12 Lead ECG Explained, Animation

(USMLE topics, cardiology) Understanding the standard 12-lead EKG - Basics of electrocardiography explained.
Purchase a license to download a non-watermarked version of this video on AlilaMedicalMedia(dot)com
Check out our new Alila Academy - AlilaAcademy(dot)com - complete video courses with quizzes, PDFs, and downloadable images.
©Alila Medical Media. All rights reserved.
Voice by: Sue Stern.
All images/videos by Alila Medical Media are for information purposes ONLY and are NOT intended to replace professional medical advice, diagnosis or treatment. Always seek the advice of a qualified healthcare provider with any questions you may have regarding a medical condition.
Electrical activities of the heart can be picked up on the skin via electrodes. An ECG machine records these activities and displays them graphically. The graphs show the heart’s OVERALL electrical potential, or voltage, as it changes over time during a cardiac cycle.
The 12 leads of the ECG represent 12 electrical views of the heart from 12 different angles. The conventional 12-lead procedure involves attaching 10 electrodes to the body: one to each limb and six across the chest.
There are 6 limb leads and 6 chest leads.
The 6 limb leads look at the heart in a vertical plane and are obtained from three electrodes attached to the right arm, left arm, and left leg. The electrode on the right leg is an earth electrode.
The measurement of a voltage requires 2 poles: negative and positive. The ECG machine uses the negative pole as zero reference. Thus, the position of the positive pole is the “point of view”, and the line connecting the 2 poles is the “line of sight”.
Leads I, II, and III are BI-polar - they measure electrical potential between 2 of the 3 limb electrodes: Lead I represents the voltage between the right arm - negative pole - and the left arm - positive pole, and thus looks at the heart from the left. Lead II sees signal movements between the right arm - negative - and the left leg -positive - forming the INFERIOR LEFT view. Similarly, lead III measures electrical potential between the left arm - negative - and the left leg -positive, looking at the heart from an INFERIOR RIGHT angle.
Leads aVR, aVL, and aVF, or “augmented limb leads”, are UNIpolar. They use ONE limb electrode as the positive pole, and take the average of inputs from the OTHER two as the zero reference. Hence, aVR looks at the UPPER RIGHT side of the heart; aVL looks at the UPPER LEFT side of the heart; and aVF looks at the INFERIOR wall of the heart.
The chest leads, or precordial leads, view the heart in a HORIZONTAL plane. These are unipolar leads. The corresponding chest electrodes serve as the positive poles. The reference negative value is the same for all chest leads and is calculated as the average of inputs from the three limb electrodes.
DE-polarization TOWARD a lead produces a POSITIVE deflection; DE-polarization AWAY from a lead gives a NEGATIVE deflection. The REVERSE is true for RE-polarization. Thus, leads that look at the heart from different angles may have waves pointing in different directions.

[@Alilamedicalmedia]

Love this video? Check out our ECG/EKG course made entirely with videos like this (no watermark, no ads): Students, click here: www.alilaacademy.com/courses/ecg-ekg-for-students Teachers, click here: www.alilaacademy.com/courses/ecg-ekg-for-teachers NEW: Now you can also get access to our courses with our KZbin channel membership (Academy Access levels)

[@tracyflood1194]

This video is good for understanding leads (views) Remember, leads are NOT electrodes. A lead is a certain perspective or view of the heart function. An electrode is the physical tool📷 used to provide the view. That’s why 10 ELECTRODES can provide 12 LEADS🤯

[@tracyflood1194]

@@bling1349 that one concept slowed my understanding at first!

[@bling1349]

@@tracyflood1194 Ikr

[@disturbia1378]

Small but super important thing to keep in mind!

[@muhammadhamza2561]

Amazing point de🌷

[@hebaahmed3792]

Thank u

[@rebekahjaquez9973]

I was hopelessly lost until this video. Thank you so much!

[@abbyhagen94]

perfect video for anyone who needs a quick refresher! probably not the best video to learn this for the first time

[@pamelachua2651]

Why did I read the textbook for 3 hours and still not understanding much while this video explains everything perfectly in 3 minutes

[@rub9729]

me tooo

[@Asantewarrior]

work smart, not hard

[@sakthivelb9074]

@@jelleleeuwis4353 lol 😂

[@ericaj4016]

Wow! This really helped me. My professor is expecting us to know this, and I thought it was super difficult till I looked at this video

[@ChrisNP87]

Thank you for explaining this as easily and clearly as possible! I finally get it!

[@SyedUbaidullahShah]

Didn’t even understand this from DR NAJEEB. U r ECG saviour!!!❤

[@raniabrahim46]

sis just explained an entire chapter in 3 minutes damn

[@Alilamedicalmedia]

Thank you for watching! Follow us on Twitter twitter.com/AlilaMedical for instant notification of our new videos!

[@DKexoriente]

All of your videos explain complicated things so clearly they start to seem easy, thank you so much for your work!

