Definition & Overview

The heart beats between 70 to 100 times per minute in adults and about 60 to 100 times in children when at rest. This rate is ideal in keeping the organs of the body functioning normally when a person is not exercising. If the heart is beating too fast and in irregular intervals even when at rest, the condition is called arrhythmia. If left untreated, this condition can result in serious complications.

Cardioversion is the process of forcing the heart to beat in normal rhythms by using medications or electrical devices. The process is commonly used in the treatment of atrial fibrillation, atrial flutter, atrial tachycardia, and ventricular tachycardia.

Cardioversion is usually performed in a hospital setting. Doctors will attempt to force the heart to beat normally using medications. If these fail, the doctor will deliver electrical shock to "reset" the heart. Electrical cardioversion takes around 30 minutes to complete and is performed while the patient is asleep. Patients are likely to be woken up by the shock but won't likely to remember the procedure at all.

Who should undergo and expected results

Having irregular heartbeat is normally a dangerous condition. While some may not have immediate life-threatening implications, it is likely that the condition will progress into something more serious when left untreated.

Not everybody with an irregular heartbeat will display symptoms. However, those who do display symptoms of arrhythmia usually experience fatigue and shortness of breath. Some may even faint.

If you feel that your heart is beating in an abnormal rhythm, you should schedule an appointment with your doctor even if you don't feel other symptoms. Leaving the condition untreated may result in a variety of complications, such as the formation of blood clots, which prevents the normal flow of blood through the heart, which would then result in organs of the body not receiving enough oxygen-rich blood.

How the procedure works

If doctors determine that you have an abnormal heart rhythm, they will attempt to restore normal heartbeat through cardioversion with medications, also called pharmacologic or chemical cardioversion.

For some people, medications are enough to treat the condition. Unfortunately, for some cases, electrical cardioversion will be required. Prior to electrical cardioversion, patients are put to sleep using a sedative so they will not feel any pain or even discomfort during the procedure.

The doctor will then deliver an electrical shock to the heart using two paddles placed on the chest. In some cases, one paddle is placed on the chest and the other on the back. An electrical shock is delivered through the paddles, which will last less than a second.

The shock will stop the heart for a brief moment so that it restarts. Some patients only need one shock to restore a normal heartbeat, but others may need more.

The shock will normally force the person to wake up, but they usually won't remember the shock when they do. It may take a few more minutes before the heartbeat returns to normal.

Possible risks and complications

Although cardioversion, especially electrical cardioversion, is one of the best ways to restore normal heart rhythm, it may result in a variety of complications. For instance, if an abnormal heart rhythm has been going on for some time, it's likely that a blood clot may have already formed in the heart's left atrium. Electrical cardioversion may dislodge the clot, which would then travel to the brain and cause a stroke.

To prevent this from happening, the doctor will prescribe medications at least two to three weeks prior to the procedure. The medicine will prevent blood clots from forming. Additionally, the doctor may need to perform a procedure called transesophageal echocardiography (TEE) to see if a blood clot has formed prior to performing electrical cardioversion.

Electrical shocks delivered to the body will cause a bit of skin irritation. This is a normal result of electrical cardioversion, so the doctor will give you topical creams to manage the condition.

While cardioversion is an effective way to normalize heart rhythms, it is not always effective. If the procedure fails to normalize a patient's heart rhythm, other forms of treatment, such as an implantable cardioverter defibrillator (ICD) or certain types of medications will be used.

References:

  • Epstein AE, DiMarco JP, Ellenbogen KA, et al. 2012 ACCF/AHA/HRS focused update incorporated into the ACCF/AHA/HRS 2008 guidelines for device-based therapy of cardiac rhythm abnormalities: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines and the Heart Rhythm Society. J Am Coll Cardiol. 2013 Jan 22;61(3):e6-75.

  • Lafuente-Lafuente C, Mah 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: Bonow RO, Mann DL, Zipes DP, Libby P. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 9th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 37.

  • Morady F. Electrophysiologic interventional procedures and surgery. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 66.

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