depolarization). The normal PR interval measures 0.12-0.20 ...

Compared with individuals in whom PR interval was normal, participants with PR prolongation of more than 200 ms had a twofold higher risk of developing atrial fibrillation, a threefold higher risk ...

The first PR interval after the dropped beat is shorter than the last conducted PR interval ... The standards for QRS voltage have been derived from studies of populations of clinically normal ...