An Electrophysiology Study (EPS) from Allen Hospital in Waterloo, IA

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Electrophysiology Study (EPS)

Why is the doctor performing this test?

To locate the source of an abnormal heart rhythm (arrhythmia), to determine its cause, and to determine the best way to treat the arrhythmia. Some symptoms associated with arrhythmia are palpitations, dizziness or fainting spells. Arrhythmias are usually a byproduct of damage to the heart from disease or age. People with otherwise healthy hearts can develop an arrhythmia, but it is rare.

How do I prepare for the test?

  • Do not eat anything after midnight the night before the test. No food in your system for at least 8 hours before the procedure.
  • Discuss current medications you are taking with your physician prior to the test.
  • Mention any allergies to your physician.
  • Make arrangements to have a family member or friend take you home following the procedure.
  • Bring a list of your current medications to the physician (including aspirin or blood thinners). Your doctor may want to continue them while you recover from the procedure.

NOTE: Your doctor may decide to keep you overnight in the hospital. Pack a small, overnight bag with pajamas, toiletries, etc. We recommend including something to pass the time, like a book or magazines.

What is the test?

The heart's rhythm (or "beat cycle" or "contraction cycle") is controlled by a natural pacemaker called the sino-atrial node (SA node). The SA node, located in the right atrium, creates an electrical impulse that travels first through the right and left atria, and then to the right and left ventricles, causing the heart to beat. Sometimes, abnormal electrical impulses occur in the heart, causing an abnormal rhythm called an arrhythmia. Arrhythmias can be too slow (Bradycardia), too fast (Tachycardia), or irregular. During the Electrophysiology study, catheters are inserted into blood vessels in various locations, and advanced to the heart. Through these wires, electrical impulses are both delivered to and received from the heart assessing both normal and abnormal conditions. An attempt is made to duplicate the patient's clinical arrhythmia by pacing the heart from different locations and at different rates. Once an arrhythmia has been initiated it is assessed and analyzed to determine its origin and pathway of conduction. Once determined, a decision is made on best cause of treatment, which may include medications, ablation with radiofrequency, or even device treatment where a Pacemaker or an Implantable Cardiac Defibrillator (ICD) may be implanted. At the end of the procedure the catheters are removed and pressure is placed on the puncture site to prevent bleeding.

Who gets arrhythmias?

Arrhythmias are usually a byproduct of damage to the heart from disease or age. People with otherwise healthy hearts can develop an arrhythmia, but it is rare. Many things can damage your heart's electrical system and lead to an electrical problem: diseases of the heart valves, enlargement of the heart, coronary artery disease, high blood pressure, lung disease, congenital heart problems (existing at birth) and scarring from a heart attack.

What happens during an Electrophysiology Study?

The Electrophysiology Study may be done as an inpatient or in many cases, as an outpatient. If you are an outpatient, arrive 2 hours before your procedure. After you go through admitting, you will go to the third floor (3 South) - Outpatient Care - unless other arrangements have been made. You will change into a hospital gown. An intravenous line (IV) will be started in a vein in your arm and you will be given medication to help you relax. You will be transported to the EP laboratory located on the second floor cardiology unit. You will arrive to the laboratory 30 to 60 minutes before your procedure. Sometimes a scheduled procedure time must be changed due to emergencies.

Once in the EP lab, you will be transferred to a table. Electrodes (sticky patches) will be placed on your chest, back, arms, and legs. You may need to be shaved so the electrodes will stick. You will also be hooked up to other monitoring devices such as a blood pressure cuff and oxygen monitor. You will need to lie still and relax during the test because movement or muscle tensing can interfere with the electrical signals.

The area where the catheters are to be placed (in the groin, arms or neck) will be cleansed with an antiseptic solution. Sterile towels and sheets will be placed over you, leaving exposed only the area where the catheters will be inserted. The doctor will inject a numbing medicine in the areas where the catheters will be inserted. You will feel some stinging at that time. Once the medication takes effect, you should not feel any discomfort.

