Kadlec Regional Medical Center Cardiac Electrophysiology

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1 Definition of electrophysiology study and ablation Kadlec Regional Medical Center Cardiac Electrophysiology Electrophysiology Study and Ablation An electrophysiology, or EP, study is a test of the heart s electrical system. Normally, electricity flows throughout the heart in a regular and organized pattern. The electrical impulses bring about heart muscle contractions. Problems with the electrical system of the heart can lead to irregular rhythms, or arrhythmias, or other heart rhythm disturbances. The EP study is designed to fully test the electrical system of the heart in order to guide treatment and determine risk. The procedure involves inserting a catheter a narrow, flexible tube attached to electricity-monitoring electrodes, into a blood vessel, often through a site in the groin or neck, and winding the catheter wire up into the heart. The journey from entry point to heart muscle is navigated by images created by a fluoroscope, an x-ray-like machine that provides continuous, live images of the catheter and heart muscle. Once the catheter reaches the heart, electrodes at its tip gather data and a variety of electrical measurements are made. These data pinpoint the location of the faulty electrical site. During this electrical mapping, the doctor may instigate, through pacing (the use of tiny electrical impulses), some of the very arrhythmias that are the crux of the problem. The events are safe, given the range of experts and resources close at hand and are necessary to ensure the precise location of the problematic tissue. An ablation is a procedure that primarily treats rhythm disorders. After an arrhythmia is diagnosed during an EP study, the best treatment course may be an ablation. An ablation targets the area of abnormal electrical conduction or impulses and essentially destroys, or ablates, these areas bringing about a potential cure of the arrhythmia or rhythm disturbance. An ablation involves the application of energy to the heart tissue to destroy the electrical properties of the area in a very precise manner. There are different types of energy that may be used: Radiofrequency (RF) energy essentially heats or cauterizes the tissue of interest Cryothermal energy cools or freezes the target area Each of the different types of energy has its pros and cons and is more appropriate than the other in certain clinical situations. Why you need an electrophysiology study and possible ablation An EP study provides information that is key to diagnosing and treating arrhythmias. Information obtained from an EP study can not always be obtained from other noninvasive tests such as an EKG, echocardiogram, Holter monitor, or stress test. Although it is more invasive and involves provoking arrhythmias, the test provides data that makes it possible to: Diagnose the source of arrhythmia symptoms Evaluate the effectiveness of certain medications in controlling the heart rhythm disorder Predict the risk of a future cardiac event, such as sudden cardiac death Assess the need for an implantable device (a pacemaker or ICD) or treatment procedure such as ablation Page 1 of 5

2 An ablation is a treatment for a rhythm disturbance or arrhythmia. It offers a chance at curing the rhythm problem sometimes without the need for further medications. The type of ablation depends on the results of the EP study. The more common arrhythmias and their treatments are: Atrioventricular Nodal Tachycardia (AVNRT) This is the most common of the fast rhythms originating from the top chambers, or atria, of the heart. AVNRT involves an extra electrical connection into the main conducting wire into the heart. At times an extra beat may enter the extra connection and cause a short circuit of the main conduction. This results in the electricity spinning between the extra wire and the main conducting cable causing the bottom chambers, or ventricles, to beat rapidly. This is best treated with RF or cryothermal ablation with a cure rate of > 95%. Atrioventricular Reciprocating Tachycardia (AVRT) AVRT is caused by an abnormal electrical connection between the atria and ventricles that was present from birth. This abnormal connection bypasses the normal conduction cable and similar to AVNRT can at times short circuit causing a fast heart beat. These extra connections are called bypass tracts and can be on the right or left sides of the heart with the left-sided tracts being more common. Depending on the location and type of bypass tract, these rhythm disturbances are often best treated with RF or cryothermal ablation and carry a cure rate ranging from 70 95%. Atrial Tachycardia (AT) AT is an abnormal rhythm arising from the atria. A focal spot or spots in the atria occasionally fire an electrical impulse on their own and can lead to a fast heart rhythm. These rhythms are often treated with medication and possible ablation. Atrial Flutter Atrial flutter is essentially a short circuit of conduction within the atria. The most common form involves a large circuit in the right atrium. The electricity spins around the chamber and delivers impulses to the main conducting wire at a faster rate. The main conducting wire tries to slow the conduction to the ventricles but can only slow it so much. This is the reason this arrhythmia can cause irregular and fast heart rates. Atrial flutter is often treated with RF ablation with a cure rate > 95%. Ventricular Tachycardia (VT) VT is a rhythm disturbance of the ventricles often in the setting of abnormal heart muscle function. An EP study can be used to determine the risk of VT and sudden death and aid in the decision regarding an implantable cardioverter defibrillator. VT can be treated with medication, an ICD, or RF ablation. Atrioventricular Node (His Bundle) Ablation Ablation can also be used to purposefully disrupt the electrical connection between the top and bottom chambers of the heart. In atrial fibrillation the top chambers deliver impulses to the main conducting wire at a fast rate which in turn causes the bottom chambers to beat quickly and irregularly. By ablating or destroying the main conducting wire, the ventricles can no longer race in response to the atrial fibrillation. Therefore, an AV Node ablation is always coupled with implantation of a permanent pacemaker in order to provide a steady heart rate after the ablation. Atrial Fibrillation (AF) AF is a disorganized rhythm of the atria causing an irregular and often fast heart rhythm as noted above. AF is often found during an EP study. Treatments of atrial fibrillation include rhythm medication, blood thinners, cardioversion, and possibly ablation. An atrial fibrillation ablation is discussed on a separate information sheet and is not usually performed at the time of initial diagnosis. Page 2 of 5

