- What is cardiomyopathy?
- Cardiomyopathy signs and symptoms
- Dilated cardiomyopathy: Pathophysiology and diagnosis
- Hypertrophic cardiomyopathy: Pathophysiology and diagnosis
- Restrictive cardiomyopathy: Pathophysiology and diagnosis
- Cardiomyopathy treatment
Created by Matthew McPheeters.
- [Voiceover] Alright, so let's talk about the signs and symptoms of cardiomyopathy. So, if you break down the term cardiomyopathy into "cardio", meaning heart, "myo" meaning muscle, and "pathy" meaning disease, you can remember that cardiomyopathy is a disease of the heart muscle, and we can use this knowledge to help figure out what the signs and symptoms of cardiomyopathy are going to be. So let me just draw a little diagram here to help illustrate this. Alright, so here we have a simplified diagram of the heart. And the heart is a series of two pumps that are separated by the lungs and the body. Alright, so let's give this body a few organs, maybe a brain here, and a heart, perhaps a liver, and let's maybe some intestines. Alright, so imagine this heart is inside someone's body, and you're looking at that person. So this heart's kinda mirror image. So over here on the left, this we're gonna call the right heart. And the right heart takes in blood from the body, and it pumps it to the lungs. Then over here on the right side of the diagram, we're gonna call this the left heart. And after blood is oxygenated in the lungs, it's drawn into the left heart, and then pumped out to the body. And then in the body, oxygen is exchanged, as well as nutrients and wastes, and then that blood is then sent back to the right heart, and it just keeps going in a circle like that. So, in cardiomyopathy, what happens is there's a disease of this heart muscle. And this disease causes the pump to fail. So, when this pump fails, blood is no longer adequately able to be sent out of the right heart to the lungs, or the left heart to the body. And subsequently, since it's not coming out going forward out of the pump, blood is also getting backed up. So, in the right heart, here, you have a decreased outflow, which is to the lungs. When not enough blood is getting to the lungs, you get short of breath. And so that's one of the big, one of the important signs of cardiomyopathy, and this can also be demonstrated with an increased respiratory rate. So I'm just gonna just call that "increased RR" for respiratory rate, but also here on the right heart, if blood isn't being able to be pumped outward, it's also gonna get backed up. And this backup of blood occurs in the body, because the right heart is bringing blood from the body to the lungs. And what this results in, is something known as edema. And what edema is, is it's swelling. And in cardiomyopathy or any type of heart failure, where you typically see this, is in the legs. So the legs get really swollen. Alright, so now we've kinda talked about failure of the right heart, and the signs and symptoms that that results in, but how about the left heart here? Well, if the left heart is having decreased outflow, that's gonna result in symptoms in the body, because the left heart goes to the body. And this results in a lot of classic symptoms of cardiomyopathy, one of which is that this blood that's coming out of the heart, is actually also going to the heart muscle itself, and so that heart muscle is not getting enough blood, and it responds by increasing the heart rate. And the muscle can also get really painful. And this chest pain, or heart muscle pain, is known as angina. Other things that can happen from a decreased outflow from the left heart, is that your left heart is going to... your muscles here, we'll draw in a couple of muscles, maybe, and someone with a decreased outflow from the left heart will have weakness and fatigue. And in addition, this blood isn't just going to the organs down here in the abdomen, it's also going to the brain. And when the brain doesn't get enough blood, sometimes people can faint, which is known as "syncope". But just like in the right heart, where you had a decreased outflow to the lungs, but with a subsequent backup to the body, in the left heart there's also a backup, but this time, since the blood is coming from the lungs, the backup is gonna be in the lungs here. And when you get a backup of blood in the lungs, this results in something known as "pulmonary edema". And pretty much what this means, is that there's just fluid in the lungs, and this can be heard with a stethoscope by a doctor, and it makes a sound known as "rails", or "crackles". But there are three specific types of cardiomyopathy that I want to mention briefly because they each have some characteristic signs and symptoms of their own. Now the first one is known as "dilated cardiomyopathy". And in dilated cardiomyopathy, the chambers of the heart get really big. So I'm just kinda gonna draw that in here. And what happens when the chambers of the heart get big, is that this muscle of the heart wall gets really thin, and it's not able to pump blood quite as efficiently, and so you get this failure of the heart muscle. And some of the characteristic signs for dilated cardiomyopathy, and one of them is something called an "increased jugular venous pressure". And I'm gonna just abbreviate that, JVP. Well, what does this mean? Well, over here in the right heart, the blood that's getting backed up kind of backs up in... we'll actually draw this here, 'cause we have the left heart over here, and the blood kinda backs up in some of the veins in the neck, right here we'll draw it like this, and the blood backing up you can actually see on the outside of a person who has cardiomyopathy, and these veins are very distended. And this is known as an "increased "jugular venous pressure." And another one is something known as an "S3 heart sound". So normal heart sounds have two sounds, there's lub-dub sound, and what happens in dilated