"Funky Troubling Looking" — Right Bundle Branch Block and MI

As I mentioned in a recent post, we have a process for instituting a STEMI alert to, in consultation with an ED doctor, activate the cath lab prehospitally based on clinical assessment and a 12-Lead ECG. The coordinator at the hospital that I transport most of my patients to told me so far EMS is batting 1000 when it comes to accurately calling STEMIs, but he did add the reason for that is EMS has been very conservative in calling for the cath lab. In other words, only the obvious STEMIs are getting called in. I can understand that as I am guilty of it myself. If I have an no-brainer, I don’t hesitate to call in, but I don’t want to call in a false alarm. The coordinator said he would like to see people being more aggressive, calling in to consult with the MD even in marginal cases. If the MD isn’t convinced, he can always delay calling until arrival at the hospital. The coordinator did say when EMS activated the cath lab, it is cutting door to balloon time in half.

I had this call the other day:

Chest pain at a local factory that employs a lot of temporary help, and where we are often called for get-out-of-workitsis. We find a muscular 40-year-old male with some serious Biggie Smalls gold bling around his neck. He is lying on the ground rolling around holding his chest. We wheel the stretcher over to him, and I, unimpressed, say, “Get on the stretcher,” which he does, although he continues to grimace quite excessively. There is a bit of coworker crowd there, so I say to my partner, let’s just get him out into the ambulance. I prefer working people in the ambulance. There is privacy. I have everything I need there, and if anything turns bad, we are already on our way to the hospital. Also, actors tend to cease their dramatics once they are in the ambulance, out of sight of their audience.

In the ambulance, I have him take off his shirt, which reveals a thick scar across his abdomen. He tells me got stabbed many years ago. His only current history is HTN, although he admits to a family cardiac history. He is quite muscular but denies any recent muscle strain. He was opening boxes at work when the pain started, but noting so strenuous to cause a muscle tear. The pain is substernal, squeezing and not affected by movement. While I take his vitals, which are quite good, my partner puts him on the monitor. The initial three lead looks a little funky. And then he comes the full 12-lead:

Okay so he has a right bundle branch block. I have to admit I have rarely seen a right bundle branch in a 45-year-old, and there is what I would call an atypical pattern in V2 and V3. It looks like an ST elevation coming off the bundle. Odd. I know a Left bundle branch block can obscure an MI, but I am not so sure about a right bundle. Still, it is enough for me to take a little more seriously than if he was in a perfect sinus.

I give him 02 by cannula, pop in a line, give the ASA and nitros (one every 5 minutes) which provide no relief. When I patch to the hospital — I do not call a STEMI alert, but I say something along the lines of “the patient has a right bundle branch block, but it is sort of funky troubling looking. No idea what his norm is.”

I do a bunch of serial ECGs and they are all the same. I should take some relief in that, but the last one I do, has something else troubling. The computer has decided to call the strip an “ACUTE MI SUSPECTED” even though it looks exactly like the other 12-leads.

At the hospital, I tell the nurse I am troubled and we both approach a doctor and show him the strip. I preface, by saying I know it is a right bundle, but it doesn’t look like a normal one. He is not certain what to make of it, so he walks over to the patient and starts questioning him, and agrees he needs the full cardiac workup. They draw labs, and hook him up to some heparin and nitro.


A week later I get the followup. About an hour after I left the ED, after consulting with cardiology, they take him up to the cath lab, where it is discovered he has a 90% lesion in the left anterior descending artery. For some reason they can’t cath him properly, so he ends up getting cardiac bypass.

Interesting call.

Here’s a final closer look at V1-V3


Some tidbits I learned about RBBB.

It is in fact very rare in men under 50 ( less than .7 percent of the population.)

Gennerally speaking an RBBB does not obscure a STEMI like a LBBB can.



In researching other systems STEMI alerts, I discovered in Massachusetts there are some hospitals that have a dual STEMI alert. The medic can call in and say “I have a definite STEMI” or they can say “I have a possible STEMI.” The definite STEMI gets the cath lab alert, the possible STEMI just gives the cath lab a heads up.

If I had such a choice I would have called in a possible STEMI on this one.

I also have to give props to the LP12. After apparently waffling on making a call, it finally came down on the side of the STEMI.

I know there is some talk of having basics in our states get 12-lead monitors that they will not be able to interpret, but if the patient is having clinical signs of an MI and their strip reads Acute MI Suspected, they may be able at some point to activate the cath lab if no paramedic is available on the call.


