This ladder diagram is from the following publication Atrioventricular Block with Narrow and Wide QRS: The Pause That Refreshes. The full article can be accessed here:
https://www.ahajournals.org/doi/full/10.1161/CIRCULATIONAHA.121.055990
The authors present the following differential diagnoses:
1. Sinus Rhythm with PVC's
2. Sinus Rhythm with equal His conduction delay
3. Sinus Rhythm with resolution of LBB refractoriness
Here is another great ladder diagram from Chou's Electrocardiography in Clinical Practice (6 ed), Chapter 19: Atrioventricular Block; Concealed Conduction; Gap Phenomenon.
Incidentally, this hypothesis was constructed before the Kosowsky, et al, publication Multilevel Atrioventricular Block (Circulation, Vol 54, No 6, 1976).
I wonder if we can further extrapolate the original diagram by subdividing the AV junction (or, AV node) into upper and lower level components. It may look something like this:
The basic idea is that there is Wenckebach conduction in the upper level (UL), and fixed ratio conduction in the lower level (LL). This can be tricky to appreciate, so the repeating pattern has been colorized for enhanced optics.
The first cycle of the 4:3 Wenckebach (WB) is green, then repeats itself in yellow. I assume this pattern would continue to manifest had the telemetry been longer.
The (assumed) LL fixed conduction ratio of 3:2 is demarcated in red and purple.
The opposite of this pattern (that is, fixed ratio in the UL and Wenckebach in the LL) is hypothesized here:
https://ecgladder.blogspot.com/2023/09/atrial-flutter-with-variable-block.html
ECG from Arron Pearce, @Arron_Pearce_
He asks:
Interesting rhythm case which I think is an atrial flutter with multilevel wenckebach block. I've never seen a baseline in lead II like it. I think it looks strange because of the way that the flutter waves are merging with the T waves Thoughts?
Dave Richley submitted this hypothesis:
Here's another depiction of multilevel AVN block:
https://ecgladder.blogspot.com/2023/09/atrial-flutter-with-variable-block.html
ECG posted to Twitter from @DanielSukmadja
Atrial Flutter with variable block. What sort of relationship is taking place between Atrium and Ventricles? My hypothesis is based on:
Multilevel Atrioventricular Block. Kosowsky, B. D., et al. Circulation, Vol 54, No 6, 1976.
The AV node (AVN) is physiologically divided into upper-level (UL) and lower-level (LL) components, each of which can influence antegrade conduction from Atrium to Ventricles.
I conceptualize it like this:
Each colorized arrow is an antegrade impulse. The green impulse is blocked at the UL. The orange arrow is blocked at the LL. The black arrow successfully reaches the ventricles. Sometimes this behavior, collectively, manifests in a predictable pattern.
The alternating green and blue is to suggest that the UL has a 2:1 block. So, for every 2 impulses that enter the UL, 1 is blocked and does not proceed.
The alternating yellow and orange is to suggest that the LL has a 3:2 block. For every 3 impulses that enter the LL, only 2 proceed into the ventricles. Moreover, the shaded secondary impulse is to suggest that, at this level, the block is particularly Wenckebach.
This ladder diagram is from the following publication Atrioventricular Block with Narrow and Wide QRS: The Pause That Refreshes . The full a...