[@Alilamedicalmedia]

Thank you for your comment.

[@AbuTaher-eh1is]

A very details explanation within very short time.Thanks a lot.

[@Mel-iy5ih]

best video ive seen to study how to place the leads

[@saraaMoh]

I still don't get it

[@siddharth5186]

lmao same here

[@soulwreckedrsps5882]

Same here one of the most complicated shit ever 😂

[@JoseGarcia-ww1bn]

ist just the most complicated part

[@abdulbasetaziz3829]

Same

[@doctork7003]

Totally!

[@jo-anncintron6234]

Thank you so much for sharing. I have such a hard time understanding it through lectures, bc I’m more of a visual/hands on learner with repetition. I don’t have to watch the video again bc I understood it the first time....

[@FBWUniverseMode]

It doesn't explain the topic entirely, there's no physics standpoint explanation nor how to read the diagram smh.

[@akashbaburaj2349]

Big thumbs up for the team of alila media

[@VFamily-jf6eh]

Its amazing how this machine can capture so much.

[@PumpkinQueen1393]

Easy to understand, well put. Learned more in this 10 min video then I did in two whole classes! Ty!

[@deepakmanoharan9045]

wow, great work compiling this educational animation

[@yousoro2876]

Thank you so much, I finally understand the leads!

[@middleearth4841]

That was amazing! I finally understand it now!

[@sushantkumar9211]

thank you for this short but very useful video

[@nervot7464]

Thanks its mutch better now

[@SubarnaDasxD]

Thanks for such lovely explanation

[@amberjohnson6483]

Awesome! Effectively, and precisely explained

[@curtpiazza1688]

Good info in such a brief video!

[@doctork7003]

It is entirely my fault, but I was lost at 00:30

[@yangsi3389]

Really thankyou so much.... Very helpful ✨

[@shibulinabraham6435]

You guys are simply awsum .....keep rocking ....⚓️💝

[@Jana-ne6km]

awesome*

[@d4_smt4_idewaputuarviandan41]

thanks your video is helpful for me

[@Muhamm4d_MD]

Actually excellent vedio , give more information from little time, thanks i hope continuoe

[@kosayen2]

What do I need to do in order to understand this video fully? Should I review some of school textbooks?

[@tnwhiskey68]

These comments all seem fake..

[@twaseempm2336]

Excellent video class

[@user-shalalala]

This really helped , thank you

[@draishwaryaa8242]

very precise & helpful

[@DrSavitha-z2y]

Very informative

[@BREAKKtheTEETHoftheWICKED]

Good video!

[@user-sq3ls6sj7i]

Thank you!

[@ياسينحمداحمد]

Excellent video .thanks but I need pdf for words in video 🇸🇾

[@savagedan3474]

Thank you so much for savin ma life

[@shristidas7977]

You got my heart❤️❤️❤️

[@murukeshtimetvm4119]

Thank you so much ❤️❤️❤️

[@gregfeneis609]

10 electrodes to capture 12 signals of interest, referred to here as leads.

[@marg716]

Nicely worded. I can remember asking so many people “How can we get a 12 lead EKG when I only have 10 leads (wires) to attach to the patient?”

[@mohatik1421]

Very helpful !

[@AmitisL]

Very helpful , thank you so much

[@shajibkhan8465]

Really awesome.....

[@MichaelTorres-bc8mi]

Her voice is equivalent to nails on a chalkboard

[@shivalikarmali8105]

Thank you so much

[@alisalama4323]

Thank youuu so much 👏❤

[@Alilamedicalmedia]

You're welcome 😊

[@반짝반짝7]

thank you~~ 2:47

[@saraibrahim7578]

Thank you🌸

[@BagiBagiInfo]

Thanks thanks thanks for it..

[@BoAnggg07]

What are the books or references your using?

[@AbdulWahab-on8om]

very wll explained

[@ologhomaie5837]

Thank you ❤❤🤗

[@moslemseyedzade2868]

Awesome video tnx

[@ashalavylo]

Amazing!

[@safiyakamila7488]

Thank you very helpful.

[@iiiivvvv9986]

Watching this the day before exams cause I forgot the tutorial on this

[@matthewgregory2106]

Thank you

[@danspitalnik]

So helpful. Thanks.

[@fakhruddinmasse2223]

Hello. thanks for the video. Some of the questions, are: - Is negative electrode always the zero reference for ECG measurement. I didn't find any explanation regarding this in textbook/essay. Please help me to find if anyone has read it - Some books noted that the negative electrode is located at central terminal (which located in the center of the heart). But in this video, for example, the negative electrode located between 2 electrode (i.e., augmented lead) I just need the supported references for my better understanding. Thanks

[@tmsff9893]

Did you know the answer.?

