Brian Olshansky, MD, Professor of Internal Medicine
University of Iowa Hospitals and Clinics
Creation Date: May 2001
Last Revision Date: May 2001
Peer Review Status: Internally Peer Reviewed
Atrial fibrillation is the most common arrhythmia requiring treatment in the United
States. Approximately 2.2 million individuals in this country have atrial fibrillation.
What causes atrial fibrillation?
Atrial fibrillation is associated with many cardiac conditions, including cardiomyopathy,
coronary artery disease, valvular heart disease, ventricular hypertrophy and
other associated conditions. Atrial fibrillation has been associated with hyperthyroidism,
acute alcohol intoxication, changes in the autonomic nervous system and is common
after cardiac surgery. The most common condition associated with atrial fibrillation
is high blood pressure. Some people have atrial fibrillation with no obvious
source or associated condition. This is more frequent in younger people and
it is called "lone" atrial fibrillation. It is likely that people who have this
form of atrial fibrillation have had some inflammatory process or trauma to
the atrium. Some people have a focal source that originates from the pulmonary
Is atrial fibrillation associated with a heart attack or a stroke?
Atrial fibrillation is a very rapid irregular rhythm in the top two chambers
of the heart. If one were to look at the heart as it were fibrillating, it would
look like a bowl of Jell-O quivering. A heart attack is when an artery supplying
blood to the heart blocks off causing damage to the heart muscle. A stroke occurs
when an area of the brain does not get enough blood supply, in some cases due
to a blocked artery supplying blood to the brain. This leads to brain damage
and neurologic dysfunction. Atrial fibrillation can be associated with a heart
attack or a stroke. Atrial fibrillation is a common cause of stroke in the elderly
and up to 30 percent of the strokes in individuals over the age of 75 are due
to atrial fibrillation. The reason that atrial fibrillation can be associated
with, or cause, a stroke is because blood clots tend to form in the upper chambers,
so-called atria, of the heart and these blood clots can break off and travel
throughout the body, plugging up blood vessels. 25% of the blood goes to the
brain in most cases, it is common that a blood clot, if it travels, will travel
to the brain. It can also travel to the heart and clog up a vessel creating
a heart attack or it can travel to any other area of the body causing a blocking
in an artery--to the leg, for example, in the eye or any other organ. The risk
of blood clots caused by atrial fibrillation increases in the following conditions:
1. hypertension, 2. heart failure, 3. diabetes, 4. increasing age.
Can a person be cured of this? Can it go away?
Yes. One form of atrial fibrillation that is treatable is so-called paroxysmal
atrial fibrillation. This form of atrial fibrillation is more common in younger
people and in people without serious underlying structural heart disease. In
fact, this form of atrial fibrillation often occurs without any other underlying
heart disease present. This paroxysmal form occurs when episodes of atrial fibrillation
come for a short period of time and go away suddenly, to return later. This
form is often associated with frequent extra beats in the atrium. In the electrophysiology
laboratory, much the same kind of a place as a cardiac catheterization laboratory,
catheters with electrodes on the tips can be placed into the heart to "map"
the initiation of atrial fibrillation. The technology in this regard is advancing
rapidly. Much of this form of atrial fibrillation originates from the pulmonary
veins so the procedure is quite involved. It requires "transeptal puncture"
to get the catheters to the left side of the heart. When the source is identified,
an application of radiofrequency energy, or more recently, ultrasonic energy,
is delivered to eliminate the spot creating the problem. For this form of atrial
fibrillation, the success rate has been reported to be as high as 80 percent.
There are several important concerns using this number as a benchmark: 1. the
procedure is really still new and somewhat experimental. 2. Not all electrophysiologists
and not all centers have the expertise to perform this. 3. The long-term success
rate is not clear because the follow-up has been in terms of months rather than
years. 4. There may be multiple spots that trigger atrial fibrillation and they
might not all be obvious at the time of the evaluation. 5. There are some potential
risks of this procedure: one risk includes so-called pulmonary vein stenosis.
If multiple applications of energy are delivered into the site that triggers
atrial fibrillation and if these sites are from the pulmonary vein, then it
is possible to cause blockage of the pulmonary vein and this is a very dangerous
situation. I would not want to dissuade you from therapy since this therapy
can be curative, but there are significant risks such that it would make sense
to consider other therapies first to keep the rates low or to supress episodes
of atrial fibrillation. Atrial fibrillation also can be cured by a surgical
procedure known as a MAZE procedure. Percutaneous approaches in the electrophysiology
laboratory have been tried to recreate this MAZE procedure to cure atrial fibrillation
in people who have it more chronically, or persistently, than a person who has
paroxysmal atrial fibrillation. Atrial fibrillation can also go away on its
own in some people. It tends to do this when there is a specific trigger such
as coronary artery bypass surgery, hyperthyroidism, pericarditis, alcohol intoxication
(or other stimulants such as some of the over-the-counter supplements, and even
caffeine), other acute illnesses that cause extreme vomiting, and some conditions
that lead to overexertion.
