(EP Study, EPS, Electrophysiology Studies)
An electrophysiological study (EP study) is an invasive procedure that tests the heart's electrical system. The electrical system of the heart generates the heart beat.
During an EP study, a small, plastic catheter (tube) is inserted through a vein in the groin (or neck, in some cases) and is threaded into the heart, using a special type of X-ray, called fluoroscopy, to guide the catheter. Once in the heart, electrical signals are sent through the catheter to the heart tissue to evaluate the electrical conduction system contained within the heart muscle tissue.
There are several ways in which EP studies may be performed to assist in diagnosing electrical conduction system abnormalities of the heart. For example, a dysrhythmia/arrhythmia (an abnormal rhythm) may be deliberately stimulated by a doctor during the EP study so that the underlying abnormal electrical circuitry can be identified. Likewise, in order to evaluate the effectiveness of an antiarrythmic medication, an attempt may be made to stimulate the dysrhythmia.
Mapping, another type of EP study, may be done to locate the point of origin of a dysrhythmia. If a location is found that is the cause of the dysrhythmia, an ablation (removal of the spot by freezing or heated radiofrequency waves) may be done, which should stop the dysrhythmia.
The results of the study may help the doctor determine further therapeutic measures, such as inserting a pacemaker or implantable defibrillator, adding or changing medications, performing additional ablation procedures, or providing other treatments.
Other related procedures that may be used to assess the heart include resting or exercise electrocardiogram (ECG), Holter monitor, signal-averaged ECG, cardiac catheterization, chest X-ray, computed tomography (CT scan) of the chest, echocardiography, magnetic resonance imaging (MRI) of the heart, myocardial perfusion scans, radionuclide angiography, and cardiac CT scans. Please see these procedures for additional information.
The heart is, in the simplest terms, a pump made up of muscle tissue. Like all pumps, the heart requires a source of energy in order to function. The heart's pumping action is regulated by an electrical conduction system that coordinates the contraction of the various chambers of the heart.
In the heart, an electrical stimulus is generated by the sinus node (sinoatrial node, or SA node), which is a small mass of specialized tissue located in the right atrium (right upper chamber) of the heart.
The sinus node generates an electrical stimulus regularly at 60 to 100 times per minute (for adults) under normal conditions. This electrical stimulus travels down through the conduction pathways (similar to the way electricity flows through power lines from the power plant to your house) and causes the heart's lower chambers to contract and pump out blood. The right and left atria (the two upper chambers of the heart) are stimulated first and contract a short period of time before the right and left ventricles (the two lower chambers of the heart). The electrical impulse travels from the sinus node (SA node) to the atrioventricular (AV) node, where impulses are slowed down for a very short period, then continues down the conduction pathway via the bundle of His into the ventricles. The bundle of His divides into right and left pathways to provide electrical stimulation to both ventricles.
When a problem develops with the heart's rhythm, there may or may not be any symptoms. The presence of a dysrhythmia is usually determined by an electrocardiogram (ECG). An ECG is one of the simplest and fastest procedures used to evaluate the electrical activity of the heart. By placing electrodes at specific locations on the body (chest, arms, and legs), a tracing of the electrical activity can be obtained.
The electrical activity of the heart is measured by the ECG machine, electronically interpreted, and printed out for the doctor's information and further interpretation.
One of the most common heart dysrhythmias/arrhythmias is premature ventricular beats, or PVCs. PVCs are just what they sound like: the ventricles beat sooner than they should. This means that the ventricle is contracting and pumping out blood before the atrium above it has completely pumped its blood volume into the ventricle. Most of the time, PVCs are harmless. In fact, almost everyone has them at one time or another. However, if PVCs occur too frequently (more than several times per minute), the heart is unable to pump an adequate volume of blood to the body, which can cause symptoms, such as weakness, fatigue, palpitations, or low blood pressure.
