Cardioversion is a procedure in which synchronized, low-voltage electrical impulses are administered to the heart to correct an abnormal rhythm, also called an arrhythmia. The external type of cardioversion is called electric cardioversion, and involves placing a defibrillator, a small machine with pads and electrodes, on the patient’s chest. Electrical cardioversion is performed to correct abnormal heartbeats in non-emergency (“elective”) situations.
WHEN IS IT INDICATED?
Cardioversion may be used before or after other treatment methods, and is indicated in patients who have heart conditions involving an abnormal rhythm. These conditions include:
- Atrial fibrillation;
- Atrial flutter;
- Ventricular tachycardia, an abnormally fast heartbeat of more than 100 beats per minute that originates in one of the ventricles; and
- Ventricular fibrillation, an abnormal, non-coordinated heart rhythm originating in one of the ventricles.
In most cases, patients must undergo anticoagulation — administration of anti-clotting drugs such as heparin, low-molecular weight heparin, warfarin (Coumadin), or a direct thrombin inhibitor (Xarelto Pradaxa, or Eliquis) — before cardioversion. Although the physician will provide specific pre-procedure instructions to the patients, typically patients are asked to refrain from eating or drinking within 8 hours of the cardioversion procedure. Medications should still be taken on the day before and the day of the procedure, but with only a small sip of water.
WHO IS ELIGIBLE?
Patients with an abnormal heart rhythm are eligible for cardioversion such as atrial fibrillation, or atrial flutter.
RISK FACTORS FOR POSSIBLE COMPLICATIONS
Patients who have had an arrhythmia for longer than one year and those who are not taking an anticoagulant medication before cardioversion are at greater risk for complications. Compromised kidney or liver function as well as the presence of other heart conditions such as heart failure or abnormal valves may increase risk as well.
WHAT TO EXPECT
An anesthesiologist will give the patient medication through an intravenous (IV) line to eliminate pain and induce sleep. Men may have their chest hair shaved, and electrocardiogram (ECG) patches will be placed on the chest and sometimes the back as well so that the health professionals can monitor the patient’s heartbeat during the procedure. Adhesive cardioversion pads will then be placed firmly on the chest. They will automatically discharge a specific amount of electric current (lasting a few seconds) to the heart. In most cases, this will be repeated a few times to restore a regular rhythm.
Afterward, the patient’s physician may perform another ECG to ensure the procedure was successful. Results and next steps will be discussed and the patient will be moved to a recovery area.