Physiology of ST Segment Elevation and Depression Explained

This video will go over the basic physiology of ST segment elevations and ST segment depressions and why they occur in the setting of myocardial ischemia and infarctions (STEMI/NSTEMI).
*Correction: Criteria for ST Depressions are depressions greater than 0.5mm
Time Stamps:
00:00 Intro
00:35 ST Change Criteria & J-Point
05:09 ST Segment Depression
05:41 Sub-endocardial Ischemia
14:42 Normal vs ST Depression
16:52 ST Segment Elevation
17:36 Transmural Ischemia
19:25 Normal vs ST Elevation
#STEMI #ECG #MedRounds101
If you would like to view a video on ECG basics, you can find that here:
• Beginner's Guide to EC...

[@brandtrh3977]

I never take the time to comment on any videos, but this was exceptionally succinct and easy to follow. So glad for teachers like you, bravo!!

[@medrounds101]

So kind of you :) I'm glad you found the video useful!

[@smithy280663]

very well explained........many thanks.

[@mohammad.s2393]

Wooow! Couldn’t be explained better! Thanks

[@ajanannamalai1443]

Thank you so muchhhh. Honestly made my whole understanding of cardio better!

[@medrounds101]

I'm glad you found it helpful :)

[@yahiamohamed1211]

At last I understood THANK YOU from deep heart

[@cherrrriii]

this is just amazing thank you TT

[@aadityavishisht]

Phenomenal

[@jazzbrar450]

wow !!! love how you explained it .

[@dennisyu8711]

thank you so much! finally makes sense

[@medrounds101]

I'm glad it was helpful!! :)

[@quur1915]

Thank you so much i've rlly searched for this kind of explanation and couldnt find it 🙏🏻❤️ god bless you brother

[@medrounds101]

Really happy you found it useful!!

[@georgen9755]

+

[@sajjadmahmudrozin2828]

No one like u taught like this way

[@Dana-rm8cs]

Very helpful

[@mohammadalisadeghi9068]

Thanks so much .

[@is44ct37]

Absolute banger

[@debigdogk9563]

GOATT.- Greatest Of All Time Teacher. Thank you thank you and thank you. God bless you for teaching ❤❤❤❤

[@medrounds101]

Haha very kind of you. Much appreciated :)

[@ahsanbhutta4896]

That was really helpful

[@AhmedOsamaZayed]

Thank you ❤

[@jayedhossain6336]

Fantastic.

[@vittorpollux5042]

THANK YOU 1000 TIMES

[@TheRandomGuy-fj7un]

underrated

[@StyleshStorm]

Very well explained. Thank you so much. Such a underrated topic. Is ST Depression only upon one lays flat on their back a sign of anything?

[@medrounds101]

Thank you so much! I'm not aware of a condition that would do that... if there is one, I'd love to hear about it!

[@gerardtchinda7680]

This is really excellent. thanks a lot.

[@SourChip123]

What resource did you use to learn EKGs? This video was great and I'd love to know where you learned initially.

[@medrounds101]

I've had some brilliant teachers and also happened to come across this, essentially, basics of cardiology book a while back that went though some concepts of electrophysiology and echocardiograms. It was in Japanese, and I can't quite remember to title at the moment but I'll come back to mention it if I find it. I have been recommended "The only EKG book you'll ever need" by Malcolm Thaler a lot but I personally have not had the opportunity to go through that yet.

[@SourChip123]

​@@medrounds101 I have a copy of that book I found online so ill definitely give that a look too. Thanks a bunch for this video and the response.

[@drgadham]

❤teaching 👌🏼👌🌈

[@agenziacentrale4383]

ST elevation could also be early repolarization.

[@medrounds101]

Very true!

[@melodiousmedico2165]

Wow

[@lindsayallen4022]

This is fantastic. Can you explain reciprocal changes?

[@medrounds101]

Yes! So to understand the concept of reciprocal changes, you'll have to be familiar with the direction (vector) that each of the leads are pointing to. In the video example at 19:35, the ECG wave drawn roughly represents what we would expect to see in lead II. If we were to take the same MI scenario but looked at how lead aVR (which roughly points in the opposite direction as Lead II) would have looked like, the ST segment would actually look like a depression since the constant "noise" that shifted the ECG wave downwards in lead II would have shifted the ECG wave upwards in lead aVR. The ST depression seen in aVR would be considered a reciprocal change to the ST elevation seen in lead II. Essentially reciprocal changes are ST depressions seen in the leads pointing in the opposite direction of the leads that have ST elevations. A real life example of a full-thickness inferior wall MI, the overall "noise" vector ends up being pointed away from the inferior (downward) pointing leads (II, III, aVF), so you see ST segment elevations in those inferior leads (II, III, aVF). Instead of looking at that overall "noise" vector as pointing AWAY from the INFERIOR direction, you can say that the "noise" vector is pointing TOWARD the SUPERIOR direction. Therefore the ECG waves in the leads pointing upwards in the SUPERIOR direction (I, aVL) will show ST depressions. You'll notice that lead I is not actually pointing downward (it's rather pointing horizontally) but still shows ST depression in this case since likely the "noise" vector in an inferior wall MI is pointing away from somewhere in between leads III and aVF (not exactly pointing downward 90 degrees). Hope that helps clear that up?

[@chrispeters5194]

My ecg said mild st elevation and the ecg before that said poor r wave leads 2 and 3. Is this bad ?

[@medrounds101]

Hi! I unfortunately can't really comment on that, and I'm definitely going to defer that to your physician. ECGs have to be interpreted along with the overall clinical picture, and unfortunately, it wouldn't be appropriate for me to give any evaluation (i.e. good, bad, etc) on your ECG.