FL_Medic Posted May 4, 2009 Share Posted May 4, 2009 Another strip for you to deduce. Unsure of PMHx, I found this laying in the ambulance. Link to comment Share on other sites More sharing options...
akroeze Posted May 4, 2009 Share Posted May 4, 2009 (edited) Correct me if I'm wrong as this is something I just taught myself yesterday but.... I'm seeing a left axis shift and estimating it to be about -45 degrees. Am I way off? I would call this 3rd degree AVB with a ventricular tachycardia escape and the p waves look to be running at a sinus tach Get a line and be ready to treat but as long as these are perfusing beats no specific treatment to be done in the field. Just be ready for the worst. Edited May 4, 2009 by akroeze Link to comment Share on other sites More sharing options...
scott33 Posted May 4, 2009 Share Posted May 4, 2009 (edited) Yes there is Left axis deviation, and also a LBBB. But I need a closer look at the PRI to see if there is also an AV block. So, yeah...possible tri-fascicular block here (edit: Possible old inferior wall MI too by the looks of it) Edited May 4, 2009 by scott33 Link to comment Share on other sites More sharing options...
akroeze Posted May 4, 2009 Share Posted May 4, 2009 I want to change to say that I would say the axis is more like -60 degrees after I looked over it again Link to comment Share on other sites More sharing options...
scott33 Posted May 4, 2009 Share Posted May 4, 2009 I want to change to say that I would say the axis is more like -60 degrees after I looked over it again I just use my thumbs on I and AVF (or I, II, and III if you want to determine pathological left, from physiological left) Link to comment Share on other sites More sharing options...
FL_Medic Posted May 4, 2009 Author Share Posted May 4, 2009 (edited) I want to change to say that I would say the axis is more like -60 degrees after I looked over it again I was just getting ready to tell you about -60. Remember your perpendicular leads. aVR is your equiphasic lead, and lead 3 has the biggest deflection(in limb leads). I bet you figured that out by now though. 3rd degree AVB has no AV association(regular PR interval). Ok, so those that are calling it LBBB, run me through your thought process. Let's say we are unsure if the QRS is 120ms. Edited May 4, 2009 by FL_Medic Link to comment Share on other sites More sharing options...
scott33 Posted May 5, 2009 Share Posted May 5, 2009 Ok, so those that are calling it LBBB, run me through your thought process. Let's say we are unsure if the QRS is 120ms. I use the "turn signal" method. Assuming QRS >120 ms...Find the J-point in lead V1 (terminal point of the QRS complex), and working backwards, find the first deflection at the end of the QRS. Negative = LBBB, positive = RBBB. LBBBs will also usually have an upright Lead I, and V6 with a "slurred" R-wave. Surely if the QRS was < than 120ms, it wouldn't be a true BBB, so one would have to be positive to call it one? Link to comment Share on other sites More sharing options...
FL_Medic Posted May 5, 2009 Author Share Posted May 5, 2009 (edited) I use the "turn signal" method. Assuming QRS >120 ms...Find the J-point in lead V1 (terminal point of the QRS complex), and working backwards, find the first deflection at the end of the QRS. Negative = LBBB, positive = RBBB. LBBBs will also usually have an upright Lead I, and V6 with a "slurred" R-wave. Surely if the QRS was < than 120ms, it wouldn't be a true BBB, so one would have to be positive to call it one? Well, that's a very common method. You have to be sure of the QRSd to use that method though, and this is borderline. Look at the late R-wave progression. R-wave progression is the transition in the chest leads. You usually start with an rS or QS wave in v1 & v2, and in v4 or v5 you will usually have an almost equiphasic QRS(negative and positive deflection almost even). That would be your transitional lead. The R wave becomes more prominant in v5 & v6 in a normal ECG. This 12-lead doesn't have transition until v5. Also, note the discordant T-waves. This is a normal finding in BBB, and is why LBBB are difficult to diagnose STEMI. Discordant means opposite(the t-waves are opposite the QRS) Also, pathological left-axis deviation was mentioned. This is indicative of a Anterior fasicular block. The left bundle branch has two fasicles anterior & posterior. A LBBB is a block of both these fasicles. So, knowing for sure that one is blocked, and having the left vectors we do, I'd say this is probably a LBBB. For more on axis deviation and hemiblocks check out EMS12lead.blogspot.com There is something else about this strip. It was almost caught, but diagnosed incorrectly. Edited May 5, 2009 by FL_Medic Link to comment Share on other sites More sharing options...
akroeze Posted May 5, 2009 Share Posted May 5, 2009 Well if not 3rd AVB then I don't know what to call it. If you map it out there are extra P waves. Is this 2nd AVB 2:1 conduction with abberancy? There are definitely Ps buried in the Ts Link to comment Share on other sites More sharing options...
FL_Medic Posted May 5, 2009 Author Share Posted May 5, 2009 (edited) Well if not 3rd AVB then I don't know what to call it. If you map it out there are extra P waves. Is this 2nd AVB 2:1 conduction with abberancy? There are definitely Ps buried in the Ts Ahah... When you're thinking 3rd degree AVB, also known as complete heart block, there are some things to consider. First off, this rate would definitely make me question 3rd degree. You usually will have a pretty bardycardic patient with a complete HB. Next, the QRS. While these might just be > 120ms, you will usually have a more idioventricular looking complex(>150 ms). In complete HB the SA node has no say, meaning that your atria and ventricles are completely electrically unaffiliated. This means you will have p waves, and QRS complexes, but they will not be related. You can test this by checking your PR-interval. If you have a consistent PR-I, it aint 3rd degree. In 3rd degree your P-P interval will usually remain consistent, and your R-R interval will remain consistent. They will not be related though. So, since you have more P-waves than QRS complexes, and we have ruled out 3rd degree, it is a 2nd degree. 2nd AVB with 2:1 conduction ratio, as you stated, is correct. This is atrial tach with 2:1 conduction. Without knowing the PMHx, what do you think is the cause. There is a certain condition that is very common with this rhythm. Edited May 5, 2009 by FL_Medic Link to comment Share on other sites More sharing options...
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