Cardioversion is a technique used to treat several kinds of abnormal heart rhythm, calledcardiac arrhythmias.
When someone needs cardioversion, they are often in a life-threatening situation.
Both electricity and drugs may be used together to give a shot to restore normal heart function.
Pixel_away / Getty Images
This article explains different kinds of heart rhythms that are treated by using cardioversion.
It also discusses what to expect during your heart rhythm treatment, along with risks and side effects.
These rhythm disruptions can have quite a few causes, from medications toelectrolyte imbalancesor even simply age.
Often, these arrhythmias are due to heart disease.
Cardioversion can be done by using methods that, in most cases, rely on either electricity or medication.
An electrical shock is given using adhesive electrode patches connected to a defibrillator.
If the person is awake, a sedation medication may be given beforehand.
Some people may need to have chest hair removed.
This is known as defibrillation or unsynchronized cardioversion.
Certain heart arrhythmias are common in the absence of any pulse.
The heart isnt able to pump any blood, so there is no pulse.
Defibrillation causes most of the heart muscle cells to contract all at the same time.
This form of cardioversion is used in the hopes of restoring a cardiac rhythm with a pulse.
A normal heart rate in most people is between 60 and 100 beats per minute.
In ventricular tachycardia cases, the rate can reach as high as 220 beats per minute.
The rapid rate and the hearts inability to pump blood make this a lethal rhythm.
Its just too fast to be effective in pumping blood out to the body.
Since youre likely to still be conscious with this rhythm, a different throw in of cardioversion is used.
The electrical impulse needs to be timed with precision so that its synchronized to the hearts rhythm.
They also can be used for long-term control of atrial fibrillation.
One advantage of using drugs instead of electricity is that sedation isnt needed in people who are alert.
The medications used for cardioversion will be specific to the condition being treated.
People whove experienced both electrical and pharmacological cardioversion usually describe the cardioversion through medication as much less uncomfortable.
Beta Blockers
Certain arrhythmias can be slowed with a class of drugs called beta blockers.
These medications help to restore a rhythm that improves blood flow and reduces symptoms.
Beta blockers may be used to achieve long-term control over rapid heart rates.
They also are used to treathypertension(high blood pressure).
For example, no one who has a pulse should be defibrillated.
There are a few common situations in which a shock is more risky than others.
Sedation also may be used after a cardioversion procedure.
This is often the case for people whose condition was too unstable to wait for sedation.
Medications used to restore stable heart rhythms are effective but may have serious risks.
This can lead to complications such as blood clots, pain, or other unintended heart rhythms.
After Cardioversion
Many people will experience significant and immediate improvement of theirsigns and symptomswhen cardioversion is successful.
The underlying cause of the heart arrhythmia then becomes the focus of treatment.
If the procedure doesnt convert the rhythm on a first attempt, there is often a second try.
In most cases, patients can receive multiple electrical shocks or doses of medication without harm.
Side Effects
Its possible to experience side effects after electrical cardioversion.
This typically lasts for a few seconds.
In some cases, the feelings can be prolonged a few seconds.
Some of these rhythms, such as atrial fibrillation,require treatmentbut are typically not life-threatening.
In other cases, the abnormal heart rhythm is lethal and cardioversion can be life-saving.
2014;64(21):e1-e76.
doi:10.1016/j.jacc.2014.03.022
American Heart Association.Ventricular fibrillation.
American Heart Association.Implantable cardioverter defibrillator (ICD).
