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