Atrial fibrillation is a
very common, rapid,
and disorganized electrical activity
of the top portion of the heart,
the atria.
That top chamber's just kind of quivering.
It's almost like an electrical storm happening.
The electrical signals that are going to
the bottom chamber are irregular
and so that's where we get this fast
and irregular heartbeat.
Typically, a person in atrial fibrillation
has a ventricular rate between 140 and 180 beats
per minute. That's awfully fast.
Not only is atrial fibrillation
common, the incidence increases with age.
By the time most people are around 80,
10% of the population
already has atrial fibrillation.
That is a huge number of people.
So for any primary care practice,
you will have patients in atrial fibrillation
with all sorts of different comorbidities.
Primary care physicians are often leading the way in terms
of identifying those patients to begin with.
Over long periods of time where
we didn't really have effective treatments,
we were just controlling symptoms.
But our rhythm-control
strategies have become more advanced.
And I think that
that's something that primary care
physicians should know about.
When we talk about atrial fibrillation,
there's different types.
There's paroxysmal,
which tends to occur off and on,
and typically is resolved by seven days.
Patients can go back into sinus rhythm
for a while
and then somewhere down
the line can go back into atrial fib.
There's persistent atrial fibrillation
where the atrial fibrillation
can last seven days or more,
and then there's permanent
atrial fibrillation
where the patient is not going back
to sinus rhythm.
When patients with atrial fibrillation
come to physicians,
there's several questions
that we have to ask ourselves
in order to figure out who is this patient?
How long has the patient had atrial fibrillation?
Well, in some cases,
we can't tell that
because the patient
may have gone into atrial fibrillation
and we don't know that.
We then have to ask,
does the patient
have any reversible causes
for the atrial fibrillation?
Hypothyroidism, alcohol use,
obesity, and sleep apnea.
These causes are treatable,
and once treated, the atrial
fibrillation tends to go away.
And then we move into the next question,
which is, okay,
if it's not something like that,
is this something that's
causing the patient's symptoms?
So we have to then get a really detailed history
about what kind of symptoms
the patient is experiencing.
And this can range
from actually none, where the atrial fibrillation
is just picked up on exam,
to shortness of breath,
exercise intolerance,
chest pain, lightheadedness, dizziness, etc.
And once you figure out
what kind of symptoms the patient has,
then you can start to work on
what's the right course of treatment.
Before we even talk about
whether we're going to engage
in a strategy
to eliminate recurrences of atrial fibrillation,
or allow a patient to stay in atrial fibrillation
and simply control the ventricular rate,
before we even do any of that,
we have to think thoroughly
about whether or not
this patient needs an anticoagulant
and which one.
The ineffective
mechanical contraction of the fibrillating atria
promotes stagnation of the blood.
Any time the blood is stagnant, a clot can form.
If it goes to an
artery in
the cerebral circulation,
a patient could have a stroke.
Some studies have suggested it may be a five-fold
increased risk of stroke
in a person who has atrial fibrillation.
And that's why an important principle
in the management of patients
with atrial fibrillation
is to assess their risk of stroke.
We do that with epidemiologic risk scores.
A common one used to be the CHA2DS2 score.
And now we use something
called the CHA2DS2-VASc score.
Typically, scores
of about two or higher
would warrant giving an anticoagulant,
The drug that we used for over six decades
was warfarin,
previously marketed under the trade
name Coumadin.
And that's a very effective form of anticoagulation,
but it has some challenges with it.
There are so many drug interactions.
Patients need to be careful
about how many green leafy vegetables they eat.
And there's, of course, the need to measure blood
tests about once a month.
More and more patients are being put on DOACs,
a direct oral anticoagulant,
rather than warfarin.
There are very few food and drug interactions
and we don't need to measure frequent blood tests.
So physicians need to get familiar
with the new oral anticoagulants, the DOACs.
After we've taken the time
to discuss the importance of anticoagulation,
we then talk about paths
for managing the arrhythmia itself.
Now, one path is to allow the patient to remain
in atrial fibrillation
or continue to have recurrent episodes of paroxysms
of atrial fibrillation,
make sure they're well anticoagulated
and that they're on drugs to increase
the filtering capacity of the AV node.
So that's rate control.
And that is selected as a treatment option
for specific patients
who are not terribly symptomatic
and have relatively infrequent episodes.
Another path is to actually control
the heart rhythm.
Quite often
we have patients take suppressive
antiarrhythmic drugs every day
to try and stabilize
the heart rhythm and prevent recurrences
of atrial fibrillation.
We do know that patients
don't like the concept
of having to take a drug every day.
