ECG: The augmented limb leads aVF, aVR and aVL
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- Опубліковано 28 вер 2024
- We show how to record the augmented limb leads of the ECG. This is done by using two resistors which join two limbs together and then connect to the negative input of the amplifier. The positive input of the differential amplifier is then connected to the remaining limb and so on. This gives us aVF, aVR and aVL. With the resulting aVF it is then very easy to estimate the mean electrical vector of the heart which is also demonstrated in this clip.
Presenter: Vasso Georgiadou
biosignals.bern...
Good question! What you want is adding the two voltages numerically from the two limbs. You get an ideal adder when the input resistance of the amp is very high against the resistors and the resistors are identical. The electrode resistances add to it so the two resistors should be high compared. However the diff amp would love to have low resistances so that the 50/60Hz on + and - is identical. Traditionally it's been around 5k but could probably be up to 100K to improve the computation.
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Wow. Now I get how the avr, avl, avf. I want to learn to read them independently. It be nice
eyebrows are really expressive 😍😍😍
Very helpful, thank you!
Those were the Goldberg's circuit?
thanque U ARE BEST THAN MY TEACHER AND U R BEAUTIFUL TOOO
what are the resitors 1 & 2 value @ 1:50 min into the presentation?
How would you hook a 5 lead ecg cable to the bio-amplifier?
Thanks, great learning tool!
Thank You
Thank you very much ❤️🔥🌺
Yes, the lecture said augmented vector.
+Mark Younger ...but the vector is in volts... ;)
Augmented leads introduced by gold berger
how many ohms are those resistors?
5K or perhaps more. The idea is to calculate a potential average so in theory a very large value will do that perfectly but because the differential amplifier has an input resistance there are limits till you lose the signal. I'd reckon with modern amplifiers that can be much higher. However, in modern ECG machines only two Einthoven channels are measured (for example II,III) and and then you can rather calculate aVR,aVL and aVF from it. Einthoven won't require any resistor magic so much easier.
5000ohm it use because in our body the triangle formed by those 3sides ie rt arm left arm and left foot is not an equilateral triangle so the mid point is not going to zero potential... Actually it is near zero potential in order to avoid that we put those registers
Exillent
It is augented Voltage, not augmented vector according to my professor..
Ur facial expression are so cool
The "V" in aVR, aVL, and aVF actually stands for voltage and not vector. It could though, if it had been named that way but it wasn't
+Mark Younger yes of course! Did we say something differently?
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Girl them eyebrows
girl your eyebrows
lmfao was thinking the same. about to lift off the face
Impressive
Thank you
How does connecting through two resistors to a negative terminal create a virtual lead at center point of the two leads? Please explain in simple terms, Thank you
As far as I know, she is an actress and she can explain it clearly as she was an academics.
Although my language is so sick I understood 😂
She had me at Hello!
i understand now thank you
Would it be the same if you placed real electrodes on top of the thorax, in the places represented by the virtual leads? In other words, the only advantage of this set up is using less electrodes? But could you retrieve the same information with bipolar leads? I'm trying see if I understand it conceptually since I have no background in engineering, I'm a med student. Thank you!
thank you
great explanationn!!!
Thankyou 🙏
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Hello. Please what does it means to have an abnormal aVF. What is the significance
She's cute and very helpful!
I wasn't being critical, it was a good presentation. I liked it a lot.
+Mark Younger Thanks! :)
+BPM biosignals ...and thanks for the feedback.
Wonderful
Strong work!
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Why you do like chewing something ....it's just irritating bet your good lecture.