  • Tom B says:

    Awesome case! Don’t feel bad. This would have been difficult for anyone.I posted a similar case a few weeks ago, and they didn’t activate the cath lab until there was obvious ST segment elevation in the right precordial leads (which did not happen until arrival at the hospital).See:82 yom CC: chest painIn addition to the “funky” looking ST segments in the right precordial leads, the tip-off for your case is the reciprocal changes visible in inferior leads II, III and aVF, which present as concordant ST segment depression.You can learn about “the rule of appropriate T wave discordance” in a two-part series I did on Sgarbossa’s Criteria this week.See:Identifying AMI in the presence of LBBB – Sgarbossa’s Criteria – Part IIdentifying AMI in the presence of LBBB – Sgarbossa’s Criteria – Part IIThanks for sharing.

  • TOTWTYTR says:

    The “Possible STEMI” criteria is for cases just like this. Ones where you have nothing definitive, but the little alarm bell is still ringing itself silly inside your head. I had one last winter that was such a case. 74 y/o male, with only a history of prostate CA (in remission) that had chest pain without dyspnea while shoveling snow. The ECG, several of them in fact, was not at all clear cut. NTG did nothing. We transported and I called in the case as a “possible STEMI”. When we arrived I showed the attending the ECG. He agreed with me that there was nothing clear cut and then said, “But I’m calling the cath lab anyway”. 15 minutes later they found a 100% occlusion of the LAD and ballooned the patient. Sometimes you (and the attending) just have to trust your gut. Good work.

  • Tom B says:

    P.S. Word verification “xyper”

  • Cayce says:

    We use the Sgarbossa criteria in my county. It really helps with identifying a STEMI in BBB and LVH. We will call a STEMI alert based on +Sgarbossa without the presence of ST elevation, although I’m curious as to the stats of how many patients were taken to the cath lab afterwards. I think it would be nice to formalize a “Possible STEMI alert” to make the transport decision more cut and dry. We have a LARGE hospital network that really hates repatriation when we take their patients to other hospitals. BTW, if you ever get a chance to take a Tim Phalan 12 lead class do it. He teaches the Sgarbossa criteria as part of the imposter rule out. My company had him do some classes for the medics in county and it was really beneficial. It resulted in more interpretation by medics and less of the LP-12 telling us which hospital to go to.

  • Anonymous says:

    I would have done the same thing you did, let them know I’m concerned, but not activate the cath lab. BTW, since the subject of letting the ECG diagnose came up, an old joke around here goes “do you know what they call the person who diagnoses based on what the ECG says (i.e. ACUTE MI SUSPECTED)?The defendant.

  • Walt Trachim says:

    Wow – funky looking 12-leads, indeed. Great call, though. Definitely enough going on to make anyone err on the side of caution, I think.I agree with Cayce about Tim Phelan and the Sgarbossa criteria. We got this training when I was in medic school, in fact. Made for a nice foundation in 12-lead interpretation.

  • Tom B says:

    Sgarbossa's criteria wasn't designed for LVH, but you are correct in that concordant ST segment depression in the right precordial leads would be a grossly abnormal finding with LVH, and probably suggestive of AMI.You have to be careful with the > 5 mm discordant ST segment elevation criterion, especially with LVH, since we know the deeper the S wave, the higher the ST segment elevation. So that criterion isn't very specific when deep QRS complexes are present. You may be better off thinking in terms of % of QRS complex.The GE-Marquette 12SL interpretive algorithm gets a bad rap. It's not very good at rhythm analysis, but when it's a chest pain patient, and the data quality is good (no artifact), it has a very high specificity when it gives the *** ACUTE MI SUSPECTED *** message, particularly when the patient is not tachycardic.It's a tool, like any other. In other words, it needs to be well understood. I'm not aware of anyone who has suggested the patient be "diagnosed" based on the interpretive statement. Remember that ED physicians don't diagnose chest pain, they risk stratify chest pain. Risk stratification includes ST segment elevation or depression on the 12 lead ECG.The key issue is triage of suspected STEMI patients. I know many of you feel strongly that relying on computerized interpretive statements is a step backward for EMS. Certainly there are areas where the paramedics can make the call with a high degree of accuracy (Boston, Ottawa, Seattle) but even there, there will be fall-outs. That's life.The goal is to develop a program that works, and I personally don't believe there is a "one size fits all" solution for every EMS system, based on the heterogeneity of EMS systems and the accompanying financial and political realities. I personally think a combination of methods is optimal.The deeper issue is EMS education and training. Does it need to be improved? You bet. But there's not wide agreement on that point. There are also many areas that are BLS only, so obviously those areas would be confined to computerized interpretation or transmitting the ECG, if the 12 lead ECG is to affect transport destination.Take it away, TOTWTYTR! Key word: brumbe

  • Mark says:

    I say good on all of you for fine tuning your 12lead skills but let us not forget to treat the patient first and the EKG second. If it walks and talks like a duck…guess what…it's get'n cath'd. Read your patient…not the ECG!

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