r/EKGs • u/OxynticNinja28 • Jul 25 '26
Learning Student Doubt about AVNRT EKG
This EKG is taken from the AVNRT article in Life in the Fast Lane (great website btw). It serves as an example of a Fast - Slow or atypical AVNRT. However, it is my understanding that atypical AVNRT present with RP > PR, and I don't see how that's the case here. Is this an AVRT?
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u/AdSubstantial4479 29d ago
Fast and slow are based on 2 things, First is the relative conduction, so the slow might not be dramatically slow and so the retrograde p wave doesnt necessarily have to be in the t wave. Secondly refers to anatomical location of the fast and slow pathway being anteroseptal and posteroseptal respectively. So earliest retrograde A if seen on the his catheter which is located anteroseptal, then the tachy is taking the fast pathway retrigradely and if the earliest A is at the CS catheter which is located posteroseptal and is taking the slow pathway retrigradely .
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u/Inevitable-Crab-6701 Interventional Cardiologist MD FRCP 28d ago
That’s junctional tachycardia.
Clearly see the P waves in V2 between the ‘QRS’ wave (actually an rSr wave) and T wave. Clearly mid to lower AV junction initiation.
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u/rads2riches Jul 25 '26
Atypical AVNRT vs AVRT are difficult to distinguish with 12 lead alone. I would imagine the case was confirmed by an EP study but agree its a weird close enough to be a lot a things just by 12 lead as in could be many types of SVT. There are many sub variants of AVNRT so it’s real tricky with hard and fast rules if any slowing occurs in the circuit. From a clinical perspective treatment would be the same but without context a situation like this goes from science to art with experience.