3 The risks of an electrophysiology study and ablation Complications from an EP study and ablation are rare and include: Bleeding and infection at the procedure sites (< 1%) Skin burns (< 1%) Poking a hole in the blood vessels or heart (called a perforation) with possible bleeding into the sac around the heart (called effusion with possible tamponade) or into the chest cavity. These complications may require open heart surgery to repair. (< 1%) Poking a hole in the lining of the lung (called a pneumothorax). This may require a small tube to be placed into the chest to expand the lung while the lining heals over 2-3 days. (< 1%) Heart attack, stroke, and death (< 1%) Damage to the normal conduction system requiring a pacemaker (< 1%) Additional procedures often performed with an EP study or ablation Ventricular Stimulation Attempting to induce VT or ventricular fibrillation in order to determine the risk of sudden cardiac death. This procedure is very safe in the EP lab. If an abnormal rhythm is induced the heart may need to be cardioverted or shocked out of the rhythm. This is not performed while the patient is aware of his or her surroundings. Electroanatomical (3D) Mapping Some ablations require sophisticated electrical mapping systems to pinpoint the location of the rhythm disturbance. The mapping systems involve the use of special skin patches and catheters. Transseptal Puncture Occasionally abnormal rhythms originate from the left side of the heart. In order to access the left atrium from the venous circulation, a small needle is used to puncture the wall between the right and left atrium and a catheter is then inserted through this opening. Intravenous blood thinners are given to prevent clots from forming while on the left side of the heart. A small ultrasound catheter is placed into the heart through the vein in order to monitor the puncture procedure. This is called an intracardiac echocardiogram. Arterial Access In order to access the left ventricle for special electrical studies and ablations, it is often necessary to puncture an artery in the groin or arm to pass a catheter up the aorta and into the left ventricle. Intravenous blood thinners are given like in a transseptal puncture. Cardioversion As mentioned above, electrical shocks are occasionally needed to restore the normal heart rhythm. To prepare: Blood tests may be ordered by your doctor in preparation for the procedure. Ask your doctor what medications you are allowed to take. Your doctor may ask you to stop certain medications one to five days before your procedure (such as aspirin, blood thinners, or rhythm medications). If you are diabetic, ask your doctor how you should adjust your diabetic medications. Bring a list of all medications with you. Do not eat or drink anything after midnight the evening before your procedure. If you must take medications, drink only with a sip of water. When you come to the hospital, wear comfortable clothes. You will change into a hospital gown for the procedure. Leave all jewelry or valuables at home. You may need to stay in the hospital at least overnight depending on the procedure. Bring items with you (such as a robe, slippers, and toothbrush) that may make your stay more comfortable. When you are able to return home, arrange for a companion to bring you home. What to expect: Page 3 of 5

4 You will be given a hospital gown to wear. You will lie on a bed and the nurse will start an intravenous (IV) line in your arm so that medications and fluids can be administered during the procedure. You may meet with a member of the Anesthesia Department who will provide conscious sedation during the procedure if needed. Both groins will be shaved and cleansed with an antiseptic solution. Sterile drapes are used to cover you from your neck to your feet to prevent infection. It is important that you keep your arms and hands down at your sides and not disturb the drapes. To remind you, some type of restraint may be used to prevent your hands from coming in contact with the sterile field. The nurse will connect you to several monitors. You may feel nervous. You will be given a medication through your IV that will make you sleep throughout most of the procedure. Your doctor and nurse will be with you throughout the procedure. If you are uncomfortable or need anything during the procedure, let your nurse know. The procedure will usually be performed from the groin. The doctor will numb the site. Small catheters will be inserted into the veins and/or arteries of one or both upper legs depending on the planned procedure. Occasionally access is obtained through a blood vessel in the neck or arm. The EP procedure will then be performed during which time you may note a fast or irregular heart beat. Inform the doctor or staff if you feel any of the symptoms you may have experienced in the past. Upon completion of the EP procedure, the doctor may decide to proceed with an ablation or device implantation. The decision will depend on the results of the EP study and any previous plans or discussions. An EP study can take 1-2 hours to perform. An ablation or device implant can take an additional 1-2 hours. After the procedure: When the procedure is completed the catheters will be removed provided the blood is not thinned from IV medications that may have been needed. Once the catheters are removed it is important to keep the access sites immobilized for 4-6 hours. You may be admitted to the hospital at least overnight. You will be placed on a special monitor called telemetry that allows your heart rhythm to be displayed on monitors in the nursing unit. If you had new leads and a pacemaker implanted, you will also have a Holter monitor to record your heart rhythm for several hours. This is another way to check proper pacemaker function. The morning after your procedure you may have a chest x-ray to check your lungs and the position of any new leads that may have been implanted. Page 4 of 5

5 Before you leave the hospital, your doctor and nurse will talk to you about activity, medications or any follow-up appointments. Do not drive for 48 hours after an EP study and/or ablation. Do not lift anything greater than 10 pounds for 1 week. Keep the puncture sites clean and dry for 48 hours. Use an occlusive dressing while bathing or showering during this time. If a new device was placed, please see the device information sheets for additional instructions and restrictions. Patient signature Date Physician signature Date Page 5 of 5