Atrial Fibrillation (Afib)
How your heart normally works
Your heart pumps blood to the rest
of your body. During each heartbeat, your two atria contract, followed by your two
lower chambers (ventricles). These actions, when timed perfectly, allow your
heart to work as an efficient pump. Your heart’s electrical system controls the
timing of your heart’s contractions. And your sinoatrial (SA) node is normally
in charge of that electrical system. This node is located in your right atrium.
When your SA node fires an impulse, electrical activity spreads through your
right and left atria (“atrium” is singular and “atria” is plural). Both atria
then contract and force blood into your ventricles.
The impulse then travels to the
atrioventricular (AV) node, located near the middle of your heart. From there,
the impulse moves to your ventricles, causing them to contract and pump blood
out of your heart to your lungs and the rest of your body. This process repeats
with every heartbeat. The SA node directs the timing of the electrical impulses
and keeps your heart pumping smoothly.
You can think of your SA node as the
conductor of an orchestra. Your SA node is responsible for keeping your heart
beating at the proper pace and rhythm. Likewise, an orchestra conductor directs
all the musicians to keep the music flowing at the right tempo, sometimes
faster and sometimes slower.
Normally, your SA node adjusts to
your level of activity. For example, it increases the rate of impulses when you
exercise and decreases the rate when you sleep. With the SA node conducting
your heart’s rhythm, you are in “normal sinus rhythm.” This means your heart is
beating at a regular rhythm and pace, about 60 to 100 times per minute.
What happens when you’re in Afib
If you have atrial fibrillation,
your SA node isn’t directing your heart’s electrical rhythm. Instead, many
different impulses rapidly fire at the same time, causing a fast, chaotic
rhythm in your atria. As a result, your atria can’t contract or pump blood
effectively into your ventricles. Your ventricles contract irregularly, causing
a rapid irregular heartbeat.
It’s as if in the middle of a
concert, two more conductors walked onto the stage and started waving their
batons. The musicians would no longer know who to follow or what to do. The
music would lose its rhythm and harmony.
Fortunately, there are many ways to
bring back your heart’s rhythm and harmony if you have Afib. It all starts with
a visit to your healthcare provider, who can run some tests and make a
diagnosis.
How common is atrial fibrillation?
Some researchers have called Afib
the “new cardiovascular disease epidemic of the 21st century.” Afib is
especially common among older adults. Over 33 million people age 55+ have been
diagnosed globally. Estimates predict that 12 million people in the U.S. will
have Afib by 2030. Afib causes nearly half a million yearly hospitalizations in
the U.S. and leads to more and more deaths with each passing year.
Who does atrial fibrillation affect?
While Afib can affect anyone, it’s
more common among people of European descent. However, Black people who have
Afib are more likely to have serious complications such as stroke or heart
failure. People assigned female at birth (AFAB) are more commonly diagnosed
than people assigned male at birth (AMAB).
What causes atrial fibrillation to
start?
Changes or damage to your heart’s
tissue and electrical system cause atrial fibrillation. Usually, coronary
artery disease or high blood pressure causes those changes. Often a trigger
heartbeat causes atrial fibrillation to begin. But sometimes it’s hard to know
the cause of that triggered heartbeat. For some people, there is no
identifiable cause. Research is constantly providing new information to help us
learn more about the
Afib often runs in families. So, if
a close family member has Afib, you have a “family history” and therefore a
higher chance of developing it, too.
Can atrial fibrillation be caused by
anxiety?
We don’t fully know the connections
between atrial fibrillation and anxiety. Research has identified Afib as a
cause of anxiety (if you have Afib, you might worry about your symptoms or
quality of life). But few studies have explored anxiety as a cause of Afib. We
do know that anxiety can raise your risk of cardiovascular disease and causes a
48% higher risk of cardiac death. However, we need more research to find out if
anxiety disorders can cause Afib.
How is atrial fibrillation
diagnosed?
To diagnose atrial fibrillation,
your healthcare provider will first ask you some questions. You’ll share
information about your diet and physical activity, family history, any symptoms
you’ve noticed and risk factors. It’s OK if you don’t know all the answers but
share as much as you can. Your experiences and knowledge are essential tools to
help your provider make a diagnosis. Your provider will then give you a
physical exam that includes:
Listening to your heart rhythm with
a stethoscope.
Checking your pulse and blood
pressure.
Checking the size of your thyroid
gland to identify thyroid problems.
Looking for swelling in your feet or
legs to identify heart failure.
Listening to your lungs to detect
heart failure or infection.
This exam will help your provider
understand your baseline health and how your body is functioning.
Tests to diagnose atrial
fibrillation
In addition to the physical exam,
your provider may run some tests to make an atrial fibrillation diagnosis.
These tests include:
Electrocardiogram (EKG or ECG). An
EKG is usually the first test. It’s painless and takes about three minutes. It
measures and records your heart’s electrical signals and allows your provider
to see if your heart is beating normally.
Echocardiogram (echo). An echo uses
ultrasound technology to show your heart’s movement. It can reveal problems
with blood flow and heart muscle contractions.
Blood tests. Sometimes, imbalances
in our blood can cause Afib. Simple blood tests can show your potassium and
thyroid hormone levels and can help your provider choose the best medicines for
you based on your liver and kidney function.