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1/
 Ever wonder why a "STEMI" causes ST elevation on EKG?

The answer is mind-bending.

#medthread #tweetorial #medtwitter
2/
 We need to review a few basic EKG facts.

First:
💡 If electrical signals travel away from an EKG lead they appear as negative deflections
💡 If electrical signals travel toward an EKG lead they appear as positive deflections

bit.ly/2PIRGWw
3/
Second:
Recall that the ST segment represents electroneutrality in the cardiac cycle, between depolarization and repolarization, w/ no voltage gradient.

That's why the ST and TP baseline segments are normally flat on EKG (aka isoelectric).

bit.ly/2PGiLJZ
4/
 There are many channels that contribute to ventricular repolarization.

An important one is K-ATP, a potassium exporter channel that needs adequate ATP to remain closed.

Less ATP available = more potassium export from the myocardial cell.

ncbi.nlm.nih.gov/pubmed/9349389…
5/
 Not surprisingly, during ischemia mitochondrial ATP production goes down.

physiology.org/doi/full/10.11…
6/
 This decrease in ATP production leads to more potassium export through K-ATP ➡️ faster ventricular depolarization of ischemic cells relative to healthy ones➡️a shorter cardiac cycle.

physiology.org/doi/full/10.11…
7/
 Here's another way to view the shorter ischemic electrical cycle. 👇

physiology.org/doi/full/10.11…
8/
 This difference in cycle speeds between ischemic and non-ischemic cells causes a relative current during repolarization:

Ischemic➡️non-ischemic, away from overlying EKG leads

This shifts the EKG baseline down, for reasons we discussed above.

bit.ly/2s99b9l
9/
 Conversely, there is little difference between ischemic/non-ischemic depolarization speeds.

Thus the voltage gradient disappears during the QRS complex and the EKG returns to isoelectric baseline in the ST segment (aka zero voltage).

bit.ly/2s99b9l
10/
 The ischemic ST segment therefore appears elevated on EKG, but only because the baseline has been shifted down.

bit.ly/2s99b9l

👇
11/
 Let's summarize:
💡Ischemia➡️decrease in ATP production
💡This➡️K export and faster depolarization
💡An ischemic➡️non-ischemic current is created, lowering the EKG baseline
💡W/ depolarization, the gradient stops➡️ST segment = isoelectric
💡This = appearance of ST elevation
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Avraham Z. Cooper, MD
@AvrahamCooperMD
1/
 Ever wonder why magnesium (Mg) is used to treat Torsades de Pointes?

The answer is fascinating, elegant, and also explains why Mg treats another clinical entity - eclampsia

#medthread #tweetorial #medtwitter
2/

First, let's find how torsades was originally described (and named!):

💡Francois Dessertenne noted "ventricular tachycardia with two variable foci" in a patient in 1966
💡He coined the arrythmia torsades de dointes, connoting "twisting peaks"

bit.ly/2XN9Hp5
3/

To understand how Mg treats torsades we need to understand the pathophys of the arrythmia itself.

▶️Torsades is a ventricular arrythmia of repolarization, occurring in patients with prolonged QT intervals (usually acquired from drugs, ischemia, or⬇️electrolytes)
Read 15 tweets
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Avraham Z. Cooper, MD
@AvrahamCooperMD
1/
 Have you ever wondered why patients in shock are refractory to vasopressor support if also severely acidotic?

I always assumed it was b/c cellular stuff just doesn't work well at low pH.

It turns out the answer is slightly more complicated...

#medtwitter #tweetorial
2/
 First we need to establish if acidosis actually leads to vasopressor resistance.

This was first described in 1927 in an experiment involving pithed cats:
- The researchers increased/decreased their respiratory rate to change serum pH
- Responses to vasopressors were measured
3/
 Lo and behold, the cats with a lower serum pH had diminished blood pressure responses to vasopressor injection (they used epinephrine).
Read 15 tweets
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Avraham Z. Cooper, MD
@AvrahamCooperMD
1/
 Many think that Van Gogh was "dig toxic" and that it impacted his vision and painting. Was that really true? This #tweetorial explores whether the great artist was actually toxic on digitalis.

#medtwitter #FOAMed #meded #medicalhumanities
2/
 First, we need to understand a couple of things:
▪️What ailed Van Gogh?
▪️How can digitalis affect vision?
3/
Many diagnoses have been applied to Van Gogh, from lead poisoning to porphyria.

