Submitted by Dr A Röschl on Mon, 01/13/2025 - 01:49
This ECG (3 rhythm strips) initially shows a sinus rhythm with 1st degree AVB grade I and wide QRS complexes (presumably RBBB pattern). A PAC (P-wave premature, different form than in sinus rhythm) appears approximately in the middle of the ECG, this is not conducte . Due to the strong prematurity, this is not surprising. But why is the 2nd PAC also blocked? The answer can be found inthe second picture.
Submitted by Dr A Röschl on Fri, 11/15/2024 - 01:29
Especially in the social media, one sees again and again similar EKGS like the one shown here with the question: What type of AV block is present here? 2nd degree AVB block type I (Wenckebach) or type II (Mobitz)? It is neither one nor the other!
Here, a PAC can be seen under the blue arrow, which is not conduced because the AV node is still refractory (the refractory period of the AV node depends on the preceding heart rate). Therefore, it is not an AV block, but a physiologically non conducted PAC.
