"Funky Trouble Looking" RBBB with AMI

You might remember from my intro that my inspiration for starting the Prehospital 12 Lead ECG blog was the Capnography for Paramedics blog.

You might also recall from my Superlative Hieroglyphicist Award that author of the Capnography for Paramedics blog Peter Canning keeps an active blog called Street Watch: Notes of a Paramedic.

Of course, you probably didn’t need me to tell you that, because he’s been around the blogosphere a lot longer than I have! :)

Regardless, Peter posted a most interesting case study today called “Funky Troubling Looking” — Right Bundle Branch Block and MI that is similar to the case I posted on 11/29/08.

It also dovetails nicely with my recent posts on Sgarbossa’s Criteria.

While Sgarbossa’s Criteria is generally used to identify AMI in the presence of LBBB or paced rhythm, I also discussed the “rule of appropriate T wave discordance” which can be applied to RBBB if it is well understood.

In other words, if you think in terms of the terminal deflection of the QRS complex, and not the main deflection.

*** UPDATE 12/21/08 ***

Here’s an interesting case sent to me by Thomas Bernesser of Mint Hill Fire and Rescue.

50 year old male with an acute onset of sub-sternal chest pain and dyspnea. He states he was at rest when the sharp, tight feeling began in the center of his chest and radiated to his left side. A 10 on 10 with the pain. He also remarked of left arm pain and tingling. He c/o of associated nausea and diaphoresis along with the pain and dyspnea. He had taken two of his own SL NTGs prior to EMS arrival without any relief. He had a past history of multiple MIs with stent placement, the last being in October of this year.

He’s pale, diaphoretic, clutching his chest, looks very uncomfortable and anxious. His initial BP was 92/50, a little tachy between 100-110 and a respiratory rate at about 18/minute.

And on to the EKGs, I ran numerous serial EKGs and they were all identical – including the ones done in the ED at the receiving facility. Just based on his presentation alone I was convinced that he was having a significant cardiac event, but the EKG was a little less convincing for me. Each one of the interpretations made reference to ST elevation in the inferior leads and diagnosed an Acute MI. While I do note elevated segments, the EKG just strikes me as odd. I’m not seeing the classic ST elevation above baseline coming off the S wave of the complex. I might be missing something but I found it interesting nonetheless and wanted to share it with you.

Just so you know, he was worked up in the ER for an MI and sent to the cath lab. He was cathed and came back clean, no signs of occlusion. So, definitely a false MI identification for the Philips MRx.

There’s no perfect solution for patients with baseline abnormalities on the 12 lead ECG. One interesting point for this case is the absence of a definite TP segment as a baseline for ST segment measurement due to the sinus tachycardia.

Normally, we don’t think of RBBB as distorting the ST segment in a discordant direction (which is why LBBB is so problematic). However, both of these cases demonstrate that RBBB can can be challenging when evaluating a chest pain patient.

One final note. Mr. Bernesser advised me that this ECG also fooled the computer at the hospital, which I’m assuming used the GE-Marquette 12SL interpretive algorithm, so it wasn’t just the Philips monitor that gave the >>>> ACUTE MI <<<< message.

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