Plaque-> stenosis-> ischemia-> heart failure-> myocardial infarction/heart attack-> cardiac arrest
What is heart failure?
Great explanation of stenosis and how it can lead on to ischemia causing a lack of blood supply to further muscles in an individuals cardiovascular system. Short revision on heart failure, thrombo-embolisms, coronary artery disease and coronary heart disease.
stenosis is the narrowing of a blood vessels and arteries ischemia is restricted blood supply . when you get both of these your heart muscle gets less oxygen to it this leads to heart failure this is called coronary artery disease , coronary heart disease or heart disease . infarct or infarction is dead tissue that hasn't had any oxygen to it this is a heart attack
As someone who's married to a doctor. In the medical field, it's pretty important to have a precise
understanding of what the words mean, just so you can understand what people
are talking about. If either you are a health care professional, or if one is talking to you
as my wife does... well, sometimes does, when she comes home from work.
So let's get a little more precise with the words we've been talking about, especially with
heart disease and heart failure and all of the rest. So let's say this is an artery
and the blood is flowing in that direction... and let's say this right here is an artery.
Now, let me draw a plaque there. and we've been studying plaque since the video on heart attacks.
So let's say this is a clump of white blood cells and lipid materials and all the rest
Now, a word that you might hear in a medical context is "stenosis", and the word
just refers to the narrowing, usually of a blood vessel. So, this right here, this blood vessel has been narrowed.
It can also refer to the narrowing of any type of tubular structure, so if you have
any type of pipe in a biological system, you can use stenosis there, but usually they're
talking about a blood vessel. In this example here, it's an artery.
Now, once the blood vessel is narrowed, that restricts the blood supply
so you aren't able to get as much blood through it, so the blood supply
is restricted. This restriction of blood supply that usually leads to some loss of function
is called 'ischemia', another fancy word, that literally just means 'restricted blood supply'.
Now if you have stenosis in one of your blood vessels, and it leads to ischemia
then the muscles, and let's just say this a coronary artery here...
the muscle cells over here are going to get less oxygen.
So this muscle cell over here is not going to get enough oxygen -- and this is an oversimplified diagram
And, this is not what an actual muscle cell looks like. But I don't want to get into detail here...
But, this guy is not going to get enough oxygen. So, you can imagine that if we're really zoomed in on the surface of the heart
and we're looking at the cardiac muscle tissue, if this person with this heart needed to go jogging
and this cardiac muscle cell needed oxygen, they probably wouldn't be able to get the needed oxygen
because of the stenosis which caused ischemia.
And because of that, this cell won't be able to help the heart pump properly
So this is going to lead to heart failure, and once again the word heart failure
sounds more dramatic than it really is. It sounds like the heart stops (cardiac arrest)
but it's really just saying that the heart is failing to PROPERLY do it's function -- not entirely shutting down.
So when this guy is jogging, because he has restricted blood supply
because the heart is experiencing ischemia downstream from
this stenosis, that's why there's heart failure -- so not able to deliver
Now, this heart failure which is due to the ischemia and the stenosis
you would call this heart failure due to 'Coronary Artery Disease'
which is really just kind of an impairing of the heart's function
because of reduced blood supply, because of narrowing of the blood vessels
that is Coronary Artery Disease, and because of this disease
when this muscle cell in the heart really needs to pump hard
maybe because someone's going up a hill or climbing stairs
it won't be able to do it because it's not getting enough oxygen.
Now, that inability to properly pump -- not just the cell, but the whole heart -- that is heart failure.
Now you've probably the heard the term 'Coronary Heart Disease'
or maybe just 'Heart Disease'... these three things are all the SAME thing.
They all imply some sort of narrowing, or stenosis, of arteries that leads
to ischemia, reduced blood flow, so that the heart can't function
as well as it otherwise could. Now the last thing I want to focus on
and I talked a little bit in the last video, is the idea of an infarct or infarction.
These are kind of... funny words to say, so I'll right it over here
So, an infarct or infarction... now, in the example I've drawn so far
this cell maybe doesn't get enough oxygen, especially when the person is going up stairs and all of that,
to properly contract the heart and pump blood. But this cell is not dead.
It's still getting some base level oxygen -- less because of the stenosis and ischemia
but it still gets some oxygen. Now we saw on the video on myocardial infarctions
or heart attacks that sometimes, one of these plaques might become
unstable and they break off and then you have a complete blocking
of a vessel, and we called this -- if it's an embolus...
and remember that an embolus is something that is just floating around
and eventually blocks a vessel, and if it was a due to a ruptured
plaque that also had clotting factors around it when it was released,
then we would call this a thromboembolism.
And this would reduce the blood flow so much, that the cells downstream
from this location actually die
because it's not even getting enough blood, not enough oxygen, to survive
and when you have dead tissue that's due to a loss of oxygen, this is an infarct.
The process of it becoming dead tissue due to a loss of oxygen
is an infarction. When this infarction occurs in the muscle tissue of the heart, this is a heart attack
This is a myocardial infarction... so hopefully that clarifies things a little bit.
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