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The T wave
The T wave is essentially the Schrödinger's cat of the ECG.
You can be sat there, minding ̶t̶h̶e̶ ̶f̶l̶a̶m̶e̶s̶ your own business, when a patient comes in with weirdness in their chest.
You have no idea what that ECG is going to show you.
Will it be normal?
Will it be abnormal?
Will it be abnormal, but normal for the patient?
Is it a child and therefore you accept juvenile T wave patterns?
...Do you even know what juvenile T wave patterns even are?
All these intrusive thoughts can swim around in the air and nobody knows what we're going to find until we open the box, put the leads on and see what we find.
A sample of such possibilities are as follows:
What does the T wave represent?
Since we've established that the "T" (as in "temperamental")wave, can be a sign of all signs of badness and mischief, it is worth highlighting that the T wave represents ventricular re-polarisation.
With a brief detour back to A-level biology, the reader will be reminded about action potentials, and how biological cells rely upon chemical ions to generate them.
The humble cardiac myocyte which never tires (until it does...) also has its own action potential graph, an example of which is as below:
At one point in my life I could regurgitate the above for exam purposes.
The take home point is that various ions are needed for this action potential to function correctly, and indeed various ion channels are needed for it to function correctly.
When channels do not function correctly, be it congenital like "Long-QT Syndrome" or acquired such as TCA overdose, then weirdness occurs on our ECG because, shock horror, the electrocardiogram is detecting electrical changes.
Therefore, the T wave is markedly sensitive to such wierdness, such as the eponymous "tall tented t waves" of hyperkalaemia.
(The patient's literal presenting complaint was: Unwell, palpitations)
Food for thought:
(Why some syndromes have super logical names as opposed to the usual unpronounceable ones like Creutzfeldt-Jakobs, is unknown. On the other hand, the author is also aware that having an ultra-german approach to naming things ends up with conditions like pneumonoultramicroscopicsilicovolcanoconiosis.
(No, i did not make that up. Feel free to google it.)
As a starting point for the beginner however, they simply need to remember that under normal circumstances, the T wave should be relatively smooth, and
+ve in all leads
except
for aVR and V1.
This is seen in our well flogged example paramedic ECG:
For the sake of keeping things simple, I will acknowledge but not go into the fact that "normal variants" exist. It is good enough at this stage to bring out a quote that describes myself and my job.
I am an Emergency Physician.
I am sensitive.
I am not specific.
Next: The QT segment
The most unrealistic part of this generated image is, of course, the fact that the individual is wearing a watch (as opposed to the fact AI cannot spell). This is absolute heresy against infection control.
The fact that mandatory training on the subject is about as useful as the dosimeter depicted is unrelated. )
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