The 9 CYANOTIC (5 Ts + 4 more) cardiac diseases !!!!

Hello, I am Dr. Tala. Welcome to Tala Talks NICU, where we break down medical concepts and make them really easy for you to understand. Today, we are continuing our talk on congenital heart diseases. So if you haven't seen, well, honestly, you probably don't have to see part one. This one kind of stands alone. So see it if you're interested. So today's video, I'm just gonna go over kind of the cyanotic congenital heart diseases and just talk briefly about all the different critical heart diseases before we start devoting videos to each one separately. Before I continue, please remember to like this video and to subscribe and to write to us and let us know what you'd like to see next. We love hearing from you so much. Right, so let's talk about critical congenital heart diseases. So heart diseases occur in about 1% of all babies, which is, if you think about it, a really high number. Or really, it's kind of eight to nine out of 1,000 babies, which is nearly 1%, a really high number. The critical congenital heart diseases account for about 25% or a quarter of the total congenital heart diseases. A heart disease is considered critical if a baby needs surgery within the first year of life. Critical heart diseases are the leading cause of death amongst all congenital malformations. So as you all know, really bad heart diseases can have a really bad prognosis. Really weird things can happen during heart development. As you all know, the heart is made up of four chambers with vessels that feed into the heart and vessels that leave the heart. And during development, just about anything can go wrong with the different vessels, the placement of the vessels, the size of the chambers, even the valves between all the vessels and the chambers. Then the different positioning of all these vessels and chambers can then affect the way that the blood is either pumped to the body or the way the blood is pumped to the lungs after the baby is born. So if there isn't enough blood going to either the body or to the lungs after the baby is born, then the baby, by definition, has a critical congenital heart defect. When the baby does have a critical congenital heart defect, the baby will often appear cyanotic. So now you can go back and look at the first video because I talked a lot about cyanosis there. There are five classic cyanotic congenital heart diseases that we talk about. There's actually a few more, but they don't begin with T so we don't talk about them as much. But the five T's are as follows. So one, truncus arteriosus, where basically the pulmonary artery and the aorta are kind of one big trunk leaving the heart. Two, transposition of the great artery or great vessels it's called, where basically the pulmonary artery is coming out of the left ventricle and the aorta is coming out of the right ventricle. And so obviously you need some mixing to make sure that blood is kind of going to where it needs to go. Three, tricuspid atresia, where the tricuspid is just not made. So the blood is forced out of the right side of the heart into the left side. Four, tetralogy of Fallot, where basically you don't have enough blood going to the lungs from the right side of the heart. So the left side kind of becomes more important in getting the blood over there. And five, total anomalous pulmonary venous return, which is also called TAPVR or total anomalous pulmonary venous connection, TAPVC. And that is where the pulmonary veins that should be draining into the left atrium are actually draining into the right atrium. So again, you need a way for like blood to get over to the other side as well. So those are the five T's. Somebody came up with a very easy way to remember all of these. And they're all kind of connected to the numbers one through five. So truncus is one because it's only one vessel like the aorta and the pulmonary artery are kind of combined coming out of the ventricle. So truncus, TGA, where the aorta and the pulmonary artery are switched. And so those two vessels are switched. So TGA is two. Three, tricuspid atresia, because the valve is supposed to have like three leaflets, the tricuspid valve. And so you remember it that way, tricuspid atresia. Four, tetralogy of Fallot, which is number four because tetralogy means four, but tetralogy of Fallot has four features that we'll talk about later. And five, and this is probably the weakest, TAPVR because it's got five letters. Then there are four other congenital heart diseases which are mostly cyanotic that you should know about, but they don't begin with T. The first one is Epstein's anomaly, which we talked about in the last video. It's where the babies have the huge heart. And really that's kind of where the whole right side becomes kind of one huge atrium, right-sided atrium. The second is a hyperplastic left heart where the left ventricle is just not formed normally. And really the whole right side is responsible for getting blood to the systemic circulation. These are bad. The third one is a double outlet right ventricle where basically the aorta as well as the pulmonary artery are kind of coming out of the right ventricle. This is kind of an extreme version of a tetralogy of Fallot. And then the fourth one is a pulmonary atresia where you basically don't have any blood coming out of the right ventricle. And obviously these babies are gonna appear very blue. I tried really hard to come up with a better mnemonic with the five T's, but the best I came up with was five T's and FED, P-H-E-D, which is not great. I'm not gonna lie. The two most common cyanotic congenital heart diseases are the tetralogy of Fallot as well as the TGA. There is another mnemonic that I think I do find helpful sometimes. And so I want to go