A PR interval that is less than 0.12 seconds
•Normal PR interval: 0.12 – 0.20 seconds.
•Short PR interval: < 0.12 seconds.
•Causes of a short PR interval:
•Enhanced atrioventricular nodal conduction (EAVNC).
•Infra-nodal connection between the atria and the bundles (James Fiber).
•Lown-Ganong-Levine syndrome (Short PR interval; narrow QRS complex; clinical tachycardia.
•A delta wave from preexcitation.