And there's a small but finite risk
that the antiarrhythmic drugs
themselves could actually
destabilize their heart rhythm
and the most feared complication, of course, is
if the antiarrhythmic drug produces
destabilization in the lower chambers of the heart,
ventricular tachycardia occurring.
The other alternative that we have is ablation.
The fact that there is now
this catheter-based therapy,
to me is really the most exciting part of
what's new in atrial fibrillation.
At the core
of an ablation
procedure is what's called pulmonary vein
electrical isolation.
A lot of atrial fibrillation originates
around the pulmonary veins.
What the electrophysiologists want to do
is locate
the four pulmonary veins
in the left atrium and ablate around
those pulmonary veins.
They use a catheter to map
electrical impulses
and they use a second catheter
that can deliver either cooled temperature or
electricity to ablate and or burn the area.
By doing this,
they create a circle of burn around the vein
and that electrically isolates it.
This actually can help
prevent the impulse
for atrial fibrillation from traveling.
Now, not all atrial fibrillation
originates from the pulmonary veins,
so some of it can come from the coronary sinus,
some of it can come from the posterior wall.
And so the electrophysiologist
has to figure out where it's coming from.
And that's what they use
the mapping catheters for.
And then once they do figure that out,
they can use the ablation catheter
to electrically isolate the area.
It's a highly technology-
dependent procedure these days.
Unlike a cardiac surgeon,
we're not opening up the chest
and visualizing the heart directly.
We have to rely on all of these secondary
imaging techniques to be able
to see exactly where we are.
It's very Star Trek or Star Wars
or whatever high tech analogy you like to use.
It's not necessarily going
to prevent them
from having to
be admitted to the hospital
for an episode of heart failure
or something like that.
But with a successful ablation procedure,
the likelihood
of having recurrences of atrial fibrillation
is less compared
to, let us say, using an antiarrhythmic drug.
And many patients
find that their quality of life
is much better
after they've had
a successful ablation procedure.
Individuals who've got atrial fibrillation
that comes and goes
haven't been in an episode of atrial fibrillation
for a very long time, are younger.
Those are individuals
who have a greater chance
of a successful ablation procedure,
maybe 85% chance that that one ablation procedure
will eliminate recurrences
of atrial fibrillation,
at least for the foreseeable future.
So that means there might be a 15% chance
that a second procedure might need to be done.
The older patient,
individuals who have a very enlarged left atrium,
who are persistently, chronically
in atrial fibrillation,
it might be 60 or 70% chance of being successful.
What happens is
it has to do a little bit with the substrate
in a heart that has a lot
of fibrosis
where we can't get effective lesions,
for example,
or in those patients
who have the nonpulmonary vein sites
that are difficult to identify.
Those are some of the reasons we fail.
The most common reason we fail
is pulmonary vein reconnection.
The patient has the ability
to heal across those lines of block
and we need to go back in and perform
that touch up procedure
to seal off that fence
and achieve the long term isolation.
After an ablation procedure,
the patient may still have
a few episodes of palpitations
or maybe even very brief
episodes of atrial fibrillation.
That's all part of the healing process.
So think about the lesions that are being placed.
It takes time for scar
tissue to form in that area
and to really develop
that entrance and exit block
over the longer term.
So my patient's just had an ablation procedure.
They come back to me and the question is,
what do I do now?
First thing I have to
realize is
my patient may go back into atrial fibrillation
and may require more than one ablation attempt.
So that means I need to be monitoring
for atrial fibrillation
and whether I decide
I want to do that
with EKGs and physicals depends upon the patient.
The second thing I need to be aware
of is what to do
if the patient's on anticoagulation.
It's a very interesting question
as to whether or not we can
stop the administration of an anticoagulant.
We know that if they're off an anticoagulant
their risk of having an embolic
stroke is higher.
And since we cannot be absolutely certain
that there will be no recurrences
of atrial fibrillation,
the safest course of action
might be to just keep you on the anticoagulant.
Now, this is a shared decision-
making situation,
so we might have a patient
who is relatively young, very athletic.
They say, boy, if I can
avoid taking anticoagulants,
I would just feel safer
enjoying my leisure time activities.
And I understand the risk
and I'm sharing with you, physician, the
the decision
to actually stop the anticoagulation.
The next thing is I need to think
about potential complications
that could happen from the ablation procedure.
What kind of symptoms should send up some signals
that your patient
needs to go to the emergency room?
We've come a long way in understanding
atrial fibrillation.
We now have better drugs.
We now have ablation procedures
that can actually improve a patient's quality of life.
Electrophysiology
and treatment of atrial fibrillation
is this constantly evolving paradigm.
I am convinced that ten years from now,
the field is gonna be way different,
just as it is different than it was
ten years ago.
It's exciting to be part of that and
to witness it occurring.