over that with you. And that is which of the five T's result in increased or decreased blood flow to the lungs. And this is really helpful when you get a chest X-ray, when you're trying to figure out what's going on. And I talked about this in the last lecture as well. If the lungs look really black, you can kind of assume that there's decreased blood flow to the lungs. If they look like there's like loads of white vasculature everywhere, then you assume that there's increased blood flow going to the lungs. So I'm gonna go over this mnemonic now. Right, this is how you remember which ones have increased blood flow to the lungs. I love you in sign language. This means I love you in sign language. And this really is true. Somebody did tell me this once. So the ones with increased blood flow are one, two, and five. So remember the five T's, that would be increased blood flow to the lungs, truncus, TGA, and TAPVR. So really most of the time, the tricuspid atresia and the TET would have way decreased blood flow to the lungs. So I love you. There are also three other pretty important points I want to make. The first one is about how the heart forms. As you all know, the heart is fully formed by the end of the first trimester. And then after that, it's just kind of growing and developing more. So what you need to understand is that if there is something made abnormally in the heart in the first trimester, so let's just say the left ventricle is kind of way smaller than it should be, something abnormal happens by bad luck during development, and the left ventricle is much smaller than it should be, two big things will happen. The first one is the way the heart is made is dependent on blood flow to that area. So if the left ventricle is really small, then there's a really good chance that the aorta is also going to be really small because it just didn't get the blood flow to develop normally. So that's one thing. The other thing is, is the heart is pretty smart or whatever the word is, that if the blood can't get out that way, then there'll be some sort of alternation that will happen to make sure that blood can still get out. So maybe that baby will end up with a much larger VSD, which in utero at least, will allow that blood to get to the rest of the body. The second point is, is that a lot of these heart diseases are completely fine when the baby is still inside the mother. The baby could continue growing normally and have no issues while the placenta is basically supporting the baby. And the reason for that is that in utero life, the heart is not really responsible for sending the blood to the lungs. Because if you think about it, the blood is being completely oxygenated by the placenta. In fact, in utero, most of the blood that comes back to the right side of the heart is being shunted over to the left side of the body or the left heart through the PFO and the PDA and away from the lungs because they're trying to get that blood going to the placenta to oxygenate it. So in utero, the heart is kind of only doing half its job. It really has to send blood to the systemic circulation. Then after the baby is born, the heart needs to be able to send blood to the body as well as blood to the lungs, which is very often the reason why immediately after birth or soon after when the ductus or whatever closes, that's when the baby starts getting into difficulties. That it can't then continue to send blood to the lungs as well as to the heart because it was made abnormally. There are a few times when a baby with a heart disease does get really sick in utero. And normally the way that presents is with hydrops. So really what's ending up happening here is that the heart starts failing. So it's trying really hard to still send the blood that it needs to the body, but it's still failing with that. And it starts failing. And so you end up with kind of build up of venous congestion and the baby ends up edematous. And go back and watch the hydrops video if you want to understand that better. So hydrops is a really bad prognostic sign in a baby with cardiac disease because if it's reached that point, then the heart is obviously incredibly sick. And the third thing I want to say, which I don't think I really understood until I left fellowship, is that these are all beautiful classifications, the TGA and the TET and the Epstein's. But in reality, once you actually start doing the full diagnostic workup and you're getting the echoes and maybe the 3D MRIs or CT scans or whatever, really a lot of these heart diseases are kind of a mixture of two of them. Or even if they are just a pure TET, there could also be a right-sided aortic arch or coronary abnormalities, or loads of other things that could be going on with the heart. So in reality, they don't generally fit into the perfect classification system, five Ts that we've given. And the last thing I'll say is that even though this diagnosis can be absolutely devastating for parents, the prognosis of these infants is improving drastically over time. So even a hyperplastic left heart, when I was in residency, we had long conversations about whether we should encourage comfort care for these babies. Every year, the outcomes seem to be improving on these babies. And a lot of these babies born with critical congenital heart diseases are going on to lead very happy, healthy lives with an excellent quality of life with really nothing to show of the ordeal they went through apart from the scar that they have. And that's it in the introductory part of the congenital heart diseases. From now on, I'm gonna go through kind of every lesion separately. I hope that you learned something today. Please remember to like this video and to subscribe. And I just want to thank you again so much for being here.