What do I need to know about electrocardioversion?
Using Electrical Cardioversion for AFib
“Electrical cardioversion” is a process that shocks the heart to convert it from an irregular pumping rhythm back into a normal sinus rhythm.
The EKG illustration shows what the heart rhythm looks like before and after cardioversion.
When is Electrical Cardioversion Considered an Option?
Patients who have recently begun to have atrial fibrillation that isn’t stopping on its own (known as persistent atrial fibrillation) may be encouraged to try electrical cardioversion early in the process to stop the AFib and put the heart back into normal sinus rhythm.
For other AFib patients, electrical cardioversion may not be tried until later, when medication has stopped working.
While electrical cardioversion may be effective at converting the heart back into normal sinus rhythm, most people with persistent or recurring AFib will find that a cardioversion procedure is only a temporary solution for the sinus rhythm problem.
What to Expect From Electrical Cardioversion
Preparation for the Procedure
Clot Prevention: First, to avoid having blood clots break free during this procedure, you may take anticoagulants (warfarin, Coumadin®, or one of the NOAC -non-VKA oral anticoagulants) for three to four weeks before the procedure to eliminate your risk of blood clots.
Possible Visual Inspection: If you can't take anticoagulants, you may have a transesophogeal echocardiogram (TEE) in which you are sedated so a narrow tube containing an ultrasound imaging device can be inserted into your throat to ensure there are no existing blood clots in your heart. Sometimes the view taken from your esophagus provides the best look at the heart chambers.Mostly likely your doctor will tell you not to have anything by mouth after midnight the night before the procedure.
Sedation for The Procedure: You will have your electrical cardioversion in the electrophysiology (EP) lab or suite. Once you arrive, you will be fitted with an IV for receiving medications and fluids and connected to monitors so the doctor can see what is happening with you. When it's time for the procedure to begin, you'll be given a medication intravenously to put you to sleep.
Use of External Paddles: Once you're asleep, the doctor will use the defibrillator / cardioverter / pacemaker machine to give your heart a jolt of energy that will be delivered through paddles or EKG-type patches placed on the front and back of the chest. This electric shock should restore your normal heart rhythm, and may be repeated several times during a single procedure.
Internal Leads: If external cardioversion fails, then internal cardioversion may be done and involves delivering the jolt of energy through catheters inside the heart.
Recovery and Release or Discharge: Once you wake up following the electrical cardioversion, you can go home, but will need to have someone drive you. For a few days following the procedure, you may find that your chest is tender or your skin may have red patches.
After the electrical cardioversion, you may be on an antiarrhythmic drug, a rhythm control medication that should keep the heart in normal sinus rhythm. You will also remain on an anticoagulant, such as warfarin, Coumadin®, or the newer oral anticoagulants available to prevent blood clots.
Risks from Electrical Cardioversion
Electrical cardioversion risks include:
- skin burns
- fluid in the lungs
- heart attack, stroke, or - as with most procedures - death
Success Rates for Electrical Cardioversion
Procedural Success: Various studies have reported that electrical cardioversion is over 90 percent effective in helping people return to a normal sinus rhythm during the procedure. However, many people revert back into AFib shortly thereafter. Success has been shown to be enhanced when patients are on an antiarrhythmic drug beforehand, which helps prevent reverting back to AFib.
Long-term Rhythm Maintenance Success: Continued success can depend on the size of the left atrium as well as how long the patient has been in AFib. Patients who have a very large left atrium (one greater than 5 cm) or those who have been in constant AFib for a year or two, may find that electrical cardioversion is not effective in either converting to or maintaining a normal sinus rhythm.
Although rhythm maintenance is not the only concern to be addressed for people with AFib, it is a significant one. It may also be important to note that getting back into a normal sinus rhythm may not affect your stroke risks.
Following a successful electrical cardioversion, only about 20–30 percent of patients who are not taking additional rhythm controlling medications will continue to maintain normal sinus rhythm throughout the first year. The overall likelihood of reverting back into atrial fibrillation is also quite high for those who are taking rhythm control drugs.
Outcomes for People with Sleep Apnea: We know that AFib patients with untreated sleep apnea are more likely to revert back into AFib after electrical cardioversion than AFb patients without sleep apnea. The possibility of sleep apnea might be something to investigate if you have had unsuccessful cardioversions.
What’s Next? When neither medication nor electrical cardioversion yields long-term success, then catheter ablation or surgical ablation may be next for consideration in an attempt to manage and cure your AFib.