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.