Many people have abnormal heart rhythms (arrhythmias) that cannot be controlled with lifestyle changes or medications. Some patients cannot or do not wish to take life-long
anti-arrhythmic medications and other drugs because of side effects that interfere with their quality of life.
When medications are not an option, a non-surgical procedure called
Catheter Ablation (CA) can be used to destroy the extra pathways in the heart muscle that cause some types of abnormal heart rhythms.
The procedure involves inserting one or more flexible, thin tubes (
catheters) through small skin openings and threading them through the blood vessels and into the heart. The
electrophysiologist (a cardiologist who specializes in heart rhythm disorders) guides every movement of the catheter with real-time, moving x-rays (
fluoroscopy) displayed on a video screen. The procedure helps the doctor place the catheter at the exact site inside the heart where cells give off the electrical signals that give rise to the abnormal heart rhythm.
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Conditions Treated with Catheter Ablation
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| Normally, heartbeats are controlled by a built-in electrical system that causes the heart muscles to contract. The electrical signals that control the heartbeat begin in the heart's natural pacemaker, the sinoatrial, or SA node, which is located in the heart.s upper right chamber (atrium).
The impulse or electrical signal then spreads across both upper chambers of the heart causing them to contract at the same time and squeeze blood into the lower pumping chambers (ventricles). These impulses from the atria pass through a built-in "gate" called the atrioventricular, or AV node. The AV node controls the number of electrical impulses that travel from the atria to the ventricles.
Changes in the heart's electrical system can cause periodic episodes of an abnormal heart rhythm. Catheter ablation can prevent tachyarrhythmias (fast abnormal rhythms), which are usually supraventricular arrhythmias (abnormal rhythms that arise in the tissues above the lower chambers, or ventricles), but may also be used for ventricular arrhythmias under certain circumstances. |
| Supraventricular Tachycardias. CA is most often used to treat a rapid heartbeat that arises in the upper chambers (atria) of the heart. The major types of supraventricular tachycardia are:
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| In some instances, CA is used to treat heart rhythm disorders that originate in the heart's lower chambers (ventricles). The most common is ventricular tachycardia (VT), a dangerous arrhythmia that can lead to sudden cardiac death.Your heartbeat is regulated by a built-in electrical system that causes the heart muscles to contract. Changes in the heart's electrical system can cause periodic episodes of an abnormal heart rhythm.
Problems in the heart's electrical system that can be treated with CA include: |
| Supraventricular Arrhythmias (SVT) are heart rhythm disturbances that originate in the atria, or upper heart chambers. These include: |
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Atrial Fibrillation (AF). During atrial fibrillation, the AV node is bombarded with many rapid and chaotic electrical impulses from the atria, which cause the ventricles to beat rapidly and irregularly.In some patients, the symptoms of AF are caused by disorganized, electrical circuits (wavefronts) that wander throughout the atria. In others, it may be caused by a single, rapidly firing electrical spot (focus). This spot is commonly located in one of the pulmonary (lung) veins near where it empties blood into the left atrium. |
Three types of ablation may be performed to treat Atrial Fibrillation:
- Ablation to destroy the rapidly firing spot (focus) that is "triggering" the abnormal rhythm. The focus (or foci) is commonly located in or near the pulmonary veins in the left atrium of the heart.
- Ablation to create lines that block the abnormal electrical circuits in the atria. This may allow the heart's natural pacemaker (sinus or SA node) to regain control of the heartbeat.
- Ablation to interrupt the conduction of the electrical impulse across the AV node and prevent the abnormal impulses from reaching the ventricles. This treatment requires the implantation of a permanent pacemaker to maintain a normal heartbeat. This type of ablation procedure does not eliminate atrial fibrillation, but prevents it from causing the ventricles to beat too fast.
