Treatment of Atrial Fibrillation (AFib)
Since many of the treatment goals relate to the relief or
improvement of symptoms, doctors spend a great deal of time inquiring
about how patients feel.
Treatment strategies are generally focused on improving the
patient’s symptoms. In general, control of the heart rate in atrial
fibrillation is the first objective. For example, if the patient's
heart rate is too rapid, one would use medication to control that rate.
If the patient remains symptomatic, such as fatigue, shortness of
breath, dizziness or lightheadedness, despite improved control of the
heart rate, one may consider trying to prevent atrial fibrillation
from occurring. This may be done with additional medication or in
some cases with catheter ablation.
For most patients, the care received is based on symptoms and how
interested the patient is in preventing these symptoms. This
intervention, whether it consists of medications or catheter ablation,
may involve some side effects and potential risk. The patient is
usually significantly involved in this decision.
For patients with atrial fibrillation that have minimal symptoms
with or without the need for medication to control the rate, the need
for maintaining normal rhythm is much less.
Asymptomatic patients
A few patients are asymptomatic, meaning they do not present
symptoms such as chest pain, dizziness or fatigue.
Are there circumstances in which the asympotatic patient still might
want to prevent atrial fibrillation or restore sinus rhythm?
In selected cases, probably representing a minority of patients, one
is uncertain whether the patient has symptoms related to atrial
fibrillation. This is potentially more common in patients who are in
atrial fibrillation continuously, since they may to some extent adjust
to the atrial fibrillation. It is possible that some patients have
adapted so well that they are not aware of these symptoms. For
example, a patient may answer that, yes, it is true that there is more
fatigue than a year ago, but this is often attributed to increased age
or some other medical problems. When asked whether the patient can
exert as much as previously, sometimes the answer is, “I am mainly
limited by my hips or knees.”
The options in such situations are to continue to observe the
patient for worsening of symptoms or clear symptoms. The alternative
would be to try to maintain normal rhythm on a somewhat temporary
basis, to see whether the patient has fewer symptoms in sinus rhythm.
This approach gives the patient the option then, once one has restored
sinus rhythm for a period. In some cases, the patient will continue
to say there is no difference in how they feel. In such cases, one may
decide to not pursue maintaining sinus rhythm. On the other hand, if
the patient is surprised and in fact remarks that they have more
energy, then strategies to restore normal rhythm may be pursued.
In some cases, there may be evidence of decreased heart function.
There may be clear causes of decreased heart function, but in other
cases there may not be. Examples of apparent reasons for decreased
heart function might be a known heart attack or myocardial
infarction. There also may have been decreased heart function prior
to the onset of atrial fibrillation, without any subsequent change in
the degree of dysfunction. In such cases, atrial fibrillation would
not be likely to play such a large role in impairing heart function.
On the other hand, if the heart function has been previously normal,
then was only noted to be abnormal on discovery of atrial
fibrillation, it is possible that restoration of normal rhythm may
result in improved heart function.
One known mechanism of how atrial fibrillation impairs heart
function is the effect of heart rate on the heart function. It is
well described that excessive ventricular rate in atrial fibrillation
may significantly impair left ventricular function. Sometimes this is
called a tachycardia myopathy, indicating tachycardia, meaning fast
heart rate, and myopathy, meaning an abnormality of the heart muscle
itself. This phenomenon is felt to be due to the direct effects of
the rapid rate on the heart tissue. In most situations, there is
normalization or near normalization of the heart function in such
circumstances. However, there may be a combination of effects and the
heart function may not recover.
The ability to restore left ventricular function back to normal is
extremely important, since left ventricular dysfunction can be a major
cause of future need for hospitalizations or fluid retention or what
is called heart failure. It also may lead to decreased overall
survival. Restoration of normal rhythm, even the absence of apparent
symptoms, in the setting of unexplained dysfunction of the heart, may
be very important to the overall patient condition.
There has been the hypothesis that simple restoration of sinus
rhythm improves the overall outcome independent of symptoms. There
were a number of studies, including several extremely large studies in
patients with atrial fibrillation, which examined the role of
maintaining normal rhythm, the so-called rhythm control approach. The
largest study was called the AFFIRM study, which randomized patients
to control of their rhythm, medications designed to restore normal
rhythm and medications that simply control the rate during atrial
fibrillation. This study and other similar studies did not show any
benefit of the rhythm control strategy and even shows a slight trend
toward harm. These patients were mainly 70 years of age or older and
these results may not be applicable to younger patients. In this
study, only 50% of patients in the rhythm control arm had
anticoagulation with warfarin, where nearly all the patients in the
rate control arm were on warfarin. There is a higher ischemic stroke
risk in the rhythm control arm, despite the fact that on the majority
of visits they were in normal rhythm.
Therefore, many physicians have concluded that it is insufficient to
determine that a patient with atrial fibrillation is in normal rhythm;
one must consider the patient still to have a risk of blood clots and
stroke and therefore patients should be treated with anticoagulation appropriately.
At present most physicians and current national guidelines indicate
that patients should continue on anticoagulation based on their CHADS2
score. Thus, even if the patient remains in sinus rhythm on an
antiarrhythmic agent or after catheter ablation, current
recommendations are that anticoagulation should be continued if the
CHADS2 score is two or more.
Learn more about the following treatment options for atrial fibrillation: