Is having short pr interval serious?

Can be a problem. The pr interval refers to a measurement in an ekg of how long it takes the pacemaker in the top part of the heart (the atria) to reach the bottom parts (the ventricles). The normal pacemaker is the sinus node, and it should take a certain amount of time to travel from point a to b. If too fast, a shortcut likely exists called an accessory pathway (wpw).These can cause palpitations and other symptoms.