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| Atrial Flutter is due to an electrical impulse that travels in one large circuit in the right atrium. This impulse is funneled through a small region of heart tissue called the tricuspid isthmus, located at the bottom of the right atrium. Ablation prevents any electrical impulses from passing through this region and by interrupting the circuit prevents atrial flutter. |
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| AV Nodal Reentrant Tachycardia (AVNRT) is a heart rhythm disorder that originates in the area of the AV node. It is the third most common SVT. Some people are born with 2 pathways within their AV node.
Under the right conditions, an electrical impulse can rapidly travel around and around within the AV node going up one pathway and down the other. Ablation will eliminate one of the pathways and cure the arrhythmia. |
| AV Reentrant Tachycardia (AVRT). Some people are born with an extra connection (called an accessory pathway) between the upper and lower chambers of the heart. When the accessory pathway is visible on an electrocardiogram (ECG) it is called the Wolff-Parkinson-White Syndrome or WPW. Other people may have an accessory pathway that is not visible on an ECG. This is called a concealed, or hidden, accessory pathway. Sometimes AVRT causes an electrical impulse to travel down the normal electrical connection and then back up the accessory pathway. Ablation is used to eliminate the accessory pathway and cure the abnormal heart rhythm. |
| Atrial Tachycardia is due to an abnormal electrical impulse originating from a single spot (focus) in the atria other than in the SA node. Ablation is used to eliminate this abnormal focus. |
| Ventricular TachycardiasCA is used less often to treat ventricular tachycardias (rapid heart beats arising in the lower chambers). These types of abnormal heart rhythms are more serious than SVTs, and generally are life-threatening.
For patients at risk for sudden cardiac death (SCD), CA often is used in conjunction with ICD therapy to decrease the frequency of abnormal heart rhythms in the ventricles. It is not a substitute for an ICD (an implantable device that corrects VT before it can lead to ventricular fibrillation and cardiac arrest). |
How CA Is Performed
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| Remember, CA (catheter ablation) does not require open surgery. In the procedure, the catheter is inserted into a vein - and sometimes an artery - through a nick in the skin (usually near the groin) and guided through the blood vessels to the heart. Using x-rays to guide the procedure, the electrophysiologist (a cardiologist who specializes in heart rhythm disorders) carefully places the catheter and a burst of radiofrequency (RF) energy is sent through the tube to burn and destroy the small cluster of heart cells that are causing the arrhythmia.
RF catheter ablation is much safer than open-heart surgery, and the risk of blood loss is very low because the heat that kills diseased tissue also causes blood to coagulate. In fact, CA has been used for many years by surgeons to control bleeding during operations. For many types of arrhythmias, catheter ablation is successful in 90-98 percent of cases -- thus eliminating the need for open-heart surgeries or long-term drug therapies. |
| Radiofrequency energy is safe because it is absorbed by living tissues as simple heat, and it does not travel to do damage to healthy tissue. Regardless of the heat source, cells will die when they reach a certain temperature. Unlike radioactive energy, RF energy and the heat it generates do not alter the basic chemical structure of cells. |
Preparing for an Ablation
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| Once the decision to have an ablation is made, you will be scheduled for some routine blood work. |
Things to Remember:
- Be sure to ask your cardiologist whether or not you should stop any medications you may be taking before the procedure.
- Let your doctor know if you have any allergies to medications or x-ray dye.
- Notify the cardiologist if you are pregnant. Ablation cannot be safely performed on pregnant patients. Women who are pregnant can almost always be effectively and safely treated with other therapies until after the baby is born. Ablation can be considered at that time.
