Atrial Fibrillation (cont.)
More Atrial Fibrillation (A Fib) Medical Treatment
Cardioversion (also termed defibrillation): This technique uses electrical current to "shock" the heart back to normal sinus rhythm with an electrical current. This is sometimes called DC cardioversion. Prior to cardioversion, many patients undergo a sonogram of the heart to determine if any clots are present.
- Cardioversion is done by connecting a device called an external defibrillator to the chest with patches or paddles.
- When this is performed in a hospital, an anesthetic is usually given first so the patient is sedated and asleep during the procedure because the electrical discharge is painful.
- Cardioversion works very well; more than 90% of people convert to sinus rhythm. It is most successful if the atrial fibrillation is new (that is, hours, days, or a few weeks). For many, however, this is not a permanent solution because the arrhythmia often comes back.
- Cardioversion increases the risk of stroke and thus usually requires pretreatment with an anticoagulant medication.
Catheter ablation (radiofrequency [RF] ablation) is a technique that electrically burns/destroys some of the abnormal conduction pathways in the atria using radio waves.
- A catheter is threaded into the atria and delivers radiofrequency energy (heat), which interrupts (ablates) a portion of the abnormal electrical conduction pathway. This inactivates the abnormal pathway to provide more consistent flow of electrical impulses from the SA node. The technique is also termed radiofrequency ablation.
- In atrial fibrillation, RF ablation is currently best reserved for patients who have tried antiarrhythmic medications without success or who cannot take these medications. Current success rates are in the 60%-70% range. However, serious complications associated with the procedure can occur (for example, loss of effective electrical activity in the atria), and these need to be discussed carefully with the doctor before undergoing this procedure.
- In some patients, most of the electrical activity in the atria needs to be destroyed. Consequently, such patients require a pacemaker (see below) to make the heart's ventricles contract in a more normal manner.
- In 2011, the FDA approved AtriCure (an ablation system) for the treatment of atrial fibrillation in patients undergoing open concomitant coronary artery bypass graft (CABG) surgery and/or valve replacement or repair.
- Another technique to treat A fib is cryoablation surgery where a catheter is threaded into the atrium, placed adjacent to veins causing abnormal atrial electrical activity, and freezes the venous tissue to halt the activity.
Pacemaker: A pacemaker is an electronic device that prevents slow heartbeats and may reduce the likelihood of atrial fibrillation in a small number of patients. The artificial pacemaker takes the place of the "natural pacemaker," the SA node, supplying electrical impulses to keep the heart beating in a normal rhythm when the SA node no longer can.
- The pacemaker is usually implanted in both the right atrium and right ventricle. The goal is to override the patient's own atrial fibrillation electric impulses with a new atrial electrical pacemaker. A minority of patients are offered this technique currently. This is a more complex technique and device, and no long-term data regarding success are available yet.
- A pacemaker is occasionally used in conjunction with radiofrequency ablation of the AV node, which disconnects the atria from the ventricle so rapid heart rates cannot be conducted to the ventricles. The ablation creates complete heart block (no connection between atrial electrical activity and atrial contractions and ventricular contractions), and the ventricle contractions become dependent on the artificial electrical pacemaker in the right ventricle for synchronized and regular contractions between the atria and ventricles.
- Some machines and devices in a person's environmental surroundings can interfere with the production of electrical impulses by a pacemaker. For example, airport security devices may deactivate some pacemakers. People need to become familiar with which types of devices may have this effect on their pacemaker, and avoid those devices. The patient's doctor that places the pacemaker and the device maker should educate the person about the device use, limitations, and potential complications. Patients should not be hesitant to ask any questions they may have about the device.
- If you have a pacemaker, always carry an identification card that explains this. It may be necessary to present this identification when going through airport security and ask to be hand searched as some security machines may inactivate pacemakers. Patients should always tell any medical or dental personnel that they have a pacemaker.
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