ATRIOVENTRICULAR NODAL REENTRANT TACHYCARDIA (AVNRT):

A supraventricular tachycardia (SVT) due to a reentrant circuit within the atrioventricular (AV) node

ECG findings:

-Most common SVT.

-Narrow QRS complexes.

-May have retrograde P waves.

-If P waves are present, the R to P interval is usually < 50% of the R to R interval.