[@jonen9494]

This is gold

[@user-ec1uy8jl3i]

Very thanks ♥️♥️♥️♥️♥️♥️♥️♥️♥️

[@alialrawi4832]

Thank you very much 😊

[@Anandpandu774]

very gud 👍

[@ceegrizzley]

This helped me so much!!

[@muhammadtufail3323]

owsum i got what i wanted to

[@usmleLION]

The labeling of lead II and III is somewhat confusing, as the II is on the right, and the III is on the left. 1:45

[@l3MTA3l]

So the Right leg electrode is an earth electrode. So where's the AVE lead on the 12 lead tracing? Will see Squiggles on the AVE lead if there's an earthquake?

[@sachinphilip5446]

Good one

[@citytalkwithDJTOR3LL]

So to understand this videos try to understand the meaning of; Electrode, limb leads and voltage.

[@omeshwaribasena4280]

Thanks

[@maimohammad152]

Omeshwari Basena ;

[@FBWUniverseMode]

why didn't you continue to explain, I was finally understanding everything and you stopped where I have problems, how the final diagram works, and how to read it!??

[@Alilamedicalmedia]

Those are covered in other videos, you can check them out in our channels.

[@FBWUniverseMode]

@@Alilamedicalmedia omg! Thank you so much!!!

[@Itzz_Eyelashes]

Why we don't use right leg for attachment of electrode instead of left leg ???

[@amritrimal4817]

Am i the only engineering student here, who is watching it for instrumentation`s presentation?

[@zaeidalhamashi8548]

well done :)

[@TheRisingKarma]

How about discussing ECG in detail in next video.

[@Alilamedicalmedia]

Yes it's on our list!

[@rwndmajal5383]

+Alila Medical Media hi

[@rwndmajal5383]

+Alila Medical Media i study about the lead but i dont under stand the uniploer wt is

[@Alilamedicalmedia]

It's explained in the video, you may want to turn on the "CC" button for subtitles to understand better.

[@AnilP-ll7kd]

Wow 🤩

[@rockyruane9379]

Can a right bundle branch block ever be normal? Or is it always serious?

[@apachette07]

So....12 lead EKGs are used to assess the function of the _______.

[@analogaudiorules1724]

Where do you get your information, what references?

[@vintotschannel4616]

How may hours is the test done?

[@Anyonewho87]

love you

[@Rob-pg7zx]

If you are looking at the heart from a transverse view, does that mean you are looking at the heart from above, i.e. bird's eye view?

[@vikramjeisurya6324]

nice

[@Kennerdoll]

So if I get my multimeter and measure voltage(probably some DC mV) between R(Neutral) and L(Live) i'm suppose to get some volatge right? #Just_Curious

[@MedEasyAnas]

What is zero ref?

[@Alilamedicalmedia]

The background level that is considered zero. Similar concept = tare in weighing

[@MedEasyAnas]

Thank you!@@Alilamedicalmedia

[@khalidsaud2792]

How is the same place as right arm can be positive and after that can be negative???? Please answer me

[@gulzarwani1179]

Right arm is negative always,it is actually the axis of lead u have to understand.for example lead 2 has negative at right arm and positive left leg.axis of cardiac depolarization is 59 with positively​ charges moving towards left leg..Hower axis of avR is vertically down ,i;e, right angles to lead 1.so its negative isn't right limb, but the point where mean of the right limb and left limb is zero.it is not necessary it should be negative.as you know charge with +2 units negative with respect to charge of + 10.as charges will flow from higher charge concentration to lower charge concentration till equilibrium is established.Further in heart there is propagation of depolarization. To understand it fully u should understand vectocardiogram.U r welcome to ask where u need,so that I can get rid of any possible confusion

[@dylanfitch2997]

As good as Dubin put it!

[@pietervanheste]

What is the difference of the line of sight and the view?

[@ishukhneja]

can anyone tell what's the meaning of depolarization towards the lead?

[@rawanasaad2466]

Why the view from RA to LL is left view

[@aleenazahid7016]

If 1 lead across each limb then 1×4=4 6 across chest then 4+6=10 Then how can be there 6 limb leads Can anyone explain, I have exams tomorrow 😒

[@Abu.99rami]

Every single wave mean one

[@sandragonzlz]

Why is Moira Rose narrating this video

[@Departedreflections]

you 200,000 views and 35 comments - common :P

[@simplyeason]

how come sometimes the leads on the two shoulders are placed at the wrist? and im still confused on where i should be placing the leads on the legs.

[@TheSanureta]

yes logically you feel that you should place the lead on the shoulders and at the lower limb junction but guess what if you put it on the shoulders or the wrist the result will be the same because the electricity will be the same

[@telepcanin2878]

How do you decide which electrode is positive/negative, what is substantial physics behind it

[@Alilamedicalmedia]

In physics the flow of electrons is toward the positive electrode. Here, however, it's by convention - the negative electrode serves as zero reference for the positive.

[@محمدعماد-غ3ظ6ظ]

وحق الله اخر شي