We will take a look at the myocardium. With
the myocardium, it is the fact that we are
working with the middle part of the heart.
If it is endocardium, then you are thinking
more along the lines of valvular heart disease
perhaps. It is exactly what you are doing.
So let's take a look at the myocardium and
the categories of pathologies that come under
or affect the myocardium. We will take a look
at CHF, congestive heart failure. You know
this as being end-stage heart disease. So,
anything that causes damage to the myocardium
from dilated cardiomyopathy to hypertrophic
cardiomyopathy to restrictive cardiomyopathy
and so forth, eventually if there is enough
death that is taking place in the myocardium,
are you not going to result in CHF? The most
common cause of CHF is going to be ischemic.
So, if your patient has something like an ST
elevation in leads V1, V2, and V3, and then
you know there is a transmural myocardial
infarction affecting which coronary artery?
The left anterior descending and at some point
later on down the road, your patient may develop
congestive heart failure. You see my point.
So ischemia would be a very common cause or
actually it is the most common cause of CHF.
CHF final and common pathway of myocardial
disease. Now the way that we will approach
this is dilated cardiomyopathy and hypertrophic
cardiomyopathy would be relatively common
at least in developed countries. Is that clear?
You want to think that a dilated cardiomyopathy
as being end-stage heart disease just like
you have cirrhosis being end-stage liver
disease. Listen to what I am saying. I am
drawing a lot of parallels here and I will
keep doing this for you so that you don't
waste as much time memorizing details when
you should have been looking at the big picture
the whole time. Or honeycomb lung. You have
heard of that before, which means excessive
fibrosis and more along the lines of end-stage
lung disease. So here, dilated cardiomyopathy
including certain conditions that you would
find with restrictive cardiomyopathy and you
all know about hemochromatosis. If you don't,
you should and you will. With hemochromatosis,
you know that the heart is being encased by
iron. Think about as such. So it may result
in restrictive cardiomyopathy, but if there
is enough damage that is taking place to the
myocardium may you not result in dilated cardiomyopathy
clinically? Of course, you will. So how can
you distinguish between the two? Well, you
should see. Alcohol-induced dilated cardiomyopathy.
Alcohol is, unfortunately, a common cause
of this. Idiopathic, dilated. Hypertrophic
cardiomyopathy. We had discussed hypertrophic
obstructive cardiomyopathy with asymmetrical
hypertrophy of the intraventricular septum
resulting in obstruction of the outflow tract
between the left ventricle towards the aorta.
Did we not? And when we did, we talked about
the different maneuvers.
Restrictive cardiomyopathy, secondary to infiltrating
diseases such as number 1 hemochromatosis, such
as amyloidosis, which is then going to infiltrate
the heart and, therefore, cause restrictive
type of cardiomyopathy. Or perhaps there is
something called EMF, which is endomyocardial
fibrosis and there you go. What if you have
fibrosis of the heart? May result in restrictive
cardiomyopathy. What kind of countries and
what kind of populations might you then be
looking for when you dealing with endomyocardial
fibrosis? You are looking at intense eosinophilia
that may be occurring in your patient. Maybe
later stages of Löffler syndrome. And looking
at countries such as Africa, such as South
India the subcontinent, with lots of restrictive
cardiomyopathy and fibrosis. Endomyocardial fibrosis
not to be confused with endocardial fibroelastosis
found in young infants and we will talk about
those differences when the time is right
Restrictive. Probably one of the trickier
in terms of diagnosis because students tend
not to be familiar with or not understand
the full pathogenesis. Once again to repeat
hemochromatosis, sure it could result in restrictive.
But if there is enough damage to the myocardium
may result in dilated cardiomyopathy. Please
do not ever forget that. Specific cardiomyopathies,
ischemic, we talked about may result in dilated
cardiomyopathy, CHF, valvular induced, hypertensive.
Well, with hypertensive may result in concentric
hypertrophy of the left ventricle in which
the sarcomeres are going to duplicate in parallel,
resulting in what? Well, decreased size of
the chamber of the left ventricle thus what
kind of dysfunction? A diastolic dysfunction.
Physiologically what may then happen to your
ejection fraction early on in hypertension?
Are you able to preserve? Are there instances
in which ejection fraction is preserved with
heart failure? Sure there are. Hypertension
early on, aortic stenosis early on. It is
actually called heart failure of preserved
ejection fraction, ejection fraction being
approximately normal at 55 percent. Is that
clear? These are important points and we have
discussed this a couple of times. We will
continue to do so that we would reinforce
this constantly. We have inflammatory.
So, here your myocarditis might
be thinking about viruses such as Coxsackie.
You might be thinking about adenovirus in
myocarditis, viruses. Maybe even perhaps
part of rheumatic heart disease. "Dr. Raj, I thought that
was endocarditis and valvular heart disease
and you even told me the four valvular disease
of the rheumatic heart disease, acute type
of regurgitations and the chronic type of
stenosis. Why all of a sudden are you talking
about myocarditis?" Because rheumatic heart
diseases, pancarditis. You would have Aschoff
bodies and Aschoff cells.
Myocarditis. Infections. HIV, enterovirus, Chagas.
You sit there or actually stand up with me and
do Chagas dance. What am
I referring to? What was the Chagas?
Dilated, dilated, dilated. Three different
places obviously I am going to repeat this
in three different organ systems. But Chagas
from head-to-toe dilated esophagus.
What is this? Achalasia, acquired type. Where
am I? Taking a cruise. Where? Down the South
America and I ended acquiring trypanosoma cruzi.
You picked this up and you have Chagas and it
may result in acquired type of achalasia.
What happens to the proximal esophagus? Dilation.
Dilated esophagus. In the heart, what kind
of issue? You might have a dilated infectious
myocarditis. What else may happen? Dilation.
I said three times Chagas, Chagas, Chagas;
dilation, dilation, dilation. The third and
final dilation would be down in your intestine.
May result in acquired type of toxic megacolon.
Is that clear? Chagas is important for us.
Endocarditis. Infection, metabolic disturbances.
Well if your patient feels and tells you "Hey
doc, I feel like my heart is going to jump
out of my chest," and you find your TSH levels
being ridiculously low. What is your diagnosis?
And maybe even perhaps on a radioactive iodine
test, you find diffuse uptake of radioactive
iodine. Without a doubt your diagnosis, please?
Good. Grave's disease. We have diabetes mellitus,
of course, may result in issues in the heart.
Infiltrating. Hemochromatosis, amyloidosis
and do not forget the sarcoidosis not only
could affect your lungs resulting in non-caseating
granuloma in which there might be bilateral
hilar lymphadenopathy, which you can find
these known cases in granuloma perhaps
in the liver maybe as you see here in the
heart. Do not forget that please, ever.
Now with rheumatologic disorders, SLE sure. You
know about SLE and you might have the autoimmune
disease, in which you have malar rash, but
you could also have other types and other
manifestations could be affecting the heart.
You have polyarteritis nodosa may also affect
the heart. It is usually medium sized may be
perhaps small sized type of blood vessels might
be affecting the heart. Scleroderma you are
thinking about fibrosis immediately and
dermatomyositis in which you find skin lesions.
You have heard of Gottron lesions over the
knuckles, heliotrope and then muscle in which
finally it might affect your heart.