This page covers how to calculate the PR interval on electrocardiograms (EKGs/ECGs).
PR interval: time between the start of the P wave and the beginning of the QRS complex (start of atrial contraction to the start of ventricular contraction). Check to make sure this distance is larger then 3 small boxes (0.12 s) below the size of one big box (0.2 s). If it is longer then 0.2s, this is characterized as first degree AV block.
Page Updated: 03.05.2018