scope2776 Posted April 23, 2007 Author Share Posted April 23, 2007 ST Elevation is NOT indicative of LBB and that's is not how you figure it out. The ST segment changes are possibly caused by it, but that's not how you determine if it is a BBB. Whew... calm down.... Maybe I worded myself wrong... but yes characteristic LBBBs cause diffuse ST/J-point elevation. I meant to say, if there was any confusion about STE, it was because it was caused by the LBBB. Not the other way around lol.... I may be looking for answers as to the cause, but if the pt is asymptomatic, I would most definitely NOT be arbitrarily throwing NTG and ASA his way. It could be indicative of an infarct, in which case go for it. But it may also be normal for that pt. Remember to ask the pt if they know they have it, or if they have an old ECG. I can't stress this enough (sorry for shouting) TREAT YOUR PT NOT YOUR MACHINE!!!!! This is a case where I asked for a treatment based solely on the machine, without a pt evaluation. Based on this ECG alone I would have no problem with X1 0.4mg SL NTG, 324 ASA and O2... assuming as I did that their pressure is above 100 sys. Even if their normal is this nasty ECG, a little ASA never hurt anybody... Link to comment Share on other sites More sharing options...
AZCEP Posted April 23, 2007 Share Posted April 23, 2007 You need to look to a source other than the ACLS book for your information scope. You can determine the presence of an MI with a co-existing LBBB. It's a bit more challenging, but you owe it to your patients to do the work. Notice the LBBB pattern. Notice the ST elevation in the lateral leads. Notice also that the ST segment moves in the direction of the QRS complex. In this ECG, if there was evidence of ST depression, we could justify treating this patient as an acute MI based on the ECG. The LBBB does not interfere with this mechanism. You are also being a bit empiric with a treatment that can, and does cause harm on occasion. If your patient is tachycardic due to hypoxia, you better make sure why this is happening prior to giving them aspirin. Ever managed an asthmatic that you've given aspirin to? Not something you want to do to a sick heart. Link to comment Share on other sites More sharing options...
ERDoc Posted April 23, 2007 Share Posted April 23, 2007 Wouldn't want to give it to someone with a disection or aneurysm either. Nitro to either of these pts might not be bad (assuming we don't get a reflex tachycardia) but ASA is a no-no. You CANNOT base your treatment on any EKG alone without a clinical story. Link to comment Share on other sites More sharing options...
medic001918 Posted April 23, 2007 Share Posted April 23, 2007 There's really no story on this one, I think I got it from class. Just going through the butterfly collection and thought I'd share. I didn't black out the machine interpretation because, as most of you probably know - and if you're new you should find out - those interpretations are not always accurate. Usually I disregard them all together. I have a great strip that illustrates this... just how wacky the interps can be... i'll try and post it. This is indeed sinus tach with a LBBB. The ST elevation is characteristic of a LBBB. There are however a couple of premature beats (beats 3 and and 3rd from the right). I think they are either PVCs or PACs, I think those are P waves... i dunno. Based solely on this 12-lead I was looking for treatments for ischemia... Even if my patient was asymptomatic, i'm still going to give 324mg ASA and maybe some nitro (pressure depending) and you bet you socks O2. This is a very concerning ECG, a ischemic heart beating fast, throwing premature beats. I would also wager on an underlying MI. Thanks for the comments! Based soley on this 12-lead, I wouldn't go treating for ischemia. This could be, and most likely is a normal variant for this patient. Without a cheif complaint to go along with the story, it just doesn't look like an MI to my eyes. Giving some O2, sure. Giving some aspirin, maybe. Giving nitro...no way. This is one of those things that you need to look beyond the monitor and look at the entire picture in determining your treatment. If you're going to treat based soley on a 12-lead, you will at some point cause a significant complication for a patient needlessly. Hopefully this was just an excercise and not something that you would never do to an asymptomatic patient in the field. And I'd wager against you and your MI diagnosis. I'm going with normal variant. Shane NREMT-P Link to comment Share on other sites More sharing options...
