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PULMONARY VEIN ABLATION (ISOLATION)
Current Pulmonary Vein
Ablation techniques are achieving success rates of 70%-85% in curing Paroxysmal
A-Fib with low risk.17,33,34,41
(Check with your particular heart center for its success rate.) "Curing"
A-Fib is defined as restoring patients to normal sinus rhythm without dependence
on any medications.41
(The other 15%, though not "cured" of A-Fib, may be significantly improved after
an ablation. They may have fewer or less intense attacks of A-Fib. Medications
that didn't work before may now control the A-Fib. But for some there may not be
any noticeable improvement at all.)
Pulmonary Vein Ablation
(Isolation) is currently the best technique available for
curing A-Fib.18,19,20
During Pulmonary Vein Ablation a soft, thin, flexible
tube
with an electrode at the tip is inserted through a large vein or artery in your
groin and moved into your heart. This catheter is directed to
the precise location(s) in your heart that are producing your A-Fib. These
points are burned off or isolated from your heart. This is a relatively
new procedure. (The first journal published report of a successful catheter ablation
for A-Fib in humans was done in 1994 in Bordeaux,
France. 21
The first published studies of Focal Ablation (Pulmonary Vein Ablation) within the Pulmonary Veins came
from Bordeaux47
and Taipei.48)
Currently,
many
heart centers in the U.S. are doing Pulmonary Vein Ablation
(Isolation) of A-Fib on a regular basis. (For a partial
list of these facilities, see Facilities.)
This is a relatively painless procedure, because there are no
nerve endings in the smooth tissue of the heart and veins. However, someone
recently wrote me that they felt a lot of pain from the ablation burns.
If you are in A-Fib during the
Catheter Ablation procedure, it's relatively easy for the doctors to determine
where the A-Fib signals are coming from and to ablate (remove) them. However, if
you have intermittent A-Fib (Paroxysmal A-Fib),
it's harder to pinpoint exactly the source(s) of the A-Fib signals.
The challenge for doctors is how
to locate and
eliminate A-Fib signals when the patient
is not in A-Fib.
Since research
has shown that most A-Fib signals come from the
openings (ostia) of the four Pulmonary Veins in the left atrium, one technique
is to make Circular Radiofrequency (RF)
Ablation lines around each pulmonary vein opening (called "Circumferential"
or "Empirical Ablation"). This isolates the pulmonary veins from the rest of
the heart and prevents any pulses from these veins from getting into the heart.
However, it's difficult to make circular RF lesions and they aren't always
successful. (A new experimental technique of circular ablation uses a balloon
catheter and ultrasound, laser, or cryo (freezing) energy to encircle the vein opening and make the
circular lesions.22)
A different method of
locating and eliminating A-Fib signals (called
"Segmental Catheter Ablation") uses Pulmonary Vein Potentials. A
potential is
an electrical charge or energy---like the battery energy in your car. Even if
your car isn't running, you can still measure 12 volts "potential" at the
battery. Similarly, in your heart any potential in a pulmonary vein area can be
measured and pinpointed, even if you aren't in A-Fib at the time. When the area
is ablated, the potential disappears. Like taking the battery out of your car,
removing this potential eliminates your A-Fib. As mentioned above, this
technique can achieve success rates as high as 85% with low risk for people with Paroxysmal
A-Fib.17,34,41
For people with Chronic A-Fib, success rates may not be as good. (See
Chronic A-Fib.)
Instead of ablating inside the Pulmonary Vein Openings which
may risk Stenosis, the pathways taken by these A-Fib signals from the Pulmonary
Veins are located and ablated outside of the Pulmonary Vein openings. The A-Fib
Pulmonary Vein potentials or sources of A-Fib signals are disconnected from the
rest of the heart.
Another procedure for isolating A-Fib signals is called
"Anatomically Based Circumferential Pulmonary Vein Ablation" by Dr. Carlo
Pappone of Milan, Italy who first developed this technique58.
It is also called "Left Atrial Ablation" by Dr. Fred Morady of the Un. of
Michigan60.
Instead of concentrating on the Pulmonary Veins and Pulmonary Vein Potentials,
the emphasis is on creating blocking lesions in the left atrium similar to
"Circumferential" ablation described above. But instead of trying to make
continuous, perfect linear lesions, a large diameter catheter at a high wattage
is dropped and dragged to make the circular linear lesions. There may be gaps
left in these lesions which may result in Atrial Flutter. But over time scar
tissue usually closes these gaps (see
Morady and
Pappone). (At
the 2008 Boston A-Fib Symposium Dr. Pappone's presentation showed nearly
continuous, perfect linear lesions with very few gaps.)
Pulmonary Vein Ablation (Isolation) is a low
risk procedure33,
but it is not risk free. For a more in depth look at the actual risks involved,
see Risks in the FAQs section.
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