Intracardiac electrophysiology study (EPS) involves placing wire electrodes within the heart to determine the characteristics of heart arrhythmias.

Electrophysiology study - intracardiac; EPS - intracardiac

The study is performed in a hospital laboratory by a trained staff including cardiologists, technicians, and nurses. The environment is safe and controlled to minimize any danger or risk.

The cardiologist inserts a catheter through a small incision in a groin vein after cleansing the site and numbing it with a local anesthetic. This catheter is equipped with an electrode connected to electrocardiographic monitors.

The catheter is then carefully threaded into the heart using an x-ray imaging technique called fluoroscopy to guide the insertion. Electrodes are placed in the heart to measure electrical activity along the heart's conduction system and within heart muscle cells themselves.

Normal electrical activity is signaled from the heart's natural pacemaker known as the sinoatrial (SA) node. It then travels through the atria (the two chambers on the top of the heart), the atrioventricular (AV) node (connecting the atria to the ventricles), and the ventricles (the lower chambers of the heart).

Abnormal electrical activity can occur anywhere along this conduction system, including in the muscle cells of either the atria or ventricles. The electrodes inserted during EPS will map the type of arrhythmia you have and where the problem arises in your heart. This information allows your cardiologist to determine the severity of the problem (including whether you are at risk for sudden cardiac death) as well as appropriate treatment.

Test preparations are similar to those for a cardiac catheterization. Food and fluid are restricted 6 - 8 hours before the test. The procedure takes place in a hospital and you will wear hospital clothing. You must sign a consent form for the procedure.

Your health care provider will give you instructions regarding any changes to medications. Do not modify or stop taking any medications without consulting your health care provider.

A mild sedative is usually given 30 minutes before the procedure. You may not be able to drive home yourself if you are discharged the same day.

During the test, you are awake and able to follow instructions.

The procedure generally lasts from 20 minutes to 1 hour in the case of a simple EPS. It may take longer if other procedures are involved.

Before performing EPS, which is invasive, your cardiologist will try to identify a suspected arrhythmia using other, less invasive tests like ambulatory cardiac monitoring. If the abnormal rhythm is not detected by these other methods and your symptoms suggest that you have an arrhythmia, EPS may be recommended. Additional reasons that EPS may be considered include:

• To find the location of a known arrhythmia and determine the best therapy
• To assess the severity of the arrhythmia and determine if you are at risk for future cardiac events, especially sudden cardiac death
• To evaluate the effectiveness of medication in controlling an arrhythmia
• To determine if the focus (the place from where the arrhythmia is coming) should be ablated
• To evaluate the need for a permanent pacemaker or an implantable cardioverter-defibrillator (ICD)

If ablation is thought to be the appropriate therapy, it is performed at the time of EPS.