Electrophysiology Study (EP Study)

Electrophysiology is the study of the heart’s electrical system. The term electrophysiology study, also called an EP study, is an invasive procedure that tests the heart's electrical system. The electrical system of the heart generates the heart beat. The heart is 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 energy comes from an indwelling electrical conduction system.

An electrophysiology study may be performed for a number of reasons.

During an electrophysiology study , a small, plastic catheter (tube) is inserted through a vein in the groin (or arm, 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 an electrophysiology study may be performed to assist in diagnosing electrical conduction system abnormalities of the heart. For example, a dysrhythmia/arrhythmia (an abnormal rhythm) may be stimulated by the electrical signal, in which case medication may be given to treat the dysrhythmia. In order to evaluate the effectiveness of the medication given, another attempt is made to stimulate the dysrhythmia. Mapping, another type of electrophysiology 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 radiofrequency) may be done, which should stop the dysrhythmia.

The results of the electrophysiology study may help the St. John physician 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 ultrafast CT scan.

As with any procedure, there are risks involved with an electrophysiology study that the St. John’s Mercy physician will discuss with the patient before the procedure is performed.

The Heart Hospital at St. John’s Mercy has two dedicated electrophysiology laboratories featuring state-of-the-art imaging and mapping systems. Studies and procedures dealing with the heart's electrical system are performed in these labs.

For more information about the St. John's Mercy Heart Hospital, please call 1-866-78-HEART.