What is an EP Study?

An EP Study is a recording of the electrical activity your heart. This test is used to help your doctor find out the cause of your rhythm disturbance and the best treatment for you. During the test, your doctor may safely reproduce your arrhythmia, and find where it is coming from. If possible, the arrhythmia will be cured with an ablation. Otherwise, medications or a device (Pacemaker or ICD) will be used to control it.

What is an EP study used for?

• Determine the cause of an abnormal heart rhythm
• Locate the site of origin of an abnormal heart rhythm
• Decide the best treatment for an abnormal heart rhythm

What can I Expect?

• Your doctor may ask you to stop certain medications one to five days before your test (such as aspirin products). If you are diabetic, ask your doctor how you should adjust your diabetic medications.
• Do not eat or drink anything after midnight the evening before your test. If you must take medications, drink only a sip of water.
• When you come to the hospital, wear comfortable clothes. You will change into a hospital gown for the procedure.
• Your doctor will tell you if you can go home or must stay in the hospital. If you are able to go home, bring a companion to drive you home.
• You will lie on a bed and the nurse will start an intravenous (IV) line into your arm or hand. This is so you may receive medications and fluids during the procedure. You will be given a medication through your IV to relax you and make you drowsy, but it will not put you to sleep. The nurse will connect you to several monitors.
• Your groin will be shaved and cleansed with an antiseptic solution. Sterile drapes are used to cover you, from your neck to your feet. A strap will be placed across your waist and arms to prevent your hands from coming in contact with the sterile field.
• The doctor will numb your groin with a special medication and then insert 2 or 3 IV’s into the vein in your groin. Guided by an x-ray machine, the catheters are threaded through the IV’s to your heart. The catheters sense the electrical activity in your heart and are used to evaluate your heart’s electrical system.

Example of distal end of an electrode catheter. Catheters are about 50" long and the electrodes are located near the tip (shown here). These electrodes come in contact with the patient's heart tissue. Some catheters have a fixed curve; others have a capability for producing a variable curve using a hand-held controlling device (not shown). During an EP study, electrode catheters may be positioned in multiple locations in the heart (right panel). However, usually they are positioned in 1) the right atrium, 2) the AV node and His bundle region at the junction between the right atrium and right ventricle, 3) the right ventricular apex and, 4) the coronary sinus and great cardiac vein. The coronary sinus catheter is generally only used in patients with certain types of supraventricular tachycardia. After the completion of the procedure all the catheters are removed sense the electrical activity in your heart and are used to evaluate your heart’s conduction system.

• The doctor will use an external pacemaker to give the heart electrical impulses through one of the catheters to increase your heart rate. You may feel your heart beating faster or stronger.
• Your nurses and doctor will want to know about any symptoms you are feeling. If your arrhythmia occurs, your doctor may give you medications through your IV to test their effectiveness in controlling it. If necessary, a small amount of energy may be delivered by the patches on your chest to bring back a normal heart rhythm.
• The EP study takes about one to two hours to perform.

After the Study:

• The doctor will remove the catheters from your groin and apply pressure to the site, to prevent bleeding. You will be on bedrest for about 4 hours.
• A sterile dressing will be placed on the site to protect it from infection. The nurse will check your bandage regularly, but call your nurse if you think you are bleeding (have a wet, warm sensation) or if your toes begin to tingle or feel numb.