An EP study is an accurate method for assessing the heart’s electrical function. It allows doctors to locate abnormal sites inside the heart that may be causing serious arrhythmias (abnormal heart rhythms).
During an EP study, doctors insert special electrode catheters (long, flexible wires) into veins and guide them into the heart. Once inside, the catheters can sense electrical impulses in various areas of the heart; they can also be used to stimulate different parts of the heart.
EP studies are most useful in people who have had life-threatening arrhythmias and in people with persistent symptoms in whom suspected arrhythmias could not be diagnosed with other tests.
Where do EP Procedures Take Place?
The EP study is performed in a specially equipped room called an EP lab. In the room patients are transferred to a x-ray table. The table has a large camera above it and television screens close by. The equipment in the EP lab also includes heart monitors and various instruments and devices.
What Happens During the EP Study?
The area(s) where the catheters may be inserted (groin, arm, shoulder, or neck) is cleansed thoroughly. A local anesthetic is injected into the skin, to numb the area.
A small incision is made in the skin, and a needle is used to puncture the blood vessel (usually a vein) into which the catheters will be inserted.
The special electrode catheters used for the EP study are long and flexible wires that can conduct electrical impulses to and from the heart.
One or more catheters are inserted into the body and advanced toward the heart, while the staff follows their progress on a television screen. The catheters are then positioned inside the heart.
How is an EP Study Performed?
In general terms, the EP study is performed by doing two basic things:
Recording Electrical Signals – Electrode catheters sense electrical activity in various areas of the heart and measure how fast electrical impulses travel.
Pacing the Heart – Electrode catheters can also be used to deliver tiny electrical impulses to pace the heart. By doing so, doctors try to induce (bring on) certain abnormal heart rhythms, so that they can be observed under controlled conditions.
The EP study helps define the exact location of the heart’s abnormal electrical activity (this part of the study is called "mapping"). The location any type of arrhythmia you have will help determine the best treatment option for your problem.
What Can I Expect During the Study?
You will be awake during the procedure, although medication may be given to help you relax (it’s not uncommon to doze off during the procedure). The staff will be monitoring your progress constantly.
The EP study usually is not painful, although you may feel some pressure at the insertion site(s) during the insertion of the electrode catheters. There also may be some discomfort from lying still for a long time. You will not feel the catheters moving through the blood vessels and into your heart.
During the procedure, doctors may stimulate your heart with tiny electrical impulses. You will not feel these impulses, but they may induce the arrhythmia that has caused your symptoms in the past. Let the staff know if you feel lightheadedness, palpitations, chest pain, or shortness of breath.
The procedure can be quite lengthy. Depending on the particular arrhythmia you have and the findings, a complete study can last from 2 to 6 hours.
Is the EP Study Safe?
An EP study is a "minimally invasive" procedure that requires the insertion of catheters into the body. It therefore involves some risk. The risk is small, however, and the EP study is considered relatively safe.
Some patients may develop bleeding at the insertion site. Blood collects under the skin, resulting in local swelling and/or a "bruise" in the groin or arm.
Less frequently, EP studies may be associated with more serious complications. These include damage to the heart or blood vessels, formation of blood clots, and infection. Deaths are very rare.
Although most patients who undergo EP studies do not experience complications, you should be aware of the risk. To learn about your particular risk, you should discuss the matter with the doctor.
What Happens After the EP Study?
After the procedure is completed and the catheters are removed, the doctor (or nurse) will apply firm pressure to the insertion site(s) for about 10-20 minutes. This is done to prevent bleeding. If the insertion site was in the arm, the doctor may close the incision with a few stitches.
You’ll be transported to your room or the recovery area. Back in your room, you’ll lie flat in bed for 2 to 4 hours (occasionally longer), to allow a small seal to form over the puncture in the blood vessel. During that time, do not bend or lift the leg where the catheters were inserted. To relieve stiffness, you may move your foot or wiggle your toes.
Depending upon the results of the study, you may be sent home after several hours of observation, or the next day. When it’s time to go home, have a friend or family member drive you.
What Are the Next Steps?
The decision about what to do next will depend on the type of arrhythmia you have, the severity of your symptoms, and the results of the various diagnostic tests, including the EP study.
Your doctor will decide if your arrhythmia requires treatment, and if so, which option is best for you. Some options include medications, an artificial pacemaker, an implantable cardioverter-defibrillator, or catheter ablation therapy.
