Atrial Fibrillation (cont.)
Medical Author:
Noel G Boyle, MB, BCh, MD, PhD
Medical Treatment
Treatment for atrial fibrillation traditionally seeks three goals: to slow down
the heart rate, to restore and maintain normal heart rhythm, and to prevent stroke.
- Control rate: The first treatment goal is to slow down the ventricular
rate, if it is fast.
- If you experience serious clinical symptoms, such
as chest pain or shortness of breath related to the ventricular rate, the
health care provider in the emergency department will decrease your heart
rate rapidly with IV medications.
- If you have no serious symptoms, you may be given
medications by mouth.
- Sometimes you may require a combination of oral
medications to control your heart rate.
- Restore and maintain normal rhythm: About half the people with newly
diagnosed atrial fibrillation will convert to normal rhythm spontaneously in
24-48 hours. However, atrial fibrillation typically returns.
- As already mentioned, not everyone with atrial
fibrillation needs to take medication to maintain normal rhythm.
- The frequency with which your arrhythmia returns
and the symptoms it causes partly determine whether you receive
rhythm-controlling medication, which is usually called anti-arrhythmia
medication.
- Medical professionals tailor each person's
anti-arrhythmia medication(s) carefully to produce the desired effect
without making the dose too high.
- Most of these medications cause unwanted side
effects, which limit their use. These medications should be discussed with a
doctor.
- Prevent stroke: Stroke is a devastating complication
of atrial fibrillation. It occurs when a piece of a blood clot formed in the
heart breaks off and travels to the brain, where it blocks blood flow.
- Coexisting medical conditions, such as
hypertension, congestive heart failure, heart valve abnormalities, or
coronary heart disease, significantly increase the risk of stroke. Age older
than 65 years also increases the risk of stroke.
- Most people with atrial fibrillation take a
blood-thinning drug called warfarin (Coumadin) to lower this risk. Warfarin
blocks certain factors in the blood that promote clotting. Acutely, the
initial blood thinner is IV or subcutaneous heparin to thin your blood
rapidly, then a decision is made whether you need oral warfarin.
- People at lower risk of stroke and those who cannot
take warfarin may use aspirin. Aspirin is
not without its own side effects, including bleeding problems and stomach
ulcers.
Defibrillation (cardioversion): This
technique uses electrical current to "shock" the heart back to normal sinus rhythm. This is sometimes called DC
cardioversion.
- This is done by connecting a device called an
external defibrillator to the chest with patches or paddles.
- When this is performed in a hospital, an anesthetic
is given first so the patient is fully sedated and asleep during the procedure
because the electrical discharge is painful.
- Defibrillation works very well; more than 90% of
people convert to sinus rhythm. It is most successful if your atrial
fibrillation is new (that is, hours, days, or a few weeks). For many, however,
this is not a permanent solution because the arrhythmia often comes back.
- Defibrillation increases the risk of stroke and thus
requires pretreatment with an anticoagulant medication.
Catheter ablation (radiofrequency [RF] ablation). This technique electrically
burns/destroys some of the abnormal conduction pathways in the atria.
- The catheter delivers radiofrequency energy, which
interrupts (ablates) a portion of the abnormal electrical conduction pathway.
This inactivates the abnormal pathway to provide more consistent flow of
electrical impulses.
- In atrial fibrillation, RF ablation is a relatively new procedure and is
currently best reserved for patients who have tried antiarrhythmic medications
without success or who cannot take these medications. Current success rates are in
the 60-70% range. However, serious complications associated with the procedure
can occur, and these need to be discussed carefully with the doctor before
undergoing this procedure.
Pacemaker: A pacemaker is an electronic device that prevents slow heartbeats,
and may reduce the likelihood of atrial fibrillation in a small number of
patients. The artificial pacemaker takes the place of the "natural pacemaker,"
the SA node, supplying electrical impulses to keep the heart beating in a normal
rhythm when the SA node no longer can.
- The pacemaker is usually implanted in both the right
atrium and right ventricle. The goal is to override your own atrial
fibrillation with a new atrial electrical pacemaker, and turn off your own,
native arrhythmic focus. A minority of patients are offered this technique
currently. This is a more complex technique and device, and no long-term data
regarding success is available yet.
- A pacemaker is occasionally used in conjunction with
radiofrequency ablation of the AV node, which disconnects the atria from the ventricle, so rapid heart rates cannot be conducted to the ventricles. This
creates complete heart block, and now the ventricles are totally dependent on
the artificial, electrical pacemaker in the right ventricle.
- Some machines and devices in your surroundings can
interfere with the production of electrical impulses by your pacemaker. For
example, airport security devices can deactivate pacemakers. Be sure you are
familiar with which types of devices may have this effect, and avoid those
devices.
- Carry an identification card that shows that you have a pacemaker. You will
need to present this identification when going through airport security and ask
to be hand searched as some security machines may inactivate pacemakers. Always
tell any medical or dental personnel that you have a pacemaker.
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