|
Atrial Fibrillation Treatment Center
What is Atrial Fibrillation?
Atrial fibrillation is the most common
irregular heart rhythm in the United States. Atrial fibrillation is an
abnormal heart rhythm originating in the atria. Instead of the impulse
traveling in an orderly fashion through the heart, many impulses begin
and spread through the atria and compete for a chance to travel through
the AV node. This causes a rapid and disorganized heartbeat. The rate of
impulses through the atria can range from 300 to 600 beats per minute.
The AV node limits the number of impulses it
allows to travel to the ventricles. The resulting heart beat is
irregular, ranging from about 50 to 150 beats per minute.
What Causes Atrial Fibrillation
Most common causes
- Hypertension (high blood pressure)
- Coronary artery disease
- Heart valve disease
- Heart surgery
- Chronic lung disease
- Heart failure
- Cardiomyopathy
- Congenital heart disease
- Pulmonary embolism
|
Less common causes
- Hyperthyroidism
- Pericarditis
- Viral infection
|
In at least ten percent of the cases, no underlying
heart disease is found. In these cases, AF may
be related to alcohol or excessive caffeine use, stress,
certain drugs, electrolyte or metabolic imbalances, or
severe infections. In some cases, no cause can be found.
The risk of AF increases with age, particularly after age 60.
Treatment of Atrial Fibrillation
At Winthrop's Atrial Fibrillation Treatment
center treatment of Atrial
Fibrillation is individualized
to patients' needs.
Lifestyle, age, and co-existing
medical conditions are all taken
into consideration.
Anticoagulation
Anticoagulation is one of the of
the fundamental and important treatment
modalities for Atrial Fibrillation. There is a
strong association between stroke and
Atrial fibrillation.
Numerous studies have shown the
benefit of anticoagulation with
warfarin in patients with
Atrial Fibrillation. One of the
drawbacks to taking warfarin is
that the patient is required to
have monitoring bloods tests (INR)
on a regular basis to adjust the
dosage and the blood thinning
effect of medication. The goal
of therapy is to maintain the
patients INR between 2 and 3.
If it is too high the patient may
have a bleeding problem. If it is too low
the patient is not protected
against a possible stroke. For patients with an absolute
contraindication to warfarin,
aspirin therapy is an option;
however, the benefit is only about half
that of warfarin.
Rate Control
One
of the medical therapies used in
the treatment of Atrial
Fibrillation is rate control. The choice of
agent should be based on the
individual patient but in general
beta-blocker therapy, calcium
channel blockers or Digoxin can be
used to achieve this goal.
Rhythm Control
Antiarrhythmic Medications
While part of the medical
therapy for Atrial Fibrillation
is targeted to control the rate
of the heart, other medication
may assist in getting the heart
to covert or maintain a normal
regular sinus rhythm. These
drugs may include quinidine, procainamide,
disopyramide, flecainide,
propafenone amiodarone,
sotalol, and dofetilide. The
efficacy of these antiarrhythmic
drug ranges between 50% and 80%. The
selection of which drug(s) are used
is based on the individual
patient's medical and cardiac
assessment.
Electrical Cardioversion
If medications are not able to
control atrial fibrillation,
cardioversion may be required.
Cardioversion frequently
restores a normal rhythm,
although its effect may not be
permanent. After a short-acting
anesthetic is given, a small
electrical shock is delivered to
the patient's chest wall to "short
circuit" the heart and have the
heart's normal pacemaker take
over. This can restore a
normal rhythm.
Radiofrequency
Ablation
Studies have shown that
almost all atrial fibrillation
signals come from the four
pulmonary veins. During the
Radiofrequency Ablation
procedure special catheters are
inserted into the heart. Two
catheters are inserted into the
right atrium and two into the
left atrium. One catheter in the
left atrium is used to map or
locate the abnormal impulses
coming from the pulmonary veins.
The other catheter is used to
deliver the radiofrequency
energy to ablate, or create
lesions outside the pulmonary
veins. The procedure is repeated
for all four pulmonary veins.
The lesions heal and within 4 to
8 weeks, form a circular scar
around the pulmonary veins. The
scar blocks any impulses firing
from within the pulmonary veins,
thereby "disconnecting" the
pathway of the abnormal rhythm
and curing atrial fibrillation.
|