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Course: Health and medicine > Unit 3
Lesson 9: Cardiomyopathy- What is cardiomyopathy?
- Cardiomyopathy signs and symptoms
- Dilated cardiomyopathy: Pathophysiology and diagnosis
- Hypertrophic cardiomyopathy: Pathophysiology and diagnosis
- Restrictive cardiomyopathy: Pathophysiology and diagnosis
- Cardiomyopathy treatment
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Cardiomyopathy signs and symptoms
Created by Matthew McPheeters.
Video transcript
- [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.