Cardioversions are often non-emergency, elective procedures that utilize a perfectly-timed electric shock to help a patient achieve a standard heart rhythm. In an emergency scenario, cardioversions are used to correct an irregular heartbeat (or cardiac arrhythmia, which affects about 2.2 million Americans), which often paves the way for low blood pressure, a faint feeling, chest pains and breathing challenges.
Irregular heart rhythms are caused by abnormalities in the sinus node, which is located in the heart's upper-right chamber and sends electric signals (or "pacemaker cells") through the organ, resulting in a normal heart beat.
While some patients are treated with electric cardioversion, others are able to control an increased heart rhythm through medication, which alter the heart's electrical characteristics to return it to a natural rhythm. Your doctor will advise you as to which treatment will work best for your condition.
Patients treated with external electric cardioversion will have special pads - connected to an external defibrillator -- placed on the chest and back. While the defibrillator monitors the heart's rhythm, the pads deliver the brief shock that restores the heart's normal pace. Because some patients find the shock to be uncomfortable, they receive a short-action sedative and often sleep through the procedure. If one shock doesn't achieve the goal, more shocks may be delivered.
In order to guard against heart attack or stroke brought on by a dislodged clot during the cardioversion procedure, patients who have had abnormal heart rhythms for an extended period of time usually undergo an anticoagulation protocol that begins about a month before the scheduled procedure.
The process encompasses taking medications (like aspirin or warfarin) to thin the blood, and anticoagulation can continue from four weeks to six months after the cardioversion.
Patients who have experienced heart rhythm deviation for 48 hours or less can have the cardioversion procedure without blood-thinning drugs.
If external electric cardioversion doesn't achieve the desired results, doctors will utilize internal electric cardioversion. With internal electric cardioversion, an implantable cardioverter defibrillator - which is a generator, not unlike a pacemaker - is implanted under the skin, with wires connecting the generator to the heart. The defibrillator senses unusual heart rhythms and sends a shock to the heart to restore the heart beat to normal. Implantable cardioverter defibrillators generally last between four and eight years.
Although recovery only takes a few hours, most hospitals do not allow patients who have had an external electric cardioversion drive home after the procedure. Complications are rare, but can include a heart rate that continues to race, blood clots, allergic reactions to drugs administered in chemical cardioversion, and bruising or pain on the chest and back where the paddles were utilized.
Reports have indicated that nearly 90 percent of all people who have cardioversion treatment almost immediately experience normal heart rhythms. That rate grows to nearly 95 percent for patients who take antiarrhythmic drugs before the procedure. Cardioversion can return the heart to its normal rate, but is not considered a permanent solution to abnormal cardiac rhythm.