ATRIOVENTRICULAR REENTRANT TACHYCARDIA (AVRT):
A supraventricular tachycardia (SVT) due to reentrant circuit with one pathway within the AV node, and one pathway outside of the AV node (bypass tract).
ECG Findings:
Orthodromic:
– Reentrant circuit goes down the AV node and up the bypass tract.
– 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.
Antidromic:
– Reentrant circuit goes down the bypass tract and up the AV node.
– Wide QRS complexes.
– May resemble ventricular tachycardia.