Atrial fibrillation (abbreviated as AF) is a rapid and irregular rhythm that originates from the top chambers of the heart called the atria. Treatment for atrial fibrillation includes controlling heart rate and preventing stroke as well as restoring and maintaining normal rhythm.
If you are having an ablation for another type of heart rhythm problem, such as paroxysmal supraventricular tachycardia, atrial flutter or ventricular arrhythmia, read about radiofrequency catheter ablation.
Catheter ablation is a technique in which energy in the radiowave frequency is delivered through the tip of a catheter, which heats and eliminates the “electrical short circuit” that is the cause of the AF. This procedure is called radiofrequency catheter ablation. Ohio State’s Heart and Vascular Center is a national leader in ablation procedures. Physicians at Ohio State University were the first in the country to perform an AF ablation procedure with a circular Lasso catheter in 1999, and we are one of the highest-volume AF treatment centers in the United States, with over 600 ablations performed annually. Ohio State’s electrophysiology program is the largest program in Ohio, and one of the top three in the nation, with extensive experience in managing a wide spectrum of heart rhythm problems.
Radiofrequency catheter ablation can be used to treat AF in two ways: curative radiofrequency ablation of AF and the ablate and pace method.
Curative Radiofrequency Ablation of AF
Curative radiofrequency ablation is a procedure designed to permanently eliminate AF, rather than to suppress the AF. Many times patients are motivated to have the catheter ablation procedure because they want to eliminate daily medications and/or to control their symptoms. Currently, the guidelines of the American Heart Association and the American College of Cardiology state that a catheter ablation procedure is appropriate for patients with AF who have tried and failed at least one antiarrhythmic medication.
Heart rhythm experts understand that the cause of AF often arises from electrical short circuits from inside the heart. These electrical short circuits often arise from where the pulmonary veins join the heart muscle. The pulmonary veins are blood vessels that carry blood from the lungs back to the left atrium. At this junction, many electrical short circuits may cause AF. The goal of the radiofrequency catheter ablation procedure is to ablate or eliminate the electrical misfirings from near and around the pulmonary veins and thus eliminate the AF. The goal of this radiofrequency ablation procedure is pulmonary vein isolation.
What to Expect During Catheter Ablation
Preparing for Your Procedure
In general, a few days prior to a curative radiofrequency catheter ablation procedure, patients undergo a transesophageal echocardiogram (TEE) to be certain there are no blood clots inside the heart. Understanding the anatomy of the left atrium and pulmonary veins is quite important for the ablation procedure. At Ohio State University, we utilize special imaging of the heart with a CT or MRI scan and create a 3-dimensional picture of the heart and the surrounding structures. This 3-dimensional image is downloaded into the special computer in the electrophysiology laboratory and is used as a roadmap to guide where radiofrequency ablation lesions should be placed.
You will be given specific instructions regarding when to stop, or in some cases continue, antiarrhythmic medications and/or coumadin/warfarin. You may be instructed to take an anticoagulant (anti-clotting medication) called lovenox for a brief period of time before and after your ablation procedure. You will be asked not to eat or drink anything after midnight the evening before your procedure. Please take any medications with a small amount of water. Please tell your doctor if you are diabetic and on medication. Do not smoke or use tobacco products for 24 hours before your procedure.
During Your Procedure
On the day of the procedure, you will arrive at Ohio State’s Ross Heart Hospital. You will register and undergo preparation for the procedure. You will then be moved into the electrophysiology laboratory where the computer recording and mapping equipment will be connected. The electrophysiologist will then place catheters, thin flexible wires, through your leg vein(s). The first step of the procedure is to position the catheters inside the right atria (top right chamber of the heart). The next step is to enter into the left atrium by passing a small needle through the wall separating the right and left atria. This needle is guided to the proper position by direct visualization through the use of an intracardiac ultrasound catheter. The ultrasound image provides continuous pictures of the beating heart.
Once the puncture is completed, the ablation and mapping catheters are positioned in the left atrium. The first task is then to map and create a computer model of the left atrium and the pulmonary veins. This virtual model is then compared to an actual 3-dimensional model that was created from the CT/MRI scan completed before your procedure. This 3-dimensional image has already been entered into the electrophysiology laboratory computer and is available to assist the electrophysiologist. Understanding the anatomy of the left atrium is important since the sites where radiofrequency ablation is performed is based, in part, on the anatomy.
After defining the anatomy, your electrophysiologist will begin the ablation lesions. The goal of ablation is to eliminate all the electrical short circuits around each pulmonary vein in the left atrium. This is called pulmonary vein isolation. There are several techniques that can be used to complete the ablation lesions. These include use of the Stereotaxis magnetic navigation system or use of advanced ablation technology such as an irrigated cooled-tip catheter, cryo-ablation (that freezes the tissue) or pulsed delivery of radiofrequency energy. Often, other tools will be utilized such as steerable sheaths, multipolar mapping catheters, and 3D mapping systems with CARTO and NavX. The electrophysiologists at Ohio State University have extensive experience with various advanced ablation and mapping technologies. Many times, your electrophysiologist will incorporate several different technologies to achieve elimination of the electrical connections around the pulmonary veins.
Further ablation may be required in the right atrium, either in the superior vena cava or perhaps in an area that is involved in causing another heart arrhythmia, atrial flutter. Once the ablation lesions are completed, the electrophysiologist will test the function of the electrical system of the heart and will test if AF can be provoked.
After Your Procedure
At the end of the procedure, you will be admitted to the specialized electrophysiology floor, the seventh floor of the Ross Heart Hospital (7 Ross). The staff on this floor are dedicated to management of arrhythmias and are quite familiar with taking care of patients after an AF ablation procedure. All your care during this hospitalization will be directed by a heart rhythm specialist (called an electrophysiologist).
When you are discharged, you will likely be prescribed an anticoagulant called lovenox until your coumadin level (INR) is adequate. You will also be prescribed an aspirin a day. Other drugs that may be prescribed are nexium or an antiarrhythmic medication.
After Discharge from the Hospital:
After the ablation procedure, you are asked not to perform any physical activity other than walking, climbing steps or lifting greater than 15 pounds for approximately 10-14 days. We ask you not to drive for 48 hours after the procedure. Most individuals can return to work with these restrictions within 3-5 days.
The outcome of your ablation procedure may not be known for approximately 6 – 8 weeks. Episodes of AF that may occur within this period of time do not necessarily indicate that the procedure was unsuccessful. To guard against AF during this period of time, many individuals are prescribed an antiarrhythmic medication, which is later stopped. After the antiarrhythmic medication is stopped, you will be asked to wear a cardiac event monitor for 30 days beginning about two months after the procedure. With this monitor, the heart rhythm will be recorded if you have symptoms and push the button on the monitor; or it will record an arrhythmia even if you are not aware of the heart rhythm problem and have no symptoms. You will then be evaluated in the Ohio State Arrhythmia Clinic about three months after your procedure. A 30-day cardiac event monitor and a clinic visit to the Arrhythmia Clinic are repeated at about six and 12 months after the procedure.
Possible complications related to curative catheter ablation of AF include injury to the blood vessels where the catheters are inserted into the leg vein, injury to the heart muscle where blood can leak into the sac around the heart (called pericardial effusion or pericardial tamponade). If this fluid accumulates, sometimes a needle is required to be placed into the pericardial sac to drain the fluid. Other possible complications include a risk for stroke, narrowing of the pulmonary veins, injury to the esophagus and death.
We have worked quite hard to monitor and to reduce our complications for the past 10 years. As a result of our efforts to continuously try to improve our procedure safety, we have reduced our complications to a low rate. No patient at the Ohio State University has experienced a complication related to damage to the esophagus and we have not had any deaths related to the AF ablation procedure.
Recurrences of Atrial Fibrillation after Catheter Ablation Procedure
The likelihood that AF is cured with the first procedure is dependent upon multiple factors (type of AF, how many years of AF, size of the atria and other medical problems that may contribute to AF). If your AF recurs after the first ablation procedure, the electrophysiologists at Ohio State University often recommend repeating the ablation procedure.
“Ablate – n – Pace”
A second way radiofrequency ablation can be used to treat AF is with the ablate-and-pace approach. With this procedure, the goal is to control the heart rate (but not to eliminate the AF) by ablating the normal electrical system of the heart, called the AV node. The AV node is the only electrical bridge that connects the atria (top chamber) and the ventricles (bottom chamber). Ablation of the AV node electrically disconnects the atria and the ventricle. After ablation of the AV node, the heart rate becomes quite slow, and a pacemaker must be inserted. In this manner, the ablation of the AV node prevents any excessive heart rates that may occur during AF; however, the bottom chamber of the heart becomes dependent on the pacemaker to generate the electrical impulses for the heart to beat. It is important to emphasize that this ablation procedure does not eliminate AF. This procedure is to manage the heart rate during episodes of AF, which is often the cause of symptoms.
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