Other types of rhythm problems can have similar effects. Problems may occur when the heart beats too fast, too slow, or with an irregular rhythm. But whether the heart is beating too fast, too slow, or too irregularly, the effects are often the same as one or more of those described above. Some additional examples of rhythm problems include:
Some dysrhythmias, however, occur only intermittently, and cannot be seen on a routine ECG or even on a more sophisticated type of ECG, such as a signal-averaged ECG or a Holter monitor procedure (a prolonged recording of the heart rhythm over 24 hours or longer). If the doctor suspects a problem with the heart's conduction system and cannot adequately diagnose the problem with other tests or procedures, then he or she may also decide that an electrophysiology study is appropriate.
An EP study may be performed for the following reasons:
There may be other reasons for your doctor to recommend an electrophysiological study.
Possible risks of an EP study include, but are not limited to, the following:
You may want to ask your doctor about the amount of radiation from the fluoroscopy used during the procedure and the risks related to your particular situation. It is a good idea to keep a record of your past history of radiation exposure, such as previous scans and other types of X-rays, so that you can inform your doctor. Risks associated with radiation exposure may be related to the cumulative number of X-ray examinations and/or treatments over a long period of time.
If you are pregnant or suspect that you may be pregnant, you should notify your health care provider due to risk of injury to the fetus from an EP study. Radiation exposure during pregnancy may lead to birth defects. If you are lactating, or breastfeeding, you should notify your health care provider.
Patients who are allergic to or sensitive to medications or latex should notify their doctor.
For some patients, having to lie still on the procedure table for the length of the procedure may cause some discomfort or pain.
There may be other risks depending on your specific medical condition. Be sure to discuss any concerns with your doctor prior to the procedure.
An EP study may be performed on an outpatient basis or as part of your stay in a hospital. Procedures may vary depending on your condition and your doctor's practices.
Generally, an EP study follows this process:
After the procedure, you may be taken to the recovery room for observation or returned to your hospital room. You will remain flat in bed for a few hours after the procedure. The circulation and sensation of the limb where the catheter was inserted will be monitored. A nurse will monitor your vital signs, the insertion site, and circulation/sensation in the affected leg or arm.
You should immediately inform your nurse if you feel any chest pain or tightness, or any other pain, as well as any feelings of warmth, bleeding, or pain at the insertion site in your leg or arm.
Bed rest may vary from two to six hours depending on your specific condition.
In some cases, the sheath or introducer may be left in the insertion site. If so, the period of bed rest will be prolonged until the sheath is removed. After the sheath is removed, you may be given a light meal.
You may be given pain medication for pain or discomfort related to the insertion site or having to lie flat and still for a prolonged period.
You may resume your usual diet after the procedure, unless your doctor decides otherwise.
After the specified period of bed rest has been completed, you may get out of bed. The nurse will assist you the first time you get up, and will check your blood pressure while you are lying in bed, sitting, and standing. You should move slowly when getting up from the bed to avoid any dizziness from the long period of bed rest.
When you have completed the recovery period, you may be discharged to your home unless your physician decides otherwise. If this procedure was performed on an outpatient basis, you must have another person drive you home.
Once at home, you should monitor the insertion site for bleeding, unusual pain, swelling, and abnormal discoloration or temperature change at or near the injection site. A small bruise is normal. If you notice a constant or large amount of blood at the site that cannot be contained with a small dressing, notify your doctor.
It will be important to keep the insertion site clean and dry. Your doctor will give you specific bathing instructions.
You may be advised not to participate in any strenuous activities. Your doctor will instruct you about when you can return to work and resume normal activities.
Notify your doctor to report any of the following:
Your doctor may give you additional or alternate instructions after the procedure, depending on your particular situation.
The content provided here is for informational purposes only, and was not designed to diagnose or treat a health problem or disease, or replace the professional medical advice you receive from your doctor. Please consult your health care provider with any questions or concerns you may have regarding your condition.
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