What is Cardiac Electrophysiology (EP)?

Cardiac Electrophysiology (EP) is the science of the electrical system of the heart. Cardiac Electrophysiology evaluates the normal and abnormal transmission of electrical impulses and their influence on the contraction of the heart muscle, thus creating a heart beat. A specialist in cardiac electrophysiology is known as an electrophysiologist.

Why is EP Study Needed?

The beating of the heart is controlled by the heart's electrical system. The electrical system controls the speed and rhythm of your heartbeat. If a problem occurs in the electrical system, the heart rhythm may be disrupted resulting in an irregular heart beats or arrhythmias. These arrhythmias can cause the heart to pump less effectively.

In order to diagnose an arrhythmia a physician would order a test. The test or otherwise known as an EP study is an invasive test to study the electrical activity of the heart by inserting one or more catheters from the blood vessels in the groin region to inside the heart chambers.

An EP Study Would

  • Determine the cause of an abnormal heart rhythm.
  • Locate the site of the origin of the abnormal rhythm.
  • Provide accurate information to determine the best treatment for an abnormal rhythm.

What Preparation is Needed?

  • Nothing to eat or drink after midnight
  • It is important for the patient to ask his doctor:
    • How to adjust insulin and food intake prior to the test if he is a diabetic
    • If he should take his regular medications the morning of the test
    • If taking blood thinners (ie. Coumadin), should they be withheld and, if so, how long prior to the procedure
  • Leave all valuables at home.
  • Please come prepared to stay overnight.
  • Make arrangements to be driven home.
  • The nursing department will contact you with specific instructions regarding your medications.


  • Pre-register 1-3 days prior to the day the test is scheduled. This will save considerable time on the day of test.
  • Please call 310-517-4754 to pre-register.
  • Plan to arrive 2 hours before the scheduled time of the test.
  • Enter the hospital through the main lobby from the visitor parking lot on the east side of the hospital.
  • Check in at the information desk in the main lobby.
  • The patient will be escorted to the Short Stay Department.

State-of-the-Art Technology

The catheterization and elctrophysiology Laboratories in the Torrance Memorial Lundquist Cardiovascular Institute was the first to attain the state-of-the-art anatomical mapping system, CARTO3, which enhances physician's ability to track the catheter's position during EP procedures to locate and treat the area(s) that are causing arrhythmias.

The speed, precision and clarity of the updated system are especially important in treatment of atrial fibrillation or "A Fib."