Most historians believe his depression, mania, and convulsive episodes indicate:
⭐️Schizoaffective disorder
⭐️Epilepsy
Both of which were made worse by absinthe.

ajp.psychiatryonline.org/doi/full/10.11…
Read 13 tweets

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Simon Tobin
@DocRunner1
1/16
Ever wondered why doctors and people with type 2 diabetes are getting so excited about low carbohydrate diets? 🤔

73 patients at my surgery have now reversed their type 2 diabetes 🙌

#medthread #tweetorial #medtwitter

Here's a tweetorial of how it's done👇
2/16
As Diabetes Lead GP at my surgery for 25 years I achieved little/no success with @PHE_uk recommended "Eatwell Plate"
One day @lowcarbGP shared some success he had with offering LCHF (low carb, healthy fat) eating to people with type 2 diabetes

Does it work?🤷‍♂️

How? 🤷‍♂️
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Important to understand if there's > 1 teaspoon (5g) sugar/glucose in your blood then insulin PUSHES it into cells where it is deposited as FAT and TRIGLYCERIDE
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Greg Irving
@gregjirving
1/
Ever wondered about the evidence base for longer [or shorter] GP consultation lengths and how they impact on healthcare outcomes?⏱️

The evidence is fascinating and well worth considering in relation to your own practice.💡

#medthread #tweetorial #medtwitter
2/

First, lets take a look at average consultation lengths around the world.

⏱️ There is considerable variation internationally ranging from less than a minute in Bangladesh and Pakistan to 22.5 minutes in Sweden!
3/

🌍Over half the worlds population have a consultation length less than 5 mins!
Read 19 tweets
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Depth of Anesthesia
@DepthAnesthesia
1/ Tweetorial alert 🚨🚨

Why does propofol burn so much?

It turns out the answer is not what you might expect. We'll cover some literature exploring the question and some evidence-based strategies to prevent it.

#Tweetorial #medtwitter
2/
Propofol was developed by John Glen, a veterinarian and researcher at the Imperial Chemical Industries. Yes, that's him down there.
3/

Propofol was originally formulated with a castor oil (Cremophor EL).

This formula was withdrawn due to anaphylactic reactions and re-formulated into a soybean emulsion.
Read 19 tweets
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Steven Chen
@DrStevenTChen
Bit of a different #tweetorial today, on:

CONSULT ETIQUETTE!

- TIPS for the PRIMARY TEAM calling the consult.

Caveat: Some examples are a little #dermconsult specific, but can be extrapolated to others!

#medthread #dermtwitter #medtwitter #meded #FOAMEd #tipsfornewdocs
1/
As both a #dermatologist & a #hospitalist, I have the pleasure of being on both ends of the #consult game.

So, your team has decided to call a consult, and you are the intern or student who has been tasked with contacting the team. Don't be nervous! Try these tips!👇👇👇
2/
First of all:

1)Have a consult question

Asking a consultant to see a pt w/o a ? is like having a pt see you w/o a chief complaint! The ? helps the consultant frame the note in a way that is most helpful for you & your team. Otherwise, I'm guessing at what you want to know.
3/
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Avital O'Glasser, MD FACP FHM
@aoglasser
Friday #Medthread! I’ve been chatting lately that I should write a #tweetorial about how I’ve put my social media related/based activities on my academic/professional CV. So, without further ado... 1/x
these are excited times, & hopefully this won't be uncharted territory for too much longer as standards are set and more institutions embrace social media related activities...BUT for now...how do you show your uniqueness and innovations via #medtwitter #SoMe?? 2/x
Disclaimers:
1⃣these are my opinions (grounded in experience & many discussions)
2⃣I use the OHSU CV template (Scholarship/Service/Teaching)
3⃣employers may not be ready to embrace

PS--bonus points--name the TV show the GIF is from!! (probably not known/respected enough...)
Read 18 tweets
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Tyler Larsen
@TylerLarsenMD
1/ Why are EKG waves named starting with the letter P? What happened to letters A through O?

I’m guessing you’ve probably never wondered this, but if you’re curious, here’s a brief historical #medthread / #tweetorial on how the EKG waves got the names they did.
2/ The first electrical tracings of the heart were obtained in 1887 by A.D. Waller, a British physiologist and physician, who used a Lippmann capillary electrometer to capture the tracings.

ncbi.nlm.nih.gov/pmc/articles/P…
3/ As a physiologist, Waller labelled the two waves on his initial tracing V1 & V2 based on their site of anatomic origin- the ventricle. He would continue, often rather adamantly, to refer to the electrical waves as A, V1, & V2 throughout his career.

sciencedirect.com/science/articl…
Read 11 tweets

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