Is it safe to work out with this condition?
In general, it is not a good idea to workout too vigorously with atrial fibrillation
unless you have been carefully evaluated for underlying heart conditions by
a doctor. Some people who have atrial fibrillation have significant problems
with their heart and with exercise, the heart rate can race tremendously during
atrial fibrillation, thereby exacerbating the underlying heart condition and
may lead to problems such as very low blood pressure, heart failure or a loss
of consciousness. If the problem of atrial fibrillation has been well managed
so that the rate is under control, or the rhythm is under control, it is possible
to go back to standard physical activity in many cases. In fact, there are several
professional athletes, including basketball players, who have atrial fibrillation
present at times.
Is there a common drug therapy?
There are several approaches to atrial fibrillation management with drugs:
1. Drugs to control the heart rate during atrial fibrillation. 2. Drugs to keep
someone in sinus rhythm. 3. Drugs to prevent blood clots that can happen from
Let's consider the first category of drugs: Drugs to control heart rate include
medications known as beta-blockers, calcium channel blockers and digoxin. Sometimes
these drugs are given intravenously, but they are also available orally and
these drugs are used to prevent the heart rate from speeding up too much during
atrial fibrillation with exercise and they need to be adjusted so the rate does
not get too slow at rest.
The second class of drugs to maintain normal rhythm include so-called antiarrhythmic
drugs. Some of these drugs need to be started in the hospital. Some of the older
drugs include Quinidine, Procainamide, Disopyramide, Flecainide, Propafenone,
Sotalol, Amiodarone and a new drug known as Dofetilide. These drugs are not
all approved by the FDA but all have been used for atrial fibrillation by doctors.
Each one has its own set of side effects and benefits. Amiodarone is the most
potent, but it has a large number of long-term side effects possible. Flecainide
and Propafenone are not to be given to anyone who has an underlying heart condition.
The third types of drugs are blood thinners to prevent stroke and blood clots.
These medications include Heparin and Warfarin. With this large compendium of
medications, a doctor may select several, depending on the severity of the symptoms,
the age of the patient, the presence of underlying heart conditions and response
to other medications, the severity of the episodes and other risk factors for
I read the venom of the tarantula spider is being used to develop a drug
to treat this condition, is there anything to it?
Yes, there is something to the use of tarantula spider venum. No drug has yet
been developed but a report in the journal Nature on January 4, volume
409, page 35, describes the response of atrial fibrillation to this toxin. It
works in a different way than the other medications so far developed and it
works on stretch channels in the heart. If this proves to be effective, it may
provide insight into causes of atrial fibrillation and the development of potentially
new useful therapies.
Is it true that some people have no symptoms until they have a stroke?
Yes, it is true. For some people, atrial fibrillation represents no more than
a new, annoying palpitation. For other people, it can be the cause for a stroke
but the process might have been unrecognized until that point. The older you
are, and the more risk factors you have for stroke, as I mentioned earlier,
the greater the chance that without being on a blood thinner, that atrial fibrillation
will cause a stroke. With several risk factors present, an older person can
have a risk factor for stroke as high as 17 percent each year. One issue about
atrial fibrillation is that there are those that have it and do not even recognize
that it is present. Stroke can be caused by atrial fibrillation even in younger
individuals and it is one of the potential causes for stroke in which no obvious
cause can be diagnosed.
Is Digitalis still used to treat irregular heartbeat? It's been around forever!
Digitalis is one of the treatments used for patients with atrial fibrillation.
It comes from the foxglove plant. Digitalis is used mainly to control the rate
of the heart during atrial fibrillation. It is not our best drug to control
the rate but may be more useful in elderly, less active patients and in patients
who cannot take a beta-blocker or a calcium channel blocker. It may also be
useful in patients who have atrial fibrillation and congestive heart failure.
Digitalis at high doses can be potentially toxic and in anyone who has kidney
problems, or is taking Quinidine, or Verapamil (a calcium channel blocker),
the levels of Digitalis can increase substantially.
Can over-the-counter drugs cause irregular heartbeats? Do symptoms go away
when the use of the OTC is discontinued? Or can you cause permanent damage?
