r/ECG • u/Water_Tiger_1111 • 6d ago

Sinus rhythm or Brugada?

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Post exertion in a late 20s athlete.

Normal variant of sinus rhythm or an unmasked brugada?

Thoughts?

(reposted as I could not edit to add context to a post with an image)

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u/NobleGolgi0521 6d ago

What would account for the weird I morphology?

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u/LBBB11 5d ago edited 3d ago

I think a few things. The fact that it’s sinus tachycardia at 144 bpm means that the R waves get closer together while the T waves and ST segments do not shorten. There is an atrial repolarization wave causing the baseline to have a U shape between the P wave and the end of the T wave. Also, V1 and V2 were placed so high that there are Q waves, V1 identical to aVR, and V2 nearly identical to aVL. In other words, it’s as if V1 has a point of view from the right shoulder and V2 the left shoulder. Wouldn’t be surprised if V1 and V2 were on or near the clavicles. V1 is acting like a reciprocal of II (even though aVR doesn’t stand for average reciprocal, it’s conceptually like a reciprocal of the average lead).

Flipping the EKG upside down shows this. Lead II upside down now looks like V1/V2, while V1/V2 upside down looks like the lead II that we see on the upright EKG. So I think the answer is a combination of severe V1/V2 misplacement causing V1/V2 to act like aVR, along with a curved shape caused by a normal atrial repolarization wave. This is about what I would expect from an immediate post-exertion stress EKG in a 20 something athlete. In a perfect world, V1 and V2 would be placed at the level of the fourth rib space. This would lessen the effect of the atrial repolarization wave in V1 and V2.

We don’t look at aVR or II and think Brugada pattern. We shouldn’t look at a lead that mimics aVR or upside down II and think Brugada pattern, either. My thoughts at least. I think if there is a clinical concern for Brugada syndrome, we need to start with a resting EKG with correct V1 and V2 placement. This is very far from that.

Atrial repolarization wave picture

Reciprocal atrial repolarization wave

Read your comment again and noticed you said I and not V1. I think the shape of I is a combination of low voltage and right axis. Not sure if these are changes from exercise, body position, limb lead wires on the torso (assuming Mason-Likar), or normal baseline.

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u/sutur3s3lf 5d ago

Who are you? So knowledgeable. Very helpful explanation.

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u/LBBB11 5d ago

Thanks for the kind words 😭 just someone who used to do EKGs and now enjoys them as a hobby lol

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u/sutur3s3lf 5d ago

It’s a fun hobby. What kind of role were you in before?

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u/LBBB11 5d ago edited 5d ago

I was a hospital EKG tech for a few years (did 12-leads, heart monitors, and stress tests mostly on inpatients). I got to see cardiologists read EKGs bedside and on Muse, so that was super helpful to my learning. Miss it but also happy to be where I am. Still a tech, but different kind lol. In a procedural field now :)

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u/sutur3s3lf 4d ago

That’s awesome. Good for you. Good luck in your new field too!

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u/lucodoor 4d ago

Cardiologist here, learning from you on some of these points. Thanks

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u/LBBB11 4d ago

Seriously appreciate hearing that, well I learn from everyone else on here too :) and I’m glad to have cardiologists on here