cardiomyopathy is that there's blood just sitting in the chambers here. And when it flows in, that blood, instead of entering an empty chamber, like in a... or a relatively empty chamber in a normal heart, it's filling a fairly full chamber, and that makes a characteristic sound that can be heard on the chest with a stethoscope, and this sound is known as the "S-3 heart sound". And then another thing that is characteristic of dilated cardiomyopathy is an increased heart size. And this is known as cardiomegaly. So let me just erase the dilated cardiomyopathy here, and we're gonna move on to the next type of cardiomyopathy, and that is restrictive cardiomyopathy. And in restrictive cardiomyopathy, the walls, or the heart muscle, gets really stiff, and kinda scarred down. And what happens when these walls are really stiff, is that they're not able to dilate. So not enough blood is able to enter the ventricles, or these chambers down here, as what's normal, and so even though the heart muscle's still pumping, there's a decreased volume coming out of the heart, because the chambers are smaller, or can't accommodate as much fluid, so it kind of has the same effect as being smaller, and you get the same result of a decreased outflow and a backup of blood from the heart, but there's also a few other signs and symptoms that are a little more characteristic of restrictive cardiomyopathy. And one of these is actually the same as up here in dilated cardiomyopathy, this increased jugular venous pressure, which I'll again, I'll abbreviate JVP, which in restrictive cardiomyopathy, there's another abnormal characteristic heart sound, but this one is called the "S-4 heart sound". Whereas in dilated cardiomyopathy, you had this S-3 heart sound, where the blood was entering a filled chamber, that caused that sound, in restrictive cardiomyopathy, the S-4 heart sound is caused by blood entering into a chamber that isn't stretchy, it won't accommodate that blood flow, 'cause it's really stiff, and so that also makes a characteristic sound that can be heard on the chest with a stethoscope, and that's known as the "S-4 heart sound". And once again, let me just erase our diagram of restrictive cardiomyopathy, and we'll move on to the last type of cardiomyopathy, and that is hypertrophic cardiomyopathy. Alright, so in hypertrophic cardiomyopathy, you get a little bit of the same kind of effect as in restrictive cardiomyopathy, where the walls aren't as stretchy, but in hypertrophic the walls get really big. And that's kind of demonstrated by the name, hypertropic, and when a cell becomes hypertrophied, it means it gets bigger. So that's how you can remember what hypertrophic cardiomyopathy is. So let's make these heart muscle walls a lot bigger. But one thing that's very characteristic of hypertrophic cardiomyopathy, is that this expansion, or kind of widening of this septum that goes between the two ventricles here, it gets asymmetrically enlarged, right here, and what happens is that this hypertrophied septum blocks the outflow of blood from the left heart here, from the left ventricle, further really exacerbating these symptoms of cardiomyopathy in the left heart, and so when this happens, similar to in restrictive cardiomyopathy, because you have this non-stretchy heart wall, you also get that S-4 heart sound. But in addition, you get a very characteristic murmur. And what a murmur is, is it is a sound that happens in the heart from turbulent blood flow. And the murmur that's very specific to hypertrophic cardiomyopathy is known as a "systolic ejection murmur" that increases with the Valsalva maneuver. But what does this all mean? So, let's kinda break this down. Well there's two phases to a heart pumping: it has the filling phase, when the heart muscle is relaxed, and that's known as diastole, and it also has the ejection phase, when the heart muscle contracts, and that's known as systole. So this murmur occurs during systole, when blood is being ejected out of the left ventricle here, and it's caused by turbulent blood flow. The blood doesn't pass through there smoothly, and that causes a characteristic sound that you can hear with a stethoscope. And you can imagine that if this space between the septum and the aorta coming out of here, or this wall over here, were to get narrower, that turbulent flow would become worse. And Valsalva is just a name for bearing down, like you're gonna have a bowel movement. And what happens when you do a Valsalva maneuver, is that less blood comes back to the heart, and that makes this chamber, the left ventricle, smaller, and when the chamber of the left ventricle's smaller, this wall over here becomes closer to this large septum, and so when blood is now being ejected across that narrowed opening, the murmur becomes more intense, and it becomes louder with a stethoscope. So that's why you have a systolic, ejection murmur that increases with Valsalva. And this is very, very characteristic of hypertrophic cardiomyopathy. In fact, it's so characteristic of this disease, that any child or anyone that has this type of murmur, actually should be worked up for hypertrophic cardiomyopathy, even if they don't have any of these symptoms over here. Alright, so this was just a brief overview of the signs and symptoms of cardiomyopathy, which is a disease of heart muscle. And you can remember that if your heart muscle is diseased, and you're not able to pump blood effectively out of the right and left hearts, that you're gonna have certain symptoms in the lungs and body, as well as blood is gonna back up into the body from the right heart, and back up into the lungs from the left heart. So you have these nonspecific symptoms that are characteristic of all the different types of cardiomyopathy, but there's a few other signs and symptoms that are a little more specific to each of the different types of cardiomyopathy, and those are listed here.