CATHETER ABLATION (RFA)

What is it
Catheter ablation has revolutionized the management of patients with certain heart rhythm disorders. Having evolved from arrhythmia surgery, catheter ablation was initially performed using high voltage direct current (DC); however, over the last decade, radiofrequency current has supplanted DC as the energy source of choice and has made catheter ablation a first-line therapy for many rhythm disorders. It is an alternative to life-long drug therapy or surgery. The procedure is done in a special room, called an electrophysiology (EP) lab, by doctors trained in the study and treatment of heart rhythms.Long, flexible wires, called catheters, are inserted into the veins of the leg, arm, and neck (and possibly into arteries in the leg) and positioned in the heart. Through these catheters, the doctor can record electrical signals that come from different parts of the heart. This is similar to an ECG, which records electrical activity from the body's surface.With, a special catheter, the area of the abnormality is located inside the heart. The catheter is placed at this area and, by delivering either electrical current or heat from radio frequency waves; the defective heart tissue is destroyed. This eliminates the source of the abnormal heart rhythm or extra pathways.A catheter ablation can take several hours and does involve some risks. However, the doctor recommending this procedure believes these risks are small compared to the potential benefit for you. Your doctor will discuss this with you and answer any questions you have.

Why is it done?
The normal heartbeat is caused by an electrical impulse, or signal, that follows a certain pathway in the heart muscle, similar to the wiring in a house. But some people have abnormal heartbeats caused by impulses that come from abnormal locations or travel through an abnormal pathway. A catheter ablation is recommended as treatment for patients with certain heart rhythm disorders. In these disorders:

• An abnormal pathway short-circuits the normal electrical system of the heart, causing a fast heartbeat.
  
• The heart can " race" from a few seconds to hours.
  
• A person can have symptoms of palpitaion, chest pounding, dizziness, light-headedness, and even fainting.
  For every normal heartbeat, an electrical signal starts in the sinus node, travels through the atria (upper chamber of the heart), then through the AV node to the ventricles (lower chambers). If an electrical signal starts in a different location, it will travel an abnormal, or accessory pathway.

How is it done?
Electrophysiologic studies and catheter ablation procedures are typically performed using conscious sedation.

. Electrodes will be placed on patients' chest to monitor heart.
· The areas where the catheters are to be inserted will be shaved and scrubbed with an antiseptic solution
.· Catheters will be inserted into veins in neck, arm, and groin (and possibly into arteries in your groin) and threaded into heart under x-ray guidance.
· After positioning the catheters in different areas of your heart, the doctors will try to start your abnormal heart rhythm. This helps them find the exact area of the defective heart tissue (where the abnormal rhythm comers from)
· The special catheter is applied to the targeted area of the heart to destroy the defective tissue.

Catheter ablation sends radio waves (focused heat) to specific areas of the heart through the catheter inserted in the groin. The radio waves create an electrical current at the tip of the catheter. As the catheter is being inserted, a second electrode is placed under the skin. When the catheter is energized, the body take the energy from the tip of the catheter, to the heart and to the electrode on the skin's surface, which completes the electrical circuit. A large amount of heat is given off despite the fact that not a lot of electricity is created. The heat is taken in by the heart, which causes a small burn and destroys the part of the heart that is touched by the tip of the catheter. This destruction will deaden the nerve cells that cause the irregular heartbeat. This will usually cause the resetting of the irregular heartbeat to a regular one. Ablation can be done by radiofrequency energy or electrical current. The doctors will then try repeatedly to initiate the abnormal rhythm, to check the effectiveness of the procedure.

The catheter ablation will usually last two to four hours. When it is finished, the catheters will be removed and pressure will be applied to these areas to prevent bleeding. Pressure bandages will be kept on these areas for about 12 hours.

Before ... Precautions & prerequisites
Since most patients are scheduled for elective catheter ablation, they typically report to the hospital in the fasting state early in the morning of the procedure. Because of the potential need for systemic anticoagulation during procedures that require left heart access, the timing of the procedure with respect to menses should be considered in premenopausal women. In most patients, all AV nodal blocking agents, including beta blockers, calcium blockers, digoxin, and antiarrhythmic drugs are discontinued several days prior to the scheduled procedure. In a patient with a history of coronary artery disease, beta blockers should be gradually tapered and discontinued.You will be admitted to the hospital the day before, or the morning of your procedure. You may have several blood tests, X-rays, and an ECG (electrocardiogram). Your heart rhythm may be monitored all the time while you are in the hospital.You will be asked not to eat or drink anything for several hours, before the procedure. You may, take sips of water with medications prescribed by the doctor. Following preparation is required:

· A thorough history and physical examination
· Examination of the ECG at baseline and during tachycardia
; this is helpful for planning the procedue
· Event monitoring, which is typically more useful than Holter monitoring in documenting the tachycardia
· An echocardiogram, which is helpful in assessing the possibility of structural heart disease
· Exercise testing, which may be useful if there is a history of exercise induced arrhythmia, but is otherwise not routinely indicated
· Other studies, including radionuclide scintigraphy, cardiac catheterization, and coronary angiography, which are performed only if indicated by the patient's clinical presentation and symptoms; a serum thyrotropin (TSH) concentration to exclude hyperthyroidism is reasonable although of low yield


After
Patients are usually monitored in the recovery room for about two hours. Heart rate, blood pressure, and dressings will be checked often by the nurse. Nurse should be informed right away if there is any bleeding or discomfort. One has to lie flat in bed for about six hours. Please keep your leg and arm straight to prevent bleeding. The nurses or your family can help you with meals during this time. Patients are usually discharged the next day. While at home, doctor should be informed if

• One notices redness, swelling , or pain at the catheter sites.
• Feel palpitations, dizziness, shortness of breath, any other symptoms familiar to patient that he/she used to have earlier.·
• Develop a fever