Alicia: One of the things that is so important for us as coders is to know the anatomy and
the physiology of what's going on with the different body systems.
Q: The conduction system of the heart can lead to coronary artery disease, cardiomyopathy
and valve disease.
A: So I work up this great quick study for you, I told Laureen I was going to be talking
a lot tonight.
Laureen: Yay!
Alicia: Might have to make it bigger or I won't be able to see it [laughs].
The conduction of the heart, the first thing you need to know is the anatomy. When you're
looking at the heart, see these red lines , those are the electrical system, you could
say, of the heart or what powers the heart. We have the SA node, which is the sinoatrial
node. They're at the top and you've got those three -- think of them like little rivers
of electricity that ran down. And then you've got the AV node or the atrioventricular node
and these nodes snapping from one to the other is what makes the heart pump because it sends
an electrical current down that line that forks and goes to the bottom of the heart
around the ventricles.
If you didn't know, you've got the right atrium at the top, the right ventricle at the bottom,
left atrium at the top and the left ventricle at the bottom. So, the ventricle is what squeezes
because the electrical current tells it to and whoosh! All that blood goes up through
the heart. OK?
Go ahead and slide down just a little bit. There is a description kind of how that works.
You first going to get the electrical current in the SA node and then it's going to shoot
over to the AV node, and it does it in about 60 to 100 times a minute. So if you can think
of that little zap, zap, zap, that fast. Amazing how that works. This is known as the "natural
pacemaker" for the heart. And when you're having problems with your heart or the electrical
portion of your heart, that's why people get pacemakers, in fact.
The SA node sends the electrical impulses at a certain rate. Think of it going zit,
zit, zit, zit -- I can't even do it that fast, you know. But your heart rate may still change
depending on the physical demands. So let's say that you're out for your morning jog,
of course your heart rate is going to go up. You have a scare your heart rate is going
to go up. Hormonal factors actually will make the heart rate change, but the heart is still
working the electric current at the same pace. And that signal from the brain to the heart
can get a little messed up once in a while. If we scroll down just a little bit more,
this is not as big of a picture but we're going to put in a very important part of this
system now, it's called the Bundle of His. That's right there in this picture like an
inch before you get that fork between the ventricles. That Bundle of His is extremely
important as we'll see, as we'll scroll just a little bit more.
For the left and right ventricles to contract at the same time, that electrical pulse has to travel
down the right and left bundle branches -- that we saw, that little fork, at the same speed.
If there is a block in one of these branches, the electrical impulse must travel to the
ventricle at a different route -- which is going to mess everything up.
When this happens, the rate and rhythm of your heartbeat is not affected, but the impulse
is slowed. So, your heart is pumping at the same rate
but that little electrical current is slowing down and that is going to cause some problems.
Your ventricle will still contract, but it will take longer because of the slowed impulse.
This slowed impulse causes one ventricle to contract a fraction of a second slower than
the other. And you see both of those ventricles have to work at the same time at the same
speed to work properly. So, if one is going a little bit slower than the other, it actually
can cause a big problem.
The block can be caused by coronary artery disease, cardiomyopathy, or valve disease.
Right bundle branch blocks may also occur in a healthy heart -- so you can still have
these problems, if you're an athlete and your heart is in good condition. This is not about
the muscle of the heart, this is about the electricity or the electrical current that's
running through the heart. This is all based on nerves.
Doctors can use an EKG or an ECG machine to record the electrical impulses of your heart.
And a bundle branch block shows up on the EKG tracing.
Regarding the cardiology, the electrical conductivity of the heart, the main terms that you want
to know are going to be: the chambers of the heart, you're going to want to know the SA
and the VA node and you're going to want to know the Bundle of His. For the physiology,
you want to know that those little left and right (I'm calling "rivers" there) have to
go at the same time -- the electrical current/pulse at the same time at the same speed, or there
will be things like atrial flutters and stuff.
It's very fascinating; this is just a window into it. There are people that do this exclusively,
study this. Amazing, a lot of information out there and also the website is cited there
where I got a lot of this information. Again, this is just a touch.
Laureen: Yeah. The Texas Heart Institute, they got a lot of good stuff on their site.
Alicia: Amazing stuff down there.