Long and short RP tachycardias are two groups of supraventricular tachycardias depending on the interval between the R wave and the P wave of the next cycle.
Short RP tachycardia:
Typical (slow-fast tachycardia) AV nodal reentrant tachycardia [AVNRT] is the most common type of short RP supraventricular tachycardia. P waves are not seen in 80% of typical AVNRT because it is within the QRS. In 20% it is visible just after the QRS.
AVRT (accessory pathway mediated atrioventricular reentrant tachycardia) is the other form of short RP tachycardia in which the P wave falls at the end of the QRS.
Long RP tachycardias:
Atypical (fast-slow tachycardia) AVNRT: Impulse travels down the fast pathway and back through the slow pathway.
Atrial tachycardia
PJRT – Permanent junctional reentrant tachycardia