Electrical Cardioversion

Electrical cardioversion uses a brief electrical shock to convert an abnormal heart rhythm into normal sinus rhythm. While electrical cardioversion does not provide a cure for atrial fibrillation, the majority of “non-emergency” cardioversions are used to treat atrial fibrillation.

In electrical cardioversion (also known as direct-current cardioversion), special electrodes or paddles are placed on the skin of the chest and back. An electrical shock is then delivered to the heart, causing the heart cells to contract simultaneously. This interrupts and terminates any abnormal electrical impulses within the heart without damaging it. The heart’s electrical system is then able to restore a normal sinus rhythm.80

 

A normal heart rhythm can be reestablished using electrical cardioversion more than 90% of the time. However, abnormal rhythms may recur within one year in about half the patients.80 The success of this treatment option is often dependent upon the type of atrial fibrillation and any existing underlying causes, such as heart disease.

In patients who have had atrial fibrillation for longer than one year, restoration of sinus rhythm is less likely. Antiarrhythmic drugs may be prescribed prior to cardioversion in an attempt to increase the odds of success and to prevent recurrent episodes of atrial fibrillation. However, the use of antiarrhythmic drugs should be considered on an individual patient basis. It is most appropriate for patients who fail to respond to direct-current cardioversion and in those who develop immediate or subacute recurrence of AF. Antiarrhythmic drug therapy is also recommended during a second cardioversion attempt, especially when early relapse has occurred. In patients who are undergoing cardioversion for an episode of atrial fibrillation lasting longer than two days, it is now common practice to also pre-administer anticoagulants to reduce the risk of stroke. 81

It is important to keep in mind that cardioversion may not be appropriate for every AF patient. There are other treatment options available for atrial fibrillation, including catheter ablation and cardiac surgical ablation. Your doctor can help you decide which treatment option is best for you.