scratrat Posted April 23, 2007 Share Posted April 23, 2007 Whew... calm down.... Maybe I worded myself wrong... but yes characteristic LBBBs cause diffuse ST/J-point elevation. I meant to say, if there was any confusion about STE, it was because it was caused by the LBBB. Not the other way around lol.... This is a case where I asked for a treatment based solely on the machine, without a pt evaluation. Based on this ECG alone I would have no problem with X1 0.4mg SL NTG, 324 ASA and O2... assuming as I did that their pressure is above 100 sys. Even if their normal is this nasty ECG, a little ASA never hurt anybody... I was not trying to be nasty and I'm still not. BUT, you cannot ask for treatment based 'solely on the machine'. You just can do it. You cannot come up with a treatment plan without knowing whats going on with pt. Link to comment Share on other sites More sharing options...
scratrat Posted April 23, 2007 Share Posted April 23, 2007 AZCEP Thanks for that post! I just took a 12 lead class again and they never mentioned that. They basically state if it's new onset, treat it like an MI until proven otherwise. Link to comment Share on other sites More sharing options...
AZCEP Posted April 23, 2007 Share Posted April 23, 2007 And they never will mention it. It's one of those nuggets of information that can make a world of difference when you need it, but probably never will. I just happened to pick up an advanced 12 lead interpretation book that discussed it. I mean really, how often can EMS know that a LBBB is new or old? Link to comment Share on other sites More sharing options...
Thunderchild145 Posted April 23, 2007 Share Posted April 23, 2007 EMS will almost never know if it's new or old. Your best chance of knowing in the field if a LBBB is new or old is if the patient knows that they have a LBBB. The odds are astronomically stacked against that, so I tend to treat anyone complaining of substernal chest pain according to our CP protocols, with or without presence of a diagnostic 12-lead. Link to comment Share on other sites More sharing options...
scope2776 Posted April 24, 2007 Author Share Posted April 24, 2007 You CANNOT base your treatment on any EKG alone without a clinical story. Okay, yes you all right, a clinical course of action cannot be made solely on an EKG... it was just in exercise in thought process, and the type of patient I might see with this particular strip. You need to look to a source other than the ACLS book for your information scope. You can determine the presence of an MI with a co-existing LBBB. It's a bit more challenging, but you owe it to your patients to do the work. Does the ACLS book even have info on BBBs? :roll: Our Mosby's Paramedics text certainly does not cover MI in LBBBs and neither does Garcia "12-Lead ECG"; beyond be aware for possible MI. I also have Marriott's "Practical Electrocardiography", which I will try and browse for the particulars. (but it is pretty dense reading lol) Anytime in class we talk about LBBBs it's always, treat for a possible MI and don't read too far into it. I know there are some advanced criteria for determining an MI with a LBBB. And I do know it's a little easier to tell with a RBBB. I know LBBBs will have normal ST elevation and RBBBs cause ST depression, so any variation in this atypical presentation may indicate MI. Also, I know in our protocols (for the county EMS) it just indicates to treat for MI, of course if the patients symptomatic, etc. Are there some steps you use to look for possible MI in LBBB AZCEP? Thanks for the enthusiastic replies! Link to comment Share on other sites More sharing options...
AZCEP Posted April 24, 2007 Share Posted April 24, 2007 The mantra from the sources you commonly see will be "You can't identify an AMI with a LBBB", and you will be left to ponder why this is so. The ACLS doesn't spend any time on the topic at all. The Mosby and Brady paramedic books regurgitate the ACLS information almost verbatim. The steps you seek: First: identify the BBB. This is the easy part. QRS wider than 0.10 sec indicates a conduction delay at best. QRS wider than 0.12 indicates the BBB. Second: identify which BB is blocked. Still not so tough, right? It's either right or left. Third: Look for ST changes in leads that the BBB does not directly influence. Lateral and inferior leads have a different view of the events. They will be useful in identifying the presence of other changes that may be masked by the BBB. Fourth: Look for ST changes in the direction of the QRS complex. If the patient is having an anterior/septal wall MI the BBB will not hide the ST change. Due to the direction the QRS deflects, which direction would you expect the ST segment to go? It does become more difficult to identify ischemia using this criteria, but the injury/infarction patterns hold up pretty well. Link to comment Share on other sites More sharing options...
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