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Home > Patients & Visitors > Health Library > Electrical Cardioversion (Defibrillation) for a Fast Heart Rate
cardioversion is a procedure in which a brief electric shock is given to the
heart to reset the heart rhythm back to its normal, regular pattern (normal sinus rhythm). The shock is given through patches
applied to the outside of the chest wall. In some situations an external defibrillator, which has paddles, might be used.
Usually, the person is sedated. If
the person is conscious, medicine is given to control pain and to cause the
person to relax to the point of being nearly unconscious during the
After cardioversion, the person's heart
rate and blood pressure are monitored.
Additional drugs to help
prevent heart rhythm problems from recurring (antiarrhythmic drugs) may also be
given before and after the procedure. If antiarrhythmic drugs are not used
after cardioversion, the heart may be at greater risk of going back into a fast
After cardioversion, you may take a blood-thinning medicine for a few weeks to prevent dangerous blood clots.
Cardioversion may be used as an emergency procedure to stop a fast heart rate that is causing low blood pressure or severe symptoms. These heart rate problems include atrial fibrillation, supraventricular tachycardia, and ventricular tachycardia.
Electrical cardioversion of the heart
is very effective. Most people who receive cardioversion return to normal sinus
rhythm immediately after the procedure.footnote 1
Risks of the procedure include the
Cardioversion is only a temporary
fix for a fast heart rate. Medicines (such as beta-blockers and calcium channel
blockers or other antiarrhythmic medicines) may be used to keep the heart rate
slow when a person has an episode of supraventricular tachycardia (SVT). For
long-term treatment and to reduce the chance of having another episode of
either SVT or ventricular tachycardia (VT), catheter ablation or medicine can
Complete the special treatment information form (PDF)(What is a PDF document?) to help you understand this treatment.
Page RL, et al. (2015). 2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia: A report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Circulation. DOI: 10.1161/CIR.0000000000000311. Accessed September 23, 2015.
ByHealthwise StaffPrimary Medical ReviewerRakesh K. Pai, MD, FACC - Cardiology, ElectrophysiologyE. Gregory Thompson, MD - Internal MedicineMartin J. Gabica, MD - Family MedicineSpecialist Medical ReviewerJohn M. Miller, MD, FACC - Cardiology, Electrophysiology
Current as ofApril 14, 2016
Current as of:
April 14, 2016
Rakesh K. Pai, MD, FACC - Cardiology, Electrophysiology & E. Gregory Thompson, MD - Internal Medicine & Martin J. Gabica, MD - Family Medicine & John M. Miller, MD, FACC - Cardiology, Electrophysiology
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