Once the areas are numb, one to four special insulated wires (called catheters) are inserted into different parts of your heart using a special x-ray machine. This machine allows the doctor to watch the catheters as they move into the correct places. Part of the x-ray machine will be placed directly over your entire body. You will receive only intermittent low dose x-rays.

After the catheters are in position, the doctor evaluates your heart rhythm disturbance by giving your heart small electrical impulses by an artificial pacemaker through one of the catheters. This will make your heart beat at different rates. You may feel your heart beating quickly, or experience fluttering or palpitations. If you feel chest pain or discomfort, let the doctor know.

You may be asked questions during the test such as:
"Do you feel faint?"
"Do you feel your heart pounding?"
"Is this feeling similar to one you have had before?"
"Do you feel dizzy or lightheaded?"
"Are you short of breath?"
"Do you have chest pain or pressure?"

Some patients pass out when the doctor is inducing a rapid heart rhythm. If you do pass out, it will be for a very short period of time. A small electrical shock may be required to bring back your normal heart rhythm. Most patients report that they do not experience any pain. Some patients do not even realize they have passed out.

If you do have an irregular rhythm, the doctor may prescribe a cardiac medication. This drug will be given through your IV. You blood pressure, heart rate, oxygen levels will be monitored during this time. Once an adequate dose of the drug is given, the doctor will check to see how effective it is in controlling your irregular rhythm.

When the EP study is completed, the doctor will remove the catheters. To prevent bleeding, pressure will be applied to the catheter insertion site until the bleeding stops. A small sterile dressing will be applied which will be removed the next day. No stitches will be required. You will return to a recovery area on a stretcher.

The catheter insertion areas require time to heal, so you will need to follow these steps:

  • Bed rest for 3-6 hours.
  • Do not cross your legs and keep the legs straight if the catheters were inserted in the groin. To sit up or bend your knees may cause bleeding at the site.
  • Report any symptoms to your nurse such as chest pain, swelling in the insertion sites, warmth, anything unusual.

The nurse will make sure you are given something to eat or drink, make sure you are comfortable, answer any questions or concerns, check your blood pressure and heart rhythm (EKG), help you with urination, etc.

What is Catheter Ablation?

The EP study and ablation procedure are very similar. In fact, your doctor may decide to do both procedures, one after the other, while you are in the EP lab. This possibility will be discussed with you prior to the study.

Catheter ablation is a non-surgical technique that is used to destroy heart muscle cells responsible for an arrhythmia. The procedure can be quite lengthy. An ablation procedure can last for 2-4 hours. This procedure is the preferred treatment for many types of arrhythmias.

During catheter ablation, a doctor guides a catheter through a vein in your leg to your heart. The catheter is positioned in the area of your heart responsible for the arrhythmia. Electrodes at the tip of the catheter emit radio frequency (heat) energy through it that destroys the heart muscle cells responsible for the arrhythmia.

Drug therapy for arrhythmias

If the doctor diagnoses you with a heart rhythm disturbance (arrhythmia) after the study, he/she will prescribe a medication (antiarrhythmic) to control your arrhythmia. Antiarrhythmic medications can help alleviate symptoms and prolong life. Some sample medications include:

  • Quinidine - used to treat patients with Supraventricular (SVT) and Ventricular Arrhythmias (VT), such as Atrial Fibrillation (AFib) or flutter, Paroxysmal Supraventricular Tachycardia (PSVT), and Premature Ventricular Contractions (PVCs). The drug comes in several forms, including Quinidine Sulfate (Ci-Quin) and Quinidine Gluconate (Duraquin).
  • Propranolol (Inderal) - decreases heart rate and contractility. Reduces the incidence of sudden cardiac death after a heart attack.
  • Sotalol (Betapace) - decreases heart rate, slows AV conduction, decreases cardiac output, and lowers blood pressure.
  • Amiodarone - used to treat SVT, PSVT, VT, Wolff-Parkinson-White (WPW) syndrome.

*Medications may not be the answer for treating your arrhythmia. If this is the case, your doctor will discuss other ways of treating your problem, such as a pacemaker or defibrillator (AICD).

Where is the test performed?

In the Cardiac Catheterization Lab.

How long does this test take?

An EP study usually takes 1-4 hours.