What is chemical cardioversion?
Cardioversion is a procedure used to return an abnormal heartbeat to a normal rhythm.
It's used to treat a very fast or irregular heartbeat (arrhythmia). In chemical cardioversion,
medicines are used to get the heart back to a normal rhythm. It's different from electrical
cardioversion. This is where an energy shock is used to bring back a normal heart
Normally, a special group of cells start the electrical signal of your heartbeat.
These cells are in the sinoatrial (SA) node in the upper right chamber of the heart
(right atrium). The signal quickly travels down the heart’s conducting system on its
way to the ventricles, the 2 lower chambers of the heart. As it travels, the signal
triggers nearby parts of the heart muscle to contract. This helps the heart contract
in a controlled way.
Many problems can upset the signaling pathway and lead to abnormal heart rhythms.
The heart might beat very quickly. As a result, the heart doesn't have enough time
to fill with blood between beats. This can keep your heart from pumping enough blood
to the body. Some abnormal heart rhythms may raise your risk for stroke. Some also
raise the risk for life-threatening rhythms that can lead to sudden death. Cardioversion
upsets the abnormal signaling. It allows the heart to reset itself back into a normal
rhythm, like when you reboot your computer to reset it.
Why might I need a chemical cardioversion?
Chemical cardioversion can help to treat a number of different abnormal heart rhythms.
It's sometimes used to treat atrial fibrillation (AFib). With this condition, the
atria of the heart quiver instead of contracting properly. People with AFib may have
shortness of breath, fatigue, and a very fast heartbeat. They are also at increased
risk for stroke.
Your healthcare provider may suggest some type of cardioversion if this is your first
episode of AFib. They may also advise it if you have constant AFib especially with
severe symptoms. Your healthcare provider may try a chemical cardioversion first.
You don't need sedation and the procedure is less upsetting than an electrical cardioversion.
If this treatment does not work, your healthcare provider may do an electrical cardioversion.
It's more likely the electrical shock will work after you have tried chemical cardioversion.
Chemical cardioversion can also help treat other abnormal heart rhythms. These include
atrial flutter, supraventricular tachycardias, and ventricular tachycardia (VT). All
these heart rhythms can cause heart rates that are too fast. This can prevent the
heart from pumping enough blood.
If your symptoms are mild, your healthcare provider may suggest that you not have
cardioversion. They may also advise against it if you have had AFib for a long time.
It may also not be advised if you are an elderly adult or have other major health
problems. Other treatments might be better for you. These include heart rate control
Before trying chemical cardioversion, your healthcare provider may try to reset the
heart rate in other ways. This might include the Valsalva maneuver. This is a method
where you hold your breath and increase the pressure in your belly. This can help
slow down the heart rate down. Your healthcare provider may then use chemical cardioversion
to change your rhythm to normal. If these things don’t work, electrical cardioversion
is often the next step.
What are the risks of chemical cardioversion?
Although many people have a successful chemical cardioversion, the procedure has certain
risks. Your own risks may differ based on your age, the type of abnormal heart rhythm
you have, and your other medical conditions. Ask your healthcare provider about the
risks for you.
In rare cases, a chemical cardioversion can cause a new, more dangerous heart rhythm.
If that happens, you will get medicines or an electric shock to stop this rhythm.
Some additional risks include:
Each of the medicines used in chemical cardioversion has risks and possible side effects.
Ask your healthcare provider about the risks of the medicines you will be using.
A medicine called an anticoagulant or blood thinner may be given before and after
the procedure. This medicine helps to reduce your risk of blood clots, especially
if you have atrial fibrillation or flutter.
In some cases, the cardioversion may not restore a normal heart rhythm. Or, you might
go back to your abnormal rhythm shortly after your cardioversion.
How do I get ready for a chemical cardioversion?
Talk with your healthcare provider about what you should do to get ready for your
chemical cardioversion. Follow your healthcare provider’s instructions about what
medicines to take before the cardioversion. Don’t stop taking any medicine unless
your healthcare provider tells you to do so. You might need blood tests before the
procedure to make sure it's safe to have the procedure.
Depending on the type of irregular heart rhythm you have, you could be at a higher
risk of blood clots. Your healthcare provider may want you to take blood thinner medicine
for several weeks before and after your cardioversion. This is to help prevent blood
clots. Your healthcare provider may also want you to have a transesophageal echocardiography
test before the procedure. This test is a special kind of ultrasound. A thin, flexible
tube is put down your throat and into your esophagus. Here, the tube is close to your
heart. It lets your healthcare provider see if you have any blood clots in the chambers
of the heart.
If a clot is found, your healthcare provider may delay the cardioversion for a few
weeks. You’ll likely take blood-thinner medicine for a while until your healthcare
provider thinks your risk of clots is low. You are also likely to need blood-thinner
medicine if your abnormal rhythm has lasted more than 48 hours. This is also true
if you have had a blood clot in the past. Be sure to take this medicine exactly as
your healthcare provider tells you.
What happens during a chemical cardioversion?
The procedure will be done in a hospital for the first attempt at chemical cardioversion
so that the heart rhythm can be continuously monitored. If the first time is successful
and without complications it may then be done in a healthcare provider’s office or
in your home depending on the medicines being used. Your healthcare provider will
give you an antiarrhythmic medicine. This is given by mouth or through an IV line.
If you are treated at home, you will need careful follow-up with a cardiologist. If
you have chemical cardioversion at a hospital, someone will check your heart rate
and rhythm, and blood pressure.
The type of medicine used will vary based on your type of abnormal rhythm and your
other health problems. The following are some examples of medicines that your healthcare
provider might use:
Flecainide, dofetilide, propafenone, amiodarone or ibutilide, for AFib
Adenosine, verapamil, diltiazem, metoprolol for supraventricular tachycardia, (SVT)
What happens after a chemical cardioversion?
Sometimes chemical cardioversion works very quickly. Other times, it may take hours
to work. In rare cases, it may take up to a few days to work. In some cases, you may
need an electrical cardioversion if the chemical cardioversion did not work.
Your healthcare provider may want to check your heart rhythm for a period of time
after you have been given the medicine. Ask your healthcare provider about the possible
side effects of the medicine used in your chemical cardioversion. Be on the lookout
for these side effects. Tell a healthcare provider right away if these side effects
are severe. Call a healthcare provider right away if your symptoms get worse.
Before you agree to the test or the procedure make sure you know:
The name of the test or procedure
The reason you are having the test or procedure
What results to expect and what they mean
The risks and benefits of the test or procedure
What the possible side effects or complications are
When and where you are to have the test or procedure
Who will do the test or procedure and what that person’s qualifications are
What would happen if you did not have the test or procedure
Any alternative tests or procedures to think about
When and how you will get the results
Who to call after the test or procedure if you have questions or problems
How much you will have to pay for the test or procedure