Defibrillator Implantation / Cardioversion
Cardioversion is a method to restore an abnormal heart rhythm to
normal. It can be done using an energy shock (electric
cardioversion) or medications (pharmacologic cardioversion).
Electric cardioversion may use a device that can be placed inside
or outside the body.
Learn more about Arrhythmias
External electric cardioversion uses a device called a
defibrillator. Electrode patches are placed on the front and back
of the chest and connected to the defibrillator. When the
defibrillator paddles are placed on the chest, an energy shock is
delivered to the heart. This shock interrupts all existing
electrical activity of the heart and allows the normal heart
rhythm to return.
After the external cardioversion, medicine may be given to
prevent blood clots and to help prevent the arrhythmia from
Internal cardioversion uses a device called an implantable
cardioverter defibrillator (ICD). ICDs have two parts: a pulse
generator and electrodes (wires). The generator is implanted
under the skin, like a pacemaker. The wires connect the generator
to the heart. This device also delivers an electric shock to the
heart. An implantable cardiac defibrillator is placed in people
who are at high risk of sudden cardiac death from dangerous
arrhythmias such as ventricular tachycardia and ventricular
Cardioversion can also be done by using drugs that are taken by
mouth or given intravenously. A successful cardioversion can take
several minutes to days. If pharmacologic cardioversion is done
in a hospital, the heart rate will be regularly checked.
As with electrical cardioversion, patients may be given
blood-thinning medicines to prevent blood clots from forming and
leaving the heart.
Possible complications of cardioversion are uncommon but may
- Worsening of the arrhythmia
- Blood clots that can cause a stroke or other organ damage
- Bruising, burning or pain at the site where the electrodes
- Allergic reactions to medicines used in pharmacologic
Texas Health is committed to providing quality care to heart
and vascular patients throughout North Texas and beyond. While
various technologies and services are discussed here, not all of
our hospitals offer every treatment and diagnostic technology
highlighted. Call 1-877-THR-WELL to learn more about heart and
vascular services at a Texas Health hospital near you.