ECG Pointers: Well, it seems as though your colon is trying to kill your coronaries

Author: Lloyd Tannenbaum, MD (EM Attending Physician, APD, Geisinger Wyoming Valley, PA) // Reviewer: Brit Long, MD (@long_brit)

Hello and welcome back to ECG Pointers, a series designed to make you more confident in your ECG interpretations.  This week, we feature a post from Dr. Tannenbaum’s ECG Teaching Cases, a free ECG resource. Please check it out. Without further ado, let’s look at some ECGs!

“Hey Doc, the EMS ECG computer is beeping, can you take a look at this?” Your charge nurse, Shannon, asks you.

“Sure! Did we get a call from them with report yet?” you ask her.

“No, not yet. Here’s a print out of the ECG:”

Well. I sure hope they call soon. This looks terrible.

Rate: a little tachy, around 110

Rhythm: sinus tachycardia

Axis: normal

Intervals: normal PR interval, narrow QRS complexes, QTc looks good too

Morphology: This does not look good. There is ST segment elevation in leads II, III and aVF with a bit of elevation in V5 and V6 too. This is worrisome!

Final read: This ECG is concerning for an inferolateral STEMI!

“Shannon, this looks like a STEMI, activate the cath lab, please!”

“Sounds good doc, oh hey, that’s the EMS phone ringing, do you mind grabbing it while I activate the lab?”

“Hi! This is Dr. Tannenbaum, go ahead EMS”

“Hey Doc, this is Medic 929 coming your way priority 1 with a pretty concerning patient. Mr. Jackson is a 62 year old male coming in with the ECG we sent you pretty concerning for a STEMI, but here’s the problem” … static …. “Bleeding!” Static… a lot! … Static.”

And the line goes dead.

“Medic 929 come in, this is the hospital, can you hear us?? Medic 929?”

…Nothing.

“Hey Shannon, I don’t know what happened with Medic 929, but we lost them. They’re the ones who sent us that ECG but they said something about the patient bleeding? Maybe? It was too tough to hear. Not sure what’s coming in, let’s start in the resus bay and go from there. Can you ask cardiology to meet us in resus 1? Oh and send Scott in there too, it’s just not a good resus unless I’m getting snarked at by a pharmacist. I have a feeling this patient isn’t going to be as straightforward as I hoped.”

“Sounds good doc, I see lights, so I bet they’re pulling in now.”
You look out the window and see medic 929 coming in FAST. This is not a good sign. The ambulance doors fly open and you see a pale, diaphoretic man who is in and out of consciousness, having his respirations assisted with a bag valve mask. You look at the medic concerned, and she gives you the full story.

“Doc, sorry about the dropped call, not sure what happened. This is Billy Jackson. He’s a 62 year old male who called us for a massive GI bleed. He takes apixaban and aspirin for atrial fibrillation. Today, he had 3-4 massive bouts of melanotic stool and called us. When we got to him, he looked like this. He wasn’t complaining of chest pain, just extreme weakness and massive GI bleeding. He was so weak that we had to carry him out of the bathroom and then sprinted over here. He’s tachycardic to the low 110s and his blood pressure is soft at 70s/30s. We gave him 1 liter of IVF and sent the ECG, but didn’t know if we should activate a STEMI alert or if the ECG changes could be due to the GI bleed? Can you get changes like this from a massive GI bleed? Any ideas?”

“Wow. That’s a good question.” You see the residents start to take over Billy’s resuscitation. You see them calling for crash blood, prepping to intubate, and getting central access. You see Scott hustle over to give some recs on reversing the apixaban and reminding the residents to give some calcium with all of that blood. They seem to have it under control, so this gives you time to look at his ECG, talk to cardiology, and figure out your next steps.

Let’s start with the basics. ECGs can show us times that the heart is under strain. Take a look at this ECG below:

Rate: 160s

Rhythm: No P waves, too fast to be normal sinus

Axis: Normal

Intervals: Narrow QRS complexes, no PR interval, QTc looks ok

Morphology: There is ST segment elevation in aVR and diffuse depressions in most of the other leads. Best leads to see the depressions in this ECG are I, II, V4, V5, V6.

Final read: This is SVT (supraventricular tachycardia) with strain. The strain pattern is seen by ST segment elevations in aVR with diffuse depressions. This heart is working too hard, likely due to the high heart rate!

So, this ECG shows a classic strain pattern, what about our patient? Can you have so much strain that you get a STEMI? Is it a true STEMI that needs a cath lab? You look up from your thoughts and see the interventional cardiologist peeking in on the resus.

“Hey Dr. Cardiology, remember that STEMI that we activated? Well here’s the whole story. He’s actually a massive, unstable GI bleed, but he has these ECG changes. What do you think?”

“Hey Lloyd, I’ll be honest, I can’t take him to the cath lab like this. I have to give a ton of blood thinners in the lab and it will probably kill him. Most likely, the changes that you’re seeing are from his GI bleed causing a low flow state. When you bleed out a large amount of blood so quickly, if the patient has some non-critical stenosis, the volume loss can turn them into critical level stenosis and cause this injury pattern. Here’s what I’d recommend. Please resuscitate this human. He’s in no shape for a cath right now, even if we wanted to. Get a repeat ECG or two and trend his troponin. I’d expect a slight bump to it, but, most likely, it will not be critically high. If he stabilizes and his ECG stays concerning, we can cath him, but I don’t think that his primary problem is cardiac, I think it’s the GI Bleed.”

“Got it got it, not the heart…” and right as you watch your cardiology colleague start to go mildly apoplectic, you add, “But I totally see your point in this case! Cathing him wouldn’t be the right call; we have to fix the low flow state first!”

You see the cardiologist roll his eyes and turn to go assess the patient. You hear him mutter something to himself that you assume must be about how funny ER docs are as you walk back to the main ER.

Case wrap up:

You check back in with the residents and see that they have given Billy several units of blood, have him intubated, and he’s comfortably sedated. His blood pressure has stabilized. This is your window to get that repeat ECG:

Rate: 66

Rhythm: Normal sinus rhythm with sinus arrhythmia

Axis: Normal

Intervals: normal PR, narrow QRS, QTC looks ok

Morphology: The significant ST segment elevation seen on prior ECG is resolving. There is still some slight ST elevation in the inferior leads but not nearly as severe as initially.

Final read: Sinus arrhythmia with some non-specific ST-T wave changes and resolving of the ST segment elevation previously seen. It’s not perfect yet, but the ST changes are not nearly as severe as they were.

The ICU team comes down and rapidly admits the patient. The GI team is standing by in the ICU ready to do an emergent scope. The patient’s initial high sensitivity troponin was 7 ng/L and was trended by the ICU team upstairs. His troponins went 7 -> 50 -> 77 -> 25.

Recap:

1. This was a tough case. There was a lot of uncertainty it took a team approach to appropriately treat this patient.
2. Strain is most often seen on an ECG as ST segment elevation in aVR and diffuse ST segment depression throughout the rest of the leads.
   1. But not always!
3. When patients lose a lot of volume, it can transform some non-critical stenosis into critical stenosis and we can see signs of ischemia on the ECG.
   1. These patients need resuscitation before a clinical disposition can be made!
4. Repeat ECGs and serial troponins can help guide your (and the upstairs team’s) treatment decisions.
   1. Involve your colleagues early with critical patients!

Hit me up with any questions,

Lloyd

**Looking for a dynamic guest lecture on Emergency Cardiology for your Grand Rounds? Reach out here for a lecture request by Dr. Tannenbaum**

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