What is Electrophysiology (EP)?

Submitted by Dr. David Adler on December 13, 2018

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When someone's heart doesn't beat normally, doctors use EP to find out why

If love isn't the reason your heart is racing, it could be an abnormal heart rhythm or arrhythmia. It's usually not dangerous, but can be scary. We can put your mind – and your heart – at ease. Electrical signals usually travel through the heart in a regular pattern. Heart attacks, aging and high blood pressure may cause scarring of the heart. This may cause the heart to beat in an irregular (uneven) pattern. Extra abnormal electrical pathways found in certain congenital heart defects can also cause arrhythmias.

Older woman Exercising her heart outside

Doctors Use EP to See:

  • Where an arrhythmia is coming from.
  • How well certain medicines work to treat your arrhythmia.
  • If they should treat a problem by correcting abnormal electrical signals. This procedure is called catheter ablation.
  • If a pacemaker or implantable cardioverter defibrillator (ICD) might help you.
  • If you are at risk for heart problems such as fainting or sudden cardiac death due to cardiac arrest (when your heart stops beating).

At a hospital or clinic, doctors and nurses do EP in a room that has special equipment for the tests. You may hear this room called the electrophysiology laboratory, or EP lab. Some call it the catheterization laboratory (cath lab).

During the Test

  1. A nurse will put an IV (intravenous line) in your arm. You’ll get medicine (a sedative) that will help you relax. But you’ll be awake and able to follow instructions during the test.
  2. Your nurse will clean and shave the part of your body where the doctor will be working. This is usually in the groin but may be the arm or neck.
  3. A local anesthetic will be given to make the area numb. Your doctor will make a needle puncture through your skin and into your blood vