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Heart disease and heart attacks | Miscellaneous | Heatlh & Medicine | Khan Academy

March 12, 2020

I think most of us know what the heart does in our body. It pumps the blood and in particular it takes in the blood from the rest of the body. That is blue over here in this diagram, because that blood does not have carried oxygen And it pumps that blood to the lungs where the blood gets oxygenated. And then it comes back from the lungs, depicted as red blood, now that it has oxygen in it. And then that oxygenated blood is pumped to the rest of the body. And I think also, most of us have the general idea that when people talk about heart disease or heart attacks, which we learn, are two different things, related but different things, that has something to do with the clogging of arteries. so when I was a kid and I first learnt about the clogging of arteries. and I knew enough that the heart is all about pumping blood to the body. I assumed the artery that people were talking about these big arteries that were coming away from the heart to the rest of the body that somehow these things got clogged up. so let me draw that, different colour you can see so this was my ….this is what I thought people were talking about when they were saying clogging of the arteries and maybe when they got clogged enough, the stopped blood flow to the rest of the body somehow and that would actually kill the person. I want to make it very clear right now. Those are not the arteries that people are talking about getting clogged, when people talk about heart disease or heart attacks. The arteries that they are talking about are the arteries that actually provide blood to the heart. Remember the heart itself is a muscle. It itself needs oxygen. So you have these arteries right over here, the red tubes. Those are arteries. and then the blue ones are veins. They’re taking the de-oxygenated blood away from the tissue of the heart. And these are called coronary arteries. And this one over here at least from the point of view of me or you looks like it’s on the right. Or from the point of view of the person whose heart it is, it’s on the left. This right over here is called the left coronary artery or LCA. And this right over here in red is called the right coronary arteries or the RCA. And so when people talk about arteries getting blocked or getting clogged, they’re talking about the coronary arteries. They’re talking about the things that supply blood to the heart. So let’s zoom in on one of them….Maybe we can zoom in right over here, that part of the artery. That’s the tube….clear where I am zooming in. I am zooming in right over here. So over time, I am not going into the details how this happened. It is subject for another video. You can have these plaques build up along the walls of the artery. So over time if a person doesn’t have the right diet, or maybe they just have a predisposition to it, you can have these things called plaques form on the walls of the arteries. And the plaques, the material inside of them are lipids, so things like fat, cholesterol and also dead white blood cells, which is this kind of messy substance right over here. This is what we call a plaque. And the formation of these plaques that obstruct the actual blood vessel, that actually obstruct the artery. We call it…..make it clear you see that. This is kind of tube over here. Let me draw the blood So this formation of these plaques we call atherosclerosis. So you can imagine if you have these things build up, it’s narrowing the actual vessel that’s supplying blood downstream from that obstruction. So it would be destructing the blood flow downstream right over there. In that general process we talk about the restriction of blood flow, that is ischemia that’s happening. So ischemia is deprivation of blood flow and oxygen downstream from this right over there. That’s what we call coronary artery disease, or heart disease. So this causes coronary artery disease, which is sometimes called heart disease. Coronary heart disease would be redundant, because coronary is already referring to the heart. This is also sometimes called heart disease. And so you can imagine if downstream the muscle tissue is not getting all the oxygen it needs, especially maybe when this person, whoever’s heart this is, when they are exerting themselves, they need more oxygen. The heart needs to pump a little harder. If downstream the cells are not getting all of the oxygen they need, you can imagine that the heart maybe not able to provide all of the functions, whoever’s heart this is, that they needed to do. And when that happens that’s called heart failure. So heart disease is one of the causes of heart failure. Now I want to be clear, heart failure does not mean that the heart is stopping. That the heart is stopped and the person is dead, it literally just means that the heart is failing to do what it should be doing. It’s failing to provide the needs of that person. So it’s not pumping hard enough or well enough to provide adequate function for that person. The other symptom that actually might occur when someone has coronary heart disease, where they have obstruction or this ischemia or this deprivation of oxygen downstream from this obstruction, is that they might experience this kind of strangling chest pain That’s called angina pectoris or sometimes angina. Very few people say the pectoris part. Sometimes you hear people say oh angina. Angina pectoris, which is really chest pain, angina literally comes from meaning this kind of strangling feeling, and pectoris is in the chest. This is strangling feeling in the chest. This is a symptom of heart disease. Now this is already not a situation you want to get into because already your body is not able to function as well as it maybe could be, as maybe it could. Sometimes as I might describe here is a plaque. Some plaques are actually unstable. These plaques just grow and grow and grow. It makes probably heart disease worse and worse, heart failure worse, and angina pectoris worse. These plaques are unstable. It can actually rupture. You can imagine all these blood flows, as plaque grows, the blood flows become a little turbulent around these plaques. It has to go really fast through this narrow section. It comes out turbulent on the inside and creates these friction and all the rest. At some point, you can imagine this plaque is unstable. It could actually rupture. Let me draw ruptured plaque over here….let me draw the same one….I am gonna draw the ruptured. Now this plaque has rupture. It got so big. Maybe the turbulent blood flow helped stimulate this and whatever else. For whatever reason, it ruptures. When it ruptures, now it sudden i am doing a simplification of the process right over here. Now the content of this plaque: the lipid, the cholesterol, the fat, the dead white blood cell. Now it sudden is exposed to the blood flow. in particular to the clotting factor in the blood. This is highly thrombogenic material. Thrombogenic, very fancy word. That just means, that tends to cause blood clot. Thrombosis is a blood clot. What happened is, as soon as this type of things happened, it can literally happen in seconds or in minutes. All the sudden you could have these clotting factors form a clot right over here right at the actual plaque. As this happens, it starts to really really really obstruct the blood vessel. Sometimes it can even completely obstruct the blood vessel. When it happens, you are significantly depleting the blood flow going downstream from there. You might even be shutting it off. When you do that, the cells downstream will no longer get oxygen. They will die. This right over here, is called an infarction. an infarct is actually a dead heart tissue. You can imagine when heart tissue begins to die, this is even worse than what we were describing with coronary heart disease. Not only coronary heart disease just is not getting enough oxygen, now they are actually dead. They are turning into dead tissue. This process of completely or almost completely depriving cells of oxygen so that they die, this is a heart attack. Let me completely obstruct this artery to make the point clear. this right over here is a heart attack. This is the primary cause of heart attack. It’s less likely but sometimes a plaque could also go downstream, kind of form a thromboembolism. It would be this thrombogenic material, the clots around it. It would actually go and block the artery further downstream and be embolism. That can also block the artery and cause tissue to die. But the main cause is this intense clotting that can occur pretty quickly and completely obstruct the artery. There is one last word i want to touch sometimes mixed in with all the other words, that is cardiac arrest. That’s because sometimes we use them in the same context. one thing can lead to another. Heart attack is not cardiac arrest. Cardiac arrest is the actual dying of the heart. What I just described in a heart attack, people can have a heart attack. They will have some part of their muscle tissue die. Some part infarct, that’s what they called myocardial infarction. Myocardial means the tissue of heart or the muscle of the heart that’s dying. Sometimes it is called myocardial infarction. That is not cardiac arrest. Cause you can have some of your heart tissue die and you can survive. Your heart would be impaired. But you will continue to live. Cardiac arrest is literally your heart stopping. This would obviously cause someone to die. If you have a bad enough heart attack, if you have enough of the tissue get starved of oxygen so that it dies, infarction occurs. Then it could lead to cardiac arrest. It always won’t lead to cardiac arrest. Frankly, heart attack is not the only thing that can cause cardiac arrest. I also want to once again differentiate cardiac arrest from heart failure, because they sound the same, sound like heart is failing. Cardiac arrest is heart stopping. Heart failure is essentially just saying that heart can not provide all of the needs for the body.


  • Reply mohalfur August 2, 2011 at 2:36 pm


  • Reply Quantum Custodian August 2, 2011 at 2:48 pm

    Remember kids, dont shock the flat line !

  • Reply Дима Маталинов August 2, 2011 at 2:58 pm

    thank you Khan! Your enthusiasm inspises me learn sсience. So many themes on your channel, so many answers in your videos. Keep up the good work!!!

    P.S. I think that it would perfect if will make subtitles on other languages.

  • Reply Arcey Yu August 2, 2011 at 2:59 pm

    i love you 😀

  • Reply paavohalo August 2, 2011 at 2:59 pm

    The artery pointed as LCA in this video is actually the left anterior descending artery (also called LAD) to be presice. LAD is a branch of left coronary artery (LCA). LCA is only a short artery that bifurcates and gives rise to the LAD and so called LCX (left circumflex artery).

  • Reply zoroluva August 2, 2011 at 3:05 pm

    Dude! I just felt my heart cower in fear.

  • Reply Gzorz August 2, 2011 at 3:48 pm

    @rectodrn teaching you spelling.

  • Reply Mike Suopys August 2, 2011 at 4:06 pm


  • Reply Clea H August 2, 2011 at 4:50 pm

    You need to make more videos like this!

  • Reply Jerry W August 2, 2011 at 4:51 pm

    @gemini88miller similar how? it's possible that they would feel similar pain wise, but cramps aren't caused by any of the same problems that cause heart attacks

  • Reply Badar Alamri August 2, 2011 at 5:05 pm

    So the question is why only the arteries in the heart have this problems, why not my leg, hand , itc
    why only the heart ???

  • Reply apricotsnms516 August 2, 2011 at 5:14 pm

    ….Excuse my ignorance, but if this can happen to your heart, why can't it happen to anything? Such as a thumb attack? Does plaque not form anywhere else?

  • Reply Blooblop August 2, 2011 at 5:18 pm

    So confusing @[email protected]

  • Reply Jrf2112ROBLOXStyle August 2, 2011 at 5:32 pm

    @apricotsnms516 Im guessing that these clogs don't form instantly. Most of the blood goes through the heart, so most of the excess fat clings to the side of the arteries, causing it to build up over time. Very little blood goes to the thumb, so it's rare that that will happen. Although, there are attacks on other parts of the bodies. A stroke, for example, is a brain 'attack'.

  • Reply Hinz Zimmler August 2, 2011 at 5:35 pm

    @lesleyhenriquez How is that possible? the guy you mentioned must have been Obese. I'm 31 and i am slightly overweight. So far, no heart problems.

  • Reply Hinz Zimmler August 2, 2011 at 5:37 pm

    @Superbighenful Khan will not do that. He knows that English is the superior language. LOL NOOO SUBTITLES. make the non english people translate it themselves.

  • Reply superdau August 2, 2011 at 5:41 pm

    It does. If it happens in the brain, it can lead to a stroke. It will also happens elsewhere. I don't know if it's called like that in english, but there's something called "smoker's leg" (more generally "peripheral vascular disease"), which can even make amputation of limbs necessary.

  • Reply superdau August 2, 2011 at 5:42 pm

    It can happen in other parts of the body, but then it wouldn't be called heart disease anymore 😉

  • Reply Joe S August 2, 2011 at 5:59 pm

    Great video!

  • Reply Yahshua mySovereign August 2, 2011 at 6:17 pm

    I hope you are a Teacher. Thanks for your videos.

  • Reply Ci Madgeline August 2, 2011 at 6:49 pm

    can you do more videos on "pulmonary vein stenosis" or rather a video … especially in infants… please , thank you

  • Reply zsteele11 August 2, 2011 at 7:01 pm


  • Reply 42muslimah August 2, 2011 at 7:34 pm

    @Superbighenful actually, right now the khan academy folks are working on translating all the videos into tons of different languages. Check out Khanacademy . org 🙂

  • Reply brownmolasses August 3, 2011 at 1:09 am

    very informative…i learnt alot

  • Reply Devin August 3, 2011 at 5:07 am

    Fucking crazy guy right there. Easily could and become a doctor if he wanted, brilliant videos.

  • Reply Valdas August 3, 2011 at 8:00 pm

    What's the yellow part on the heart?

  • Reply chiyerano August 3, 2011 at 9:11 pm

    Mmmm, thrombogenic material. I learned a new word today. I am so used to hearing the term thrombosis. Thank you for this.

  • Reply Mattia Rosso August 10, 2011 at 5:41 pm

    You sure?Cause I'd have said it was connective tissue

  • Reply Harry Hall November 6, 2011 at 6:46 pm

    @khanacademy Is the infarction the heart attack or do heart attacks happen after an infarction when the heart is put under excess stress e.g. during exercise?

  • Reply Kimjongil3000 November 9, 2011 at 7:46 am

    very good video

  • Reply donkiko3000 January 17, 2012 at 3:00 am

    haha he has angina

  • Reply TheLandgoat March 12, 2012 at 1:55 am


  • Reply cappie2000 March 14, 2012 at 5:28 pm

    This video makes me wanna eat more healthy… this should be shown to everyone in school…

  • Reply Satchel Hogan March 19, 2012 at 2:10 am

    This is so cool!

  • Reply spencer carter March 20, 2012 at 5:53 am

    nitpicky, but the coronary arteries talked about at around three minutes are the LAD (left anterior descending artery, also known as anterior interventricular artery) and the right marginal artery. These are branches of the left and right coronary arteries.

  • Reply heyjack7 March 22, 2012 at 1:27 am

    8:50 you're s..s..screwed lol

  • Reply Patty Burdick March 25, 2012 at 8:47 pm

    Great Chanel

  • Reply João Louro March 30, 2012 at 10:51 am

    Your site came to replace 9gag for me. Thank you. Also, your voice is surprisingly clear. English is not my first language and I can still understand you perfecly.

  • Reply O C April 5, 2012 at 12:27 am

    Voice is pretty annoying, I can't follow this.

  • Reply Jonathan Thomason April 26, 2012 at 1:14 pm

    heart disease is clearded by application oh HIUS

  • Reply Nancy Corley April 30, 2012 at 3:04 am

    This is great!
    I love his voice too.

  • Reply Asmodai May 5, 2012 at 8:24 pm

    goddamnit why do u scare me like this

  • Reply JaceySquires May 14, 2012 at 2:06 am

    Hi Willow,
    arteries deliver blood away from the "chambers," the large interior spaces, of the heart. The coronary arteries DO go to the heart, but they supply the walls of the heart. They do not deliver blood back into the chambers. However, there are also veins, shown in blue on the image, which will drain the walls of the heart and send that blood back into the chambers. Hope that makes more sense for you.

  • Reply JaceySquires May 14, 2012 at 2:12 am

    Some of the yellow is fat tissue. It's normal to have some, but some unhealthy hearts will have a lot more.

  • Reply ahgoon69er May 24, 2012 at 11:00 pm

    exercise to not form the fat in blood vessel

  • Reply coolcurt4545 June 10, 2012 at 5:54 am

    I have chest pains and i went to the dorcrs and I dont have heart diseiase or heart failures what do I have

  • Reply ジンカム小野寺のオマンコ! June 25, 2012 at 3:08 am

    This video was so good, I had a heart attack.

  • Reply MarioMario24680 June 26, 2012 at 4:58 am

    No….. LET HIM BE YOUR DAD! 😀

  • Reply eatcarpet June 27, 2012 at 2:20 pm

    It's actually kind of scary what kind of damage it might be causing to your heart.

  • Reply james lee August 2, 2012 at 9:10 pm


  • Reply LadyHelena Ravenclaw August 14, 2012 at 3:38 am

    hehe Angina

  • Reply jNe4l August 24, 2012 at 2:53 pm

    Does this happen to other muscles as well as the heart or does plaque only build up in the coronary arteries? Can you have a bicep infarction for example?

  • Reply coolcurt4545 September 3, 2012 at 5:46 pm

    I do not work out as much, but I don't think its going to give me chest pains when I work out not that much

  • Reply hampzuz September 5, 2012 at 9:06 pm

    Heart diseases pisses me off…. Made me quit with sports and preventing me to do what i love to do.

  • Reply Dr.James Meschino September 25, 2012 at 10:22 am

    Nice video about Heart Disease. I just watch this video carefully. Thanks for sharing this video. Heart patients will be Inspired from this video and the help provided here is really great. Hope you will keep uploading more awesome videos in the future too to let us know more details on Heart Disease and Heart Attacks.

    Follow @ Meschinohealth(dot)com

  • Reply KStyIe November 13, 2012 at 7:29 am

    I love you. Your videos > 298393 pages of reading in the textbook. very clear and helpful, keep up the work for all of us fellow college and university students

  • Reply Happy30Too December 5, 2012 at 4:30 am

    Perhaps the most interesting research coming out on prevention of heart disease is the study published two weeks ago by the journal CIRCULATION of the American Heart Association. This 10 year NIH funded study found a 48% reduction of heart disease in people who were taught Transcendental Meditation. The control group used the standard education program. This finding was even more significant when looking at those who were most regular with their twice a day practice–66% in that group.

  • Reply PorknBeanJuice February 17, 2013 at 2:48 am

    I love my heart:D

  • Reply rhinovirus156 February 23, 2013 at 5:49 pm

    thank you for the insight Professor Kahn!! This definitely helps me in my pathophysiology class!

  • Reply RCT3Crashes100 March 9, 2013 at 9:31 am

    This is really helpful 😀

  • Reply Hafa Ball March 24, 2013 at 6:27 pm

    angina pectoris has to be one of the funniest deadliest disease names.

  • Reply Patrick Hayden April 20, 2013 at 4:31 pm

    Well described, thanks so much.

  • Reply Patrick Hayden April 20, 2013 at 4:37 pm

    Colour-Correlator app, for students storing & returning to info / notes, super app.

  • Reply naveen davis October 8, 2013 at 4:12 am

    for subjects video

  • Reply Jonathan Thomason October 28, 2013 at 11:47 am

    High intensity ultrasound fixes the heart. Search for ‘HIUS jonathan thomason heart’ on how to use high intensity ultrasound to clear coronary heart disease

  • Reply GamingNinja07 November 14, 2013 at 5:31 am


  • Reply Salah m March 29, 2014 at 8:04 am

    *watches video,

  • Reply Learning Simply April 29, 2014 at 1:48 am

    Hey so I know it's really hard to get noticed on youtube today but I really hope that people would give my channel a chance. I make educational videos that are similar to these. You don't even have to subscribe if you don't want to but all I ask is for you to take a look at my channel please!

  • Reply Flea Stiff May 10, 2014 at 12:31 am

    Just watched Heart Disease and Heart Attacks. Does Khan Academy have any videos on Surgical Treatment of Heart Disease and Post-Op pharmaceutical options?

  • Reply Tub Hmoob June 14, 2014 at 7:53 pm

    so cool. thanks for the lesson. 

  • Reply jenifer smith June 25, 2014 at 6:57 am

    very informative

  • Reply akaMyThought November 22, 2014 at 3:12 am

    My heart got a pain and it felt like a tearing.
    What does this mean im worried it has happend before no short of breath or anything else

  • Reply revina leo March 19, 2015 at 10:57 am

  • Reply Urcela Umram March 29, 2015 at 6:36 am

    i Cant hear it y ?????

  • Reply Harold, 4th of his name. April 15, 2015 at 4:24 am

    i like this guys voice :3c

  • Reply tsering choezom April 24, 2015 at 7:23 pm

    Learning so much from your videos. Thank you very much.

  • Reply Yonoum micheal June 5, 2015 at 3:19 am

    I 💖 this video

  • Reply RivaL November 15, 2015 at 4:34 pm

    tight angina… tight vagina 😂

  • Reply GameFactzTV January 8, 2016 at 5:26 am

    Here's something I read on the news : Tea loosens the arteries with helps fight for the prevention of atherosclerosis. This isn't like a 100% cure, but I though it was cool.

  • Reply tuti ha May 5, 2016 at 12:15 am

    I love this guy voice

  • Reply Shubhangi Manekar September 16, 2016 at 4:14 pm

    I always like to refer this because its incredible

  • Reply Bobbie__90210 December 22, 2016 at 9:15 am

    wow i had a heart attack at 37 and whatever he side is on pont

  • Reply Mallcollm Smit February 7, 2017 at 4:25 am

    But I can't stop eating fast food

  • Reply BeautyWarriors of J March 13, 2017 at 2:02 am

    Hi, please, I need your help to spread the word. Thank you in adavnce!

  • Reply Jonathan Mckeon May 9, 2017 at 9:56 pm

    Please…..The title of this video is "heart disease and heart attack", not "parts of the heart"…..You have to go straight to the point.

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    tôi biết một phương pháp để điều trị bệnh tim mạch. sản xuất tại Mỹ. chỉ có một tháng sử dụng bạn có thể cảm thấy hoàn toàn khác nhau. vui lòng liên hệ với tôi để biết và tư vấn. Ông Tú + 84973146153 (Zalo, facebook)

  • Reply mathe jou jou October 10, 2017 at 5:36 pm

    I just found out that i might have a heart desease

  • Reply Yaya Wahyu Aji setyaningsih October 13, 2017 at 9:25 am

    Nice video,

  • Reply Camila Cely November 5, 2017 at 9:33 pm

    En español por favorrrrrrrrrrrrrrrr

  • Reply Cotey Bradbury November 23, 2017 at 2:26 am

    Email me. I would like more info.

  • Reply Amanpreet Singh September 12, 2019 at 12:19 pm

    My close friends had nasty problems with her heart that often used to go crazy style and made her land in a mess. She did try some medicines but all failed. So she went on to the net and discovered Planet Ayurveda and received her Heart Care Pack that made her heartbeat in a perfect and normal way. Now she doesn't tire that easily and works for around 12 to 14 hours each day.

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