Thread by @ecgrhythms

From the archives/sent by a friend series
What is the dx
Digitized using #PMcardioApp
Difficulty level:⭐️⭐️⭐️

*65 yo
*h/o HTN
*pw with fatigue

What is your ECG interpretation? Poll next

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What is your ECG interpretation?
🐦 ur reply if none of the 4 choices

SB-sinus bradycardia
CHB-complete heart block
SR-sinus rhythm
2AVB-second degree AV block
AHB-advance heart block

@PMcardioBot @PowerfulMedical @RobertHermanMD

In 🤪-looking rhythms, a good rule-of-thumb to r/o chb is to ✔️ RR interval. If RRI is irreg then not CHB. It could mean some sinus P's were conducted. CHB have reg RRI.

1/This is a non-📖AHB

The classic def of high-grade AVB or AHB is when the AV conduction ratio is 3:1 or ⬆️. In some cases, there are only ventricular captures and the dominant rhythm is maintained by a subsidiary pacemaker - Chou's Electro in Clin Prax p462

2/In the case, there is initially a 2:1 AV conduction and after R3 there is 9:1 AV conduction. The rhythm is maintained by 4 (R4-7) junctional complexes (rhythm). The 4 junctional complexes can be seen as QRS complexes different from the conducted complexes (R2-4 &8).

3/Occasionally, QRS morphology gives us clue on the source of the impulse (as in this case). R1 is also a junctional complex.