Cardioversion is a method to restore an abnormal heart rhythm back to normal.
Cardioversion can be done using an energy shock (electric cardioversion) or medications (pharmacologic cardioversion).
Electric cardioversion may use a device that can be placed inside (internal) or outside (external) the body.
External electric cardioversion uses a device called a defibrillator.
Emergency external electric cardioversion is used to treat any abnormal heart rhythm (arrhythmia) that is life threatening, such as ventricular tachycardia or ventricular fibrillation. Such a shock can be life saving.
External electric cardioversion may also be used when there is not an emergency.
After the external cardioversion, you may be given medicine to prevent blood clots and to help prevent the arrhythmia from coming back.
An implantable cardioverter-defibrillator (ICD) is a device that is usually placed underneath the skin of your upper chest. This is a semi-permanent implantation (devices may need to be replaced after 6 - 10 years).
See also: Implantable cardiac defibrillator
CARDIOVERSION USING DRUGS (PHARMACOLOGIC)
Cardioversion can be done using drugs that are taken by mouth or given through an intravenous line (IV). It can take several minutes to days for a successful cardioversion. If pharmacologic cardioversion is done in a hospital, your heart rate will be regularly checked. Although rare, cardioversion using drugs can be done outside the hospital. However, this requires close follow-up with a cardiologist.
As with electrical cardioversion, you may be given blood thinning medicines to prevent blood clots from forming and leaving the heart (which can cause a stroke).
Possible complications of cardioversion are uncommon, but may include:
People who perform external cardioversion may be shocked if the procedure is not done correctly. This can cause heart rhythm problems, pain, and even death.
Lafuente-Lafuente C, Mahé I, Extramiana F. Management of atrial fibrillation. BMJ. 2009; 339:b5216. doi: 10.1136/bjm.b5216.
Miller JM, Zipes DP. Therapy for cardiac arrhythmias. In: Libby P, Bonow RO, Mann DL, Zipes DP. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 8th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 33.
Epstein AE, DiMarco JP, Ellenbogen KA, Estes NA 3rd, Freedman RA, Gettes LS, et al. ACC/AHA/HRS 2008 guidelines for device-based therapy of cardiac rhythm abnormalities: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the ACC/AHA/NASPE 2002 Guideline Update for Implantation of Cardiac Pacemakers and Antiarrhythmia Devices): developed in collaboration with the American Association for Thoracic Surgery and Society of Thoracic Surgeons. Circulation. 2008;117:e350-e408.