well welcome to another MedCram lecture we're going to talk about heart
failure today now sometimes this can be a little confusing because there's a lot
of different definitions this was known as congestive heart failure and there's
been some new definitions that have been introduced that have been a little bit
confusing as well and we're going to go over the basics first here in the first
lecture and tell you a little bit about the definitions and also the path of
physiology behind heart failure now generally speaking if you look at the
heart and we will symbolize that here with actual heart remember the heart is
just a pump and you've got blood going into it and by definition all blood that
goes to the heart must go to the heart via veins and then you have blood coming
out of the heart and by definition those are arteries now of course in the
pulmonic circulation the arteries have deoxygenated blood and the vein has
oxygenated blood and in the systemic circulation all of the arteries have
oxygenated blood and all of the veins have deoxygenated blood and we'll talk
about that a little bit later but as you can see the heart is meant to pump blood
and have it flowing in the correct direction generally speaking if you have
heart failure you're not going to get as much blood going forward and you're not
going to get as much blood going in and so as a result the two major types of
symptoms that you're going to see in heart failure is not enough forward flow
and because there's not enough forward flow blood stays in the heart and as a
result of that blood which should be entering the heart is not entering the
heart and as a result of that you're going to see congestion before it okay
this is like an accident on the freeway there is no traffic in front of the
accident because there's not enough forward flow but we certainly know
there's plenty of traffic before the accident and there is quite a bit of
congestion now things would be pretty simple in this situation if this is all
that we had and so we're gonna get into a little bit more detail but let's look
at how these symptoms manifest themselves not enough forward flow could
mean number one kidney function decreases just think about all of the
organs which are all of them that rely on blood perfusion and if the kidneys
are not getting enough blood you're going to have kidney function decreasing
that of course is going to activate the reno angiotensin system or the Rass
system it will also activate the anti diuretic hormone system of course this
is going to increase the amount of fluid retention that you have and that could
exacerbate your congestive heart failure number two think about your pulmonary
system and think of chain Stokes respirations okay so not enough carbon
dioxide is circulating and therefore you get chained Stokes ventilation where you
breathe fast and then you breathe slow a lot of the symptoms that you see are on
the congestion side and so certainly when you have congestion the first organ
that it goes to is the lung so think of pulmonary edema but if it keeps backing
up you know that the next organ it's going to go to is the liver so liver
congestion so you could see the ast and alt go up this is also known as nut Meg
liver because if you do a cross-sectional of the liver it would
look like there is nutmeg you would also get elevated pulmonary artery pressures
and also think of pedal edema
so these constellation of symptoms can be divided in problems associated with
poor output and problems associated with poor input or congestion and in any
heart failure you could see both of these types of symptoms now I want to
talk about the heart itself now the heart we set as a pump but it's not your
typical swimming pool pump which you just turn on and just runs continuously
it actually has two very distinct actions it has an action of active
contraction and it also has an action of active relaxation and it's this active
relaxation that is the most misunderstood and so there are two
phases of this pump if you will a two stroke pump where there is one phase
called systole and there is another phase called diastole now systole is
where there is active contraction
diastole is when there is active relaxation if you have a problem with
either of these two functions you could get congestive heart failure systole is
when the heart is pumping blood actively into the aorta and to the systemic
circulation and pulmonic circulation when it relaxes however blood enters
from the veins into the heart both the pulmonic vein and also the inferior vena
cava and allows the heart to fill if the heart can't contract you have something
called systolic dysfunction if the heart can't relax you have something called
diastolic dysfunction there is something that is known as the ejection fraction
otherwise known as the e F the ejection action is simply the size of the heart
@n diastole in other words the size of the heart when it's the largest - the
size of the heart at and systole in other words the size of the heart after
it contracts so in other words what we're looking at here is how much blood
was pumped out of the heart and we divide it by the size of the heart at
the end of diastole so what we're saying here is that the ejection fraction is
the proportion of blood that the heart can pump out in one contraction the
thing I want you to notice is that if the heart has a hard time contracting
this number up here is going to get smaller but this number is going to stay
the same let's review that again if there's a problem with systole if the
heart is too weak to contract then these numbers are going to be very similar and
therefore the difference between them is going to be very low this number will
not change however and so the ejection fraction will go
down in systolic dysfunction however in diastolic dysfunction
remember what the problem is the problem is is that the heart can't relax and as
a result of the heart not being able to relax this number will go down and as a
result when you have a small heart that can't relax there's not a lot of blood
that you can pump out of a small heart and so therefore what happens in this
situation is this will stay about the same or if it goes down this also goes
down and so as a result the ejection fraction and diastolic
dysfunction is about the same it doesn't change and this distinction
has been made with the new classification let's talk about that
officially speaking this is the new terminology there's something called
heart failure due to reduced ejection fraction and then there is heart failure
with normal ejection fraction now if you notice here is the reduced here is the
normal that's all you really need to look at you know that if you have a
reduced ejection fraction then you have systolic dysfunction
and the problem here is that blood cannot be ejected out of the heart blood
can't get out as a result of the fact that blood can't get out then
blood can't get in to the heart okay now with a normal ejection fraction what's
the problem here the problem is is that blood can't get into the hearts because
the muscles won't relax when the muscles don't relax they can't
relax enough to allow the blood to come into the heart during diastole and so
here the problem is is the blood can't get in and as a result of the fact that
the blood can't get into the heart the blood can't come out of the heart the
heart can't pump that blood out if it's not getting in blood can't get out
notice you have the same problems in both types of heart failure but the key
is is the why the reason why you have heart failure due to a normal ejection
fraction is because blood can't get in the reason why you have heart failure in
a reduced ejection fraction is because blood can't get out now what are some of
the causes of these things let's talk about reduced ejection fraction so
things that can cause reduced ejection fraction would be ischemic heart disease
so you haven't had enough oxygen going to the heart and as a result of that
tissue has died and it's no longer functional it's weak if parts of the
whole muscle die you can even have aneurysms of the heart muscle so ask
emic heart disease is classic think of this in coronary artery disease people
that have had cabbage people with diabetes okay so what's the problem in
normal each action fraction well remember here is that blood
and get into the heart and the reason why blood can't get into the heart is
because they've had hypertension for so long that their muscles are so thick
that they can't relax anymore so the big one here is hypertension almost
certainly so think of these in patients with a normal ejection fraction and
they've got thickened myocardium left ventricular hypertrophy these people
still benefit from lasix because remember blood can't get in
there for blood can't get out and if blood can't get in it's going to congest
into the pulmonary circulation so the key that I want you to remember here is
if you suspect somebody has congestive heart failure and you get an
echocardiogram and the ejection fraction is greater than 40 percent you really
can't say that this patient doesn't have congestive heart failure because they
very well certainly can they would have heart failure with a normal ejection
fraction we'll talk later about some of the other aspects of heart failure
please join us for our next video thanks for joining us
you