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>> Hi.
I'm Dr. Richard Hongo and I'm a Cardiac Electrophysiologist.
Today we're here at California Pacifica Medical Center,
which is in San Francisco.
This is one of our dedicated electrophysiology labs where
we're very fortunate to have cutting edge technology that
allows us to perform complex catheter ablation procedures
such as ventricular tachycardia ablation.
Now, as you may know, cardiac electrophysiology is a sub
specialty of cardiology that deals with all different types
of heart rhythm problems.
Ventricular tachycardia is one of those problems and it is very
important primarily because it can be life threatening.
Now, there are many therapies out there for
ventricular tachycardia.
Some of them include medications that suppress the
heart rhythm problems.
Others include implantable devices such as defibrillators
which then monitor and at times need to shock patients out of
the rhythm into sinus rhythm, or normal rhythm.
Ventricular tachycardia catheter ablation is a very important
tool in the management of this rhythm problem because it allows
us to actually find the problem and eliminate the focus that is
causing the rhythm disturbance and many times really help in
controlling someone's rhythm along side things like
the medications or the implantable devices.
Today, in this video I would like to explain how catheter
ablation is used to treat ventricular tachycardia.
Let me explain by looking at the normal heart rhythm
for a minute.
When you think about the heart, the heart is essentially a pump.
It's a pump that circulates the blood through
the rest of the body.
But, if you take a closer look at the way the heart if made up
you can notice that there are multiple chambers
within the heart.
The top two chambers are the atria.
The bottom two chambers are the ventricle and the way that the
electrical activity actually organizes the contraction of
the heart is through a very complex electrical wiring system.
The activation starts in the top of the heart up here in
the sinus node, and it travels through the electrical system
from top to bottom and you can see the yellow colored
electrical system here on this diagram.
Another very important function of the electrical system,
other than synchronizing or coordinating the heart,
is making sure the heart doesn't go too fast and that's primarily
done through this top portion of the heart called the av node.
This keeps the rhythm from never going so fast that
the heart would degenerate.
Tachi means fast.
Ventricular tachycardia is essentially a fast heart rhythm
or tachycardia,that occurs from the ventricles,
the lower chambers down here.
And the reason why this rhythm is so concerning is because the
rhythm happens outside of the normal electrical wiring system
so it is no longer regulated, the rhythm can degenerate,
and it can go so fast that it can actually become
what we call a cardiac arrest.
And this, as you may know, is a life threatening condition.
The ventricular tachycardia a lot of times happens from a spot
or focus within the lower chamber that essentially
starts to act up and starts to run off on its own.
Another reason for developing ventricular tachycardia is the
electrical activity can get stuck in a loop and it goes
around in a short circuit usually involving areas that are
scarred within the ventricle.
Ventricular tachycardia ablation is all about finding the spot or
the short circuit that is causing the rhythm disturbance,
and using catheter based technology we find and
eliminate the cause.
Here at California Pacific Medical Center we have our
anesthesiologist sedate our patients very comfortably at
the onset of the procedure.
And through a small incision that I make at the groin site,
I place sheaths into the veins and you can see me putting in
catheters here.
Then we push soft insulated wires, or catheters,
through the large central veins and you can see the catheters
now floating up through the inferior vena cava.
We can also utilize the Steriotaxis remote navigation
system to move catheters inside of the heart.
There are several advantages of using this newer system.
One of them is the catheters are very soft.
You can see me pushing the catheter now up against my hand
and it buckles very easily.
This virtually eliminates the catheters causing any
unwanted injury to the heart wall.
Also in addition to this, using these large earth magnets that
are housed in these retractable towers,
and in this image you can see the towers being pulled in on
either side of the patient, the magnets then move the magnetized
catheter with millimeter precision to really all corners
of the heart just through computerized controls.
And you can see us now, dragging the arrow icon on the screen and
moving the catheter in this way.
In a very controlled environment,
we start up and stop the ventricular tachycardia
using pacing and intravenous medications and we start
visualizing where the tachycardia is actually
coming from.
Here is a reconstructed 3D virtual image of the inside of
the right ventricle in a patient with ventricular tachycardia.
The earliest electrical activation is seen here on
this map and shown by red.
So let me explain catheter ablation
in a little more detail.
If this here, my hand, is the wall of the heart,
the ablation itself is caused when the tissue underneath the
tip of the platinum catheter electrode is heated to somewhere
between 50 to 60 degrees Celsius.
Now this in and of itself is not very hot but when kept on one
spot long enough, somewhere between 30 to 60 seconds at
a time, that's enough to cause some denaturing right below the
tip of the catheter itself.
And this denatured tissue stops all electrical conduction and
over a few months time this denatured tissue then heals
itself into some permanent scare and this is what keeps
ventricular tachycardia from reoccurring.
So in summary, catheter ablation for the treatment of ventricular
tachycardia is a procedure that really relies on us being able
to precisely localize where the sight of the tachycardia is
actually coming from.
It is through real advances in technology that we've been able
to now perform this procedure not only effectively but safely.
Such as the use of 3D imaging where we're able to visualize
where that spot is actually coming from,
or the use of magnetic remote navigation where we're able to
move catheters safely as well as precisely within the ventricle.
Catheter ablation is an emerging tool in the treatment of
ventricular tachycardia and along side other therapies such
as medications or implantable cardio inverter defibrillators
it should be a treatment that is considered anytime you're
dealing with ventricular tachycardia.
I'm Dr. Richard Hongo and now you know.