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, I just shot the portable chest x-ray for bed 8, is he supposed to be so… uh… sleepy? He barely moved when I pulled the x-ray plate out from under him” your x-ray tech asks you as she walks to put the portable x-ray machine back.
“Hmmm. That’s not good.” You and your charge nurse, Shannon, hustle over to room 8. The patient is a 23-year-old male who came in for syncope. He has no past medical conditions, takes no medications, and has no allergies. He had a workup ordered in triage for some basic blood work, a chest x-ray, and an ECG. All of the bloodwork is back and within normal limits.
The patient looks like he’s asleep and his girlfriend is in the room. You can tell that she isn’t thrilled with him. When Shannon touches his arm, he wakes right up and jumps!
“Hey Mr. Jones, how are you feeling? It looks like you may have fallen asleep. Can you tell me a little bit about what brought you in tonight?” you ask him.
“Right now, pretty good, doc!” He tells you. “You know, it’s the weirdest thing. I keep having big gaps in my memory. Like right now, I swear I was getting an x-ray taken and then all of a sudden, it’s the two of you in my room. My girlfriend is super upset with me because we’ll be talking about something and then I just fall asleep on the couch, sometimes mid-sentence! I don’t know what’s going on and I can’t seem to control it!”
“Don’t try and pull that crap again,” you hear his girlfriend tell you. “You just don’t want to have hard conversations about our future and keep pretending to fall asleep. We’ve been together for 4 years, talking about an engagement ring shouldn’t be that big of a deal.”
“Ma’am, tell me about these ‘episodes’ that he keeps having,” you ask the girlfriend, trying to defuse the situation.
“Who cares. He’s faking it. He says he gets anxious about our future cause his mamma don’t like me but I need to know if I’m wasting my time being with him or not. So, we talk about getting engaged, maybe having a kid or two and then he gets this blank look in his eyes and falls asleep. But I’m not falling for it. He wakes up real quick after too and then says something like sorry babe, what were we talking about? Like he doesn’t even know.”
“Well Ma’am,” you tell her, “I’m sorry to hear that you guys seem to be having some relationship problems.” As you turn to ask his girlfriend a follow up question, Shannon hooks the patient up to the ECG machine and starts running an ECG.
“THAT’S THE LOOK!” you hear his girlfriend yell! You turn around and see Mr. Jones passed out again. Almost as quickly as he’s out, he quickly startles awake.
“Sorry, everyone! I must have nodded off again,” he tells you. You and Shannon exchange a glance and take a look at this EKG together:
Well, for this ECG, there’s a normal looking part, a not normal looking part, and then back to a normal part again. Let’s start with the normal parts:
Rate: 68 ish
Rhythm: Normal sinus
Axis: Normal
Intervals: Look pretty normal
Morphology: Also looks pretty normal
Final read: This patient is in very normal sinus rhythm
Ok, now for the fun part:
Rate: 130s
Rhythm: NOT sinus rhythm
Axis: Likely extreme left, but hard to tell since I’m only working with 8 beats…
Intervals: Widened QRS, No PR interval
Morphology: Is this ventricular tachycardia (Vtach)? Something else? Artifact?
Final read: We have a patent in normal sinus rhythm with a run of a weird, wide complex tachycardia in the middle of the strip.
So, what is going on here? We have a patient who’s in normal sinus rhythm but then decides to have a run of an abnormal rhythm. Could this be what’s causing his “sleeping” spells? Or is it just artifact?
Ok, spoiler alert, VTach is my favorite dysrhythmia, so we’re going to do a quick refresher on three of the cooler, subtler findings of VTach that can help us distinguish Vtach from other mimics and see if we can apply any of them to Mr. Jones’s ECG.
Take a look at the following rhythm strip (this is a run of Vtach):
Fusion beats: occur when a ventricular beat and the sinus node fire at the same time and the resulting complexes “Fuse” together giving you a beat that looks like a mix of a ventricular beat and a sinus beat. It’s one of those weird things in medicine that are actually appropriately named.
Capture beats: occur when the SA node “captures” the heart’s conduction system and it looks like a traditional sinus beat in the middle of a run of VTach
If you see either of these in the middle of a run of a wide complex, regular tachycardia, it’s definitely VTach, every time.
Now take a look at this rhythm strip:
Well, there’s a positive blue arrow sign, so that must mean something. This strip shows A-V dissociation (the p waves are pointed out with blue arrows and don’t relate to the QRS complexes at all). If you see A-V dissociation, it’s another tip off for VTach.
So, what is going on with Mr. Jones? Is he having true cardiogenic syncope? Or is he faking it to avoid a tough engagement discussion? Let’s zoom in on the wide complex tachycardia and mark it up a bit:
That’s right! The blue arrows mark out the P waves that show A-V dissociation. The p-p interval is pretty well preserved (the blue lines are all the same length). Mr. Jones is having runs of Ventricular Tachycardia that are causing syncopal events! He doesn’t need a break up; he needs a cardiologist!
You discuss the case with the electrophysiologist on call who agrees to come evaluate the patient and admit him for further work up and a possible ablation. Mr. Jones is thrilled that you found the cause of his symptoms and saved his relationship.
Case wrap up:
- Every patient coming into the ER or clinic with syncope needs an ECG
- When you’re trying to tease out VTach from other mimics, look for:
- Fusion Beats
- Capture Beats
- AV Dissociation
- Another happy relationship saved by the ED
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**
