Tell your healthcare provider about all the medicines you take. This includes over-the-counter medicines such as ibuprofen. It also includes vitamins, herbs, and other supplements, and any recreational drug use.

You may need blood tests before the procedure. This is to make sure the procedure is safe for you. Blood tests can also help identify causes for irregular heart rhythms such as abnormal levels of electrolytes and thyroid hormone levels. A cardioversion may not be successful if there are conditions causing abnormal test results that need to be treated too. 

And you may 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. There, the tube is close to your heart. It lets your healthcare provider see if you have any blood clots. Your cardioversion will be delayed if a clot is found.

Talk with your healthcare provider how to get ready for your procedure. Follow his or her instructions about what medicines to take before the procedure. This includes medicines that prevent arrhythmias. Don’t stop taking any medicine unless your healthcare provider tells you to.

If you’re at a higher risk for blood clots, your healthcare provider may want you to take blood-thinner medicine. You may take this several weeks before and after the procedure.

Make sure to:

• Ask a family member or friend to take you home from the hospital.

• Not eat or drink after midnight the night before your procedure, unless your healthcare provider says it’s OK.

• Follow all other instructions from your healthcare provider.

You will be asked to sign a consent form that gives your permission to do the procedure. Read the form carefully. Ask questions if something is not clear.

The procedure may be done in a hospital or an outpatient facility that has continuous heart rhythm monitoring. A healthcare provider will give you medicine. It may be given through a vein in your arm or hand (IV). Or you may take it by mouth.

The type of medicine is based on your type of arrhythmia and your overall health. Examples of medicines that are used include:

• Flecainide, dofetilide, propafenone, amiodarone, or ibutilide (for atrial fibrillation or atrial flutter)

• Adenosine, verapamil, diltiazem, or metroprolol (for supraventricular tachycardia)

• Amiodarone (for ventricular tachycardia)

Your heart rate and rhythm will be monitored for a few hours to see if the conversion worked. 

Chemical cardioversion may work very quickly. Or it may take hours to work. You may need an electrical cardioversion if the medicine did not work. Your healthcare team will create a new care plan for you if this occurs.

Ask your healthcare provider about medicine side effects to watch for.

You may need to take blood thinner medicine, such as warfarin, for several weeks after the procedure. Take this exactly as directed. You may also need to take a medicine to prevent arrhythmias. Take all your medicines exactly as directed.

Follow up with your healthcare provider, as advised. 

Call your healthcare provider right away if you have any of these:

• Trouble breathing or chest pain (call 911)

• Dizziness

• Fainting

• Severe side effects from the medicine, including uncontrolled bleeding if you are on blood thinning medicines

• Worsening palpitations