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Atrial Fibrillation
Part II
Hector Fontanet, M.D., FACC
with
Marie Cheine, Medical Writer
August 26, 2005
In our last article, we discussed atrial fibrillation, the most common form
of irregular heart rhythm. The goals of treatment for atrial fibrillation
are prevention of stroke, control of heart rate and restoration of normal
rhythm. As previously reported, the prevention of stroke in nearly all
patients with atrial fibrillation will be necessary. This is carried out by
the anticoagulation (blood thinning) with Coumadin® or Warfarin. It has been
shown in clinical trials that treatment with aspirin is not sufficient to
prevent stroke in this class of patients. Common medications for rate
control include calcium channel blockers, beta-blockers and digoxin.
Although this group of medications is effective in controlling the heart
rate they are not usually effective in restoring normal heart rhythm.
Medications that convert and maintain normal rhythm are called
antiarrhythmics. Long term options for treatment are dependent upon the
underlying cause (etiology) of each individual case.
Based on the results recently learned from various clinical trials, most
asymptomatic patients will be best managed with rate control and
anticoagulation only, avoiding potential side effects of antiarrhythmics.
However, some patients remain symptomatic after rate is controlled. For
these patients, or patients who have underlying heart disease, the use of
antiarrhythmics has advantages, most importantly the improvement of quality
of life, improving heart function in patients with heart failure and
potentially allowing the discontinuation of anticoagulation therapy.
Antiarrhythmics, nevertheless, are a complex class of medications and carry
risk and potential side effects. The most effective medication in this class
is Amiodarone, which works by slowing nerve impulses in the heart and acting
directly on the heart cells to synchronize the electrical impulses. These
medications should be used judiciously and patients must be closely
monitored while using them. In some cases, these medications can cause life
threatening rhythm disturbances in patients with certain heart conditions.
For this reason, your doctor may elect to start this type of medication in
the hospital under careful observation.
In cases where symptoms or side effects remain intolerable or a patient
fails medical therapy, other therapies such as electrical cardioversion
(electric shock to restore normal rhythm) or radiofrequency ablation can be
considered. Radiofrequency ablation is an invasive procedure performed in
the hospital in the cardiac catheterization laboratory. During this
procedure, x-rays are utilized to position a special catheter at the exact
place in the heart where the abnormal rhythm is generated and
“microwave-like” energy is transmitted to destroy this area and prevent the
abnormal rhythm. Radiofrequency ablation is only performed by
electrophysiologists who have special training in this procedure. Your
physician can refer you to an electrophysiologist with this expertise if
necessary.
In summary, atrial fibrillation is a common non life threatening rhythm
disturbance of the heart. The approach for treatment varies with each
patient. Whether it is rate control or restoration of normal rhythm, with
any one of many modalities, the risks and benefits of medical and/or
invasive treatment must be weighed carefully and discussed in detail with
your physician.
Sources:
American Heart Association
Cleveland Clinic Journal of Medicine
Electrophysiology Division University of California San Francisco
Heart Rhythm Society
Medline Plus
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