today 4:00 a.m. in five we're going to review this garbo stat criteria so first of all let's talk about what you use this garbo is the criteria for the reason this criteria exists is because it's very difficult sometimes to determine in a fit acute MI is happening in the presence of a left bundle branch block so let's talk about first what a normal left bundle branch looks like a normal left bundle should be appropriately discordant this means that the t-wave should be deflected in the opposite direction as the qrs and here's some examples so here's a v1 you have the QRS going down and then your G point in the T wave should be deflected opposite so appropriately discordant and so it's in the positive direction here you have an example in v6 where you have a positive QRS and a negatively deflected T wave so that's normal that is a normal left bundle branch block with appropriate discordance the reason that's important is because if you see a left bundle with concordant waves that could be very concerning that you're looking at an acute MI so here are the criteria outlined by Scarb also that indicate an acute MI could be present in the setting of either a left bundle or a paced rhythm the first one here is probably the most important because it's the highest indicator of acute MI it's when you have an ST elevation greater than 1 millimeter concordant with a QRS complex now this is pretty hard to all imagine so I'm going to use another diagram to explain each of these three criteria this is put out by EMS 12-lead blog so here's a diagram of each of the criteria so here's this first one again very concerning very high sensitivity for acute MI you have a positive QRS complex and a positive T wave and G point elevation that's concordant and should be very concerning and here the criteria says that this concordant wave here should be greater than one millimeter so that's your first one to look out for let's go over here to our second one this is in V one two or three you're going to have your discordant waves in general your QRS is negative here and positive T wave and here you have a depression that is concordant with the QRS so it's in the same direction so have an ST depression or j-point depression greater than one melamine so that's your second criteria also highly concerning for acute MI and third we have here in the middle we have our discordant waves as we would expect for a left bundle here's our negative QRS and our positive T wave and you have an elevation that is greater than five millimeters so basically that's the square Bosa criteria it helps us distinguish between a left bundle and an acute MI and here's the quick summary again now I wanted to go through two EKGs that have examples of each of these so here's our first EKG we have a left bundle let's start out looking at the five and six here so here's five and six here at the bottom and you can also see this in AVL actually so you have concordant waves so you have a positive QRS positive T wave and a positive J point deflection with greater than one millimeter of elevation so you can see that in v5 greater than one millimeter in v6 and over here in AVL greater than one millimeter and AVL very very concerning for acute MI now you also have discordant St elevation greater than five millimeters in v3 so here's our one two and three we have appropriately discordant waves however here in v3 you can see this elevation here the J point is about five millimeters higher so you have a greater than five millimeter St elevation in discordant waves and then here's the example of that last one this is actually in a paced rhythm so remember I said this could either be paste or in a left bundle and in v2 we have an example of discordant waves so downward QRS upward key wave however there's a J point or an ST depression that is concordant with our QRS complex that is greater than one millimeter very concerning for acute MI and there's a really good example in v2 so thanks a lot for joining us on am and five here's some other great references check out the EKG Orioles by dr. Alma Chu and these two dates have some great explanations of the circle Rossa criteria as well