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| Before your Ablation
On the night before your ablation procedure, you cannot have anything to eat or drink after midnight. You can take your medications on the morning of the procedure with a sip of water, unless the physician or nurse has instructed you otherwise.Upon your arrival in the Electrophysiology (EP) Lab, you will be asked to change into a hospital gown and assisted onto a padded x-ray table. Your heart rate and blood pressure will be checked and you will be placed on a heart monitor. An intravenous (IV) line will be started. You will be given a mild sedative through the IV to help you relax and make you sleepy throughout the procedure. |
| During your Ablation |
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EP Lab
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A team of specialists including Electrophysiologists, one or more nurses, an EP technologist ]and a radiology technologist will perform your ablation. The members of the team will check you throughout the procedure to monitor your condition. Please do not hesitate to ask them any questions.The procedure sites (both groin areas and sometimes the right side of your neck) will be shaved and washed with an antiseptic soap. You will then be covered from your neck to your toes with a l arge sterile sheet that helps to prevent infection. The electrophysiologists will wear masks, gowns and gloves in order to maintain sterile conditions during the procedure. The lighting in the EP lab will be dimmed during most of the procedure to allow the physicians to view the heart monitors and x-ray screens more clearly. |
A local anesthetic (similar to the type you receive at the dentist) will be administered at the sites chosen for insertion of the catheters (small, thin tubes). You may feel a temporary sting or slight pressure as the area is anesthetized, in addition to some pressure as the catheters are inserted. If you experience undue discomfort, please let the physician or nurse know so they can provide you with additional medicine. Once the catheters are in position, you should feel comfortable. Before the actual ablation can be performed, the physicians must first identify the area where your abnormal rhythm is coming from. They will record the electrical activity of your heart during your abnormal rhythm to create a "map" of the precise area of heart muscle responsible.
During this time you may experience some palpitations, but otherwise you will be resting quietly. Once the physicians have identified the mechanism of your abnormal rhythm, they will insert a special catheter (the one that will deliver the RF energy). The catheter tip will be positioned against the inner surface of the heart muscle as close as possible to the site of origin of your abnormal rhythm.
Radiofrequency current is then passed into the area through the tip of the catheter in order to cauterize (burn) and silence the cells responsible for your abnormal heartbeat. If you experience any chest discomfort or pressure, be sure to inform the staff during the procedure. The length of the procedure is variable, but most commonly ranges between three to four hours. |
| After your Ablation |
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When the procedure is finished, you will be moved to a stretcher and taken to a recovery area. Under the physician's guidance, a technician will remove the catheters and apply pressure to the sites. This helps to control any bleeding that may occur. Once you are stable, you will be transferred to a regular hospital room. The nurse will check your blood pressure and heart rate, and monitor the insertion sites and pulses at regular intervals. You will be able to resume your previous diet shortly after the procedure is completed and you are considered stable. |
| An important aspect of your care following catheter ablation involves your cooperation in remaining in bed for at least four hours following the procedure. The leg or legs used for insertion of the catheters must remain straight and at rest so that the wound can heal properly. You will not be permitted to use the bathroom during this time and must therefore use a bedpan or urinal. If you have pain or notice any bleeding at the insertion sites, please call your nurse immediately.
The physician who performed your procedure will visit you later in the day to examine the insertion sites. If you have any questions regarding the procedure, please call your nurse or speak with the physician when he/she visits you. The physician may discharge you the afternoon or evening of the procedure if everything is stable. You must have someone available to drive you home and stay with you that evening. Otherwise, you will be monitored overnight and discharged the following morning. Recovery from catheter ablation is quick. After 24 hours, you should feel free to resume most of your normal activities. |
Risks & Complications
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| Most patients experience no difficulty with the ablation procedure. However, any invasive procedure that involves the heart and blood vessels has some potential risk. The most common risks include infection or bleeding. Other risks include, but are not limited to: damage to an artery or vein, formation of a blood clot which, on rare occasions, can lead to a heart attack or stroke or travel to a lung, collapsed lung or a perforation of the heart muscle or other structures.
Ablation of certain areas of the heart may cause the heart to slow too much. This may require insertion of a permanent pacemaker. The risk of needing a permanent pacemaker is in the range of 1% or less for ablation of some arrhythmias, but virtually 0% for ablation of others.
If the ablation procedure is long, the x-rays used can be irritating to the skin. The Electrophysiologist will review the risks and benefits of the ablation procedure in detail with you prior to your procedure. Please be assured that every safeguard will be provided for you before, during and after the procedure to keep the risk of any complications low. |
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