00:00
Let's talk about what happens
when someone survives
a heart attack,
things have gone fairly well
and what happens
after dead tissue.
00:08
Because we know that
we have dead tissue
because blood supply
was cut off to an area
for about 20 minutes at
least after four hours
those cells or the
cardiomyocytes die off.
00:20
I know this is a little
bit of the sad part.
00:22
It's kind of like
watching Bambi.
00:23
We have to fast-forward
through the mom's death
to get to the good
part at the end.
00:28
So let's get this
part out of the way.
00:30
The tissue is dead
after 4 hours.
00:33
It cannot be revived.
00:35
So the cells or the
cardiomyocytes die.
00:38
So in this example,
it's been longer than four hours
and those cells have died off.
00:43
So the cardiomyocytes are dead.
00:48
I just had a moment
of silence for them.
00:49
We want to recognize
that and keep moving.
00:51
All right,
so the cardiac myocytes
they fought a good fight,
but after four hours,
they are irreversibly dead.
00:59
So let's talk about the
wave of first responders.
01:02
There's a first wave,
a second wave and a third wave.
01:06
Now the first wave is
the first 12 to 24 hours.
01:10
What happens in your body
these myocytes are dead.
01:13
Then the first 12 to 24 hours
neutrophils will respond.
01:17
They will rush into
the dead heart muscle
and they'll begin
the first waves
of breaking down the tissue
that's part of the process
of rebuilding the wall.
01:25
You've got to get the
rubble out of the way.
01:28
So first wave neutrophils
so circle the word neutrophils
just as a quick reminder to you.
01:34
The second way starts
one to three days now
and even larger team of
neutrophils arrives in (tada).
01:41
It's gonna help
lice the dead cells.
01:44
Remember those cardiomyocytes.
01:46
First wave,
neutorphil's are the first team
that arrives over 1 to 3 days
even more neutrophils will
arrive to help do the work.
01:54
In the third wave It's the
macrophages that arrive
they are the movers
and the shakers.
02:00
They're going to start
removing all the debris
including the neutrophils
that are flat tuckered out
from the first and second wave
and there you do this
through phagocytosis.
02:10
So first wave 12 to 24 hours
team and neutrophils
arrives to the dead tissue
and one two, three days
even more and even larger
team of neutrophils arrived
so underline that again,
but the third phase is the
movers and the shakers, right?
You've got the macrophages.
02:27
They are going to start
getting rid of the debris
including those guys that are just
flat out too tired to keep going
and they're going to do
this through phagocytosis,
which is what macrophages do.
02:39
Now this are signs of new
life granulation tissue
is kind of like springtime
been through the winter
and the dark and the dead.
02:46
Now we're kind of
getting ting to spring
It's the sign of new life
in that wall of your heart.
02:51
After about 7 to 10 days,
these really thin blood vessels
will start to grow and they
can provide some oxygen
but it's going to take a week
to 10 days for these guys
to just start growing,
now they're pretty fragile
and they're really thin
but that's what happens in
the first week to 10 days.
03:11
After that,
We get some fibroblast
and they start making
some structural protein strands
called type ll collagens
so we've got these
very thin blood vessels
they're going to start to grow
and they can give
you some oxygen
which that's really
good for the wall.
03:28
Then we get these fibroblasts
and they're going to make these
structural protein strands
and we call them what?
Right, type ll collagen.
03:36
That's going to be
a little stronger.
03:38
Now these together
these tiny blood vessels
and these fibroblasts that
made this type to collagen.
03:44
They start making
granulation tissue.
03:47
That's a really positive sign.
03:50
Now later on, the granulation
tissue is going to be replaced
with much stronger
type l collagen
that's called scar tissue.
03:58
Scar tissueis going to be tough,
but it's not going
to be as flexible
and as workable as the
tissue was before and here's
even more about the problem
because scar tissue
isn't as effective
as the original cardiomyocytes.
04:14
Okay, that's a really
important point.
04:15
So I want to make sure I don't just
speak through that too quickly.
04:19
Scar tissue is not as effective
as original cardiomyocytes.
04:24
It's better than dead tissue,
but it's not like the
original equipment
because scar tissue
isn't as quite as strong
as the original muscle.
04:32
It's also not contractile.
04:35
So depending on
how big the hit was
and where it was
the heart just isn't going
to flat pump as efficiently.
04:41
Remember that initial
animation that we looked at
how everything was smooth
and work together and
everything was equal.
04:49
Well,
once you've got scar tissue,
it's not going to be quite as
strong as the original muscle
and it's not going to
be as contractile.
04:56
So it doesn't pump
as efficiently because
it's kind of stiff.
04:59
It also could increase the
risk of the patient developing
heart failure later
because if it's a big enough
hit or as things progressed,
remember the heart
is not as efficient
and it might not be able to
handle the patient's fluid volume.