Anterior MI's

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I'm working on my CCRN right now. I graduated in 12/17, and I know I can't sit for it, but I work on a CVU, and I figure I need to know this stuff anyway. I'm working through the EKG interpretations and have come across a segment of my book that says that a RBBB in an anterior MI is an ominous sign, but for the life of me, I cannot figure out why. I am assuming that it has to do with the weakened LV or the fact that a RBBB means that the RV is depolarizing over the LV, O2 demand, and the like, but could someone break it down for me please?

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Specializes in Critical Care.

The right bundle branch is slightly more anterior than the left, and the right bundle branch is fed by the septal arteries which are fed by the LAD, so a new RBBB is highly suspicious for an anterior MI, and as part of a full work up is typically justification for an immediate heart cath.

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Thanks! I was also reading that the LAD supplies the Bundle of His, and that's why a 2nd degree type 2 and 3 degree are also ominous (not that they'reever good), because it indicates that there is now a defect in the conduction pathway.

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Specializes in CVICU.

The LAD supplies everything that lies within the septum. If you see it in a heart cath, the LAD is easily indentifiable by it's "septal hairs" and the fact that it feeds the apex as well.

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The LAD supplies everything that lies within the septum. If you see it in a heart cath, the LAD is easily indentifiable by it's "septal hairs" and the fact that it feeds the apex as well.

No it doesn't. The inferoseptal and midseptal walls have RCA supply. The LAD starts in at the midseptal and anteroseptal and anterial LV wall segments.

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Specializes in CVICU.

I'm sorry for my misinformation @offlabel. I guess all 7 of the cardiologists that I work with on a daily basis are wrong in teaching me what I wrote.

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I'm sorry for my misinformation @offlabel. I guess all 7 of the cardiologists that I work with on a daily basis are wrong in teaching me what I wrote.

No worries. And I really doubt that any cardiologist told you that the LAD supplies "everything that lies within the septum" especially in RCA dominant circulation which is about 85% of patients.

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