Understanding Ventricular Tachycardia Ablation – Risk Factors, Treatment Options, Surgery


♪ [MUSIC] ♪>>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.


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