Regarding the first question, yes, some over-the-counter drugs can cause irregular
heartbeat and some OTC drugs can be associated with atrial fibrillation. The
ones of concern are the ones that include adrenalin analogs. Adrenalin is made
in the body and it increases the heart rate and blood pressure. Pseudoephedrine
is one such compound. This is present in many cold and decongestant preparations.
It is important to recognize that some weight loss products and some over-the-counter
herbal compounds contain an herb known as ma huang. This herb has ephedrine
in it. It is important to look at the ingredients in some of these weight loss
products or OTC herbal products because this herb can cause irregular heart
rhythm and has been associated, in some instances, with sudden death due to
cardiac arrest. If an irregular rhythm, or atrial fibrillation, is triggered
by an OTC preparation, it may persist for some period of time. But generally,
it goes away on its own. However, once atrial fibrillation starts, and if it
is not corrected by intervention and does not go away on its own, over time,
the presence of atrial fibrillation in which the rate of the heart is not kept
under control means there can be permanent damage to the heart.
Are women more likely than men to have an irregular heartbeat or vice versa?
Actually, with atrial fibrillation, it's men who have more disease. However,
women are more likely to feel their irregular heart rhythm and to have irregular
heart beats. Younger people with atrial fibrillation tend to be men and tend
to be highly symptomatic with their episodes of atrial fibrillation. Younger
women tend to feel extra beats both in the upper and lower chambers of the heart.
Older women tend to be more likely, than men, to have atrial fibrillation where
it is reversed at a younger age.
Are there any underlying conditions that make a person more prone to an
Yes. While an irregular heart beat can occur independent of any other heart
condition, it is worth having the problem checked out because an irregular heart
rhythm may be a sign of a concerning underlying heart condition such as cardiomyopathy,
heart failure, coronary artery disease, valvular heart disease and other conditions
Do things like caffeine or intensive exercise enhance a heart arrhythmia?
Caffeine and intense exercise are some of the triggers for irregular heart
beats and in particular, atrial fibrillation. It is important to try to relate
any irregular heart beat and the presence of atrial fibrillation to what is
going on at the time. Because some people will go to a doctor and mention that
they drink, for example, a large amount of caffeinated beverages, and have atrial
fibrillation. The doctor may restrict them unnecessarily from drinking caffeinated
beverages, and there may be no benefit in doing so. On the other hand, if the
individual recognizes a relationship between drinking caffeinated beverages
and irregular heart rhythms, then it would make perfect sense to abstain from
this. Similarly, with exercise and alcohol ingestion.
Is tachycardia the same thing?
Atrial fibrillation is a form of tachycardia. Tachycardia really means a fast
heart rhythm. There are many forms of tachycardia. Most people think of tachycardia
as a supraventricular tachycardia. But, there are many other forms of tachycardia.
Supraventricular tachycardia is a specific rapid rhythm often due to a spot
in the top chamber of the heart that is beating rapidly, or it is due to an
abnormal electrical pathway that allows for a kind of "short circuiting" of
the heart. These pathways can be eliminated by ablation techniques in the electrophysiology
laboratory. Tachycardia can be a normal response to exercise, this is known
as sinus tachycardia. The heart rate will race simply because of the exercise.
Another form of tachycardia, a potentially life-threatening form, is known as
ventricular tachycardia. It is when the lower chambers of the heart are racing
If you are diagnosed and treated for atrial fibrillation, and experience
fast heart rhythm, could you take additional meds?
Yes, you can take additional medication but is very important to realize that
the medicines that are available for atrial fibrillation can interact with each
other in a bad way. One reason to take additional medicines would be to try
to stop the rhythm. Fleconaide and Propafenone, two antiarrhythmic medications
are sometimes prescribed to be taken only when the rhythm occurs. This would
be safe as long as these medications are indicated for that specific individual
(they would not be for an underlying heart condition) and you should never mix
two antiarrhythmic medications. Sometimes medications, which are given, are
given specifically to keep the heart rate under control. If the heart rate gets
faster, it would be appropriate to take a little extra of these medications.
It is unlikely that taking a blood thinner, specifically at the time of the
onset of atrial fibrillation, would be of any use.
What we have discussed today is the problem of a serious condition known as
atrial fibrillation. This common medical problem has many different presentations
and associations with other conditions. There are new advances in therapies,
some of which can cure atrial fibrillation, which are being investigated further.
Medical therapy often requires multiple adjustments until the proper prescription
is achieved for any given individual. Any therapy that is used for atrial fibrillation
has potential risks and must be prescribed on an individualized basis. A "one-size-fits-all"
for atrial fibrillation simply does not work. Newer therapies are being developed
at a rapid rate and it is likely that in the next five to ten years, cures for
atrial fibrillation will be common and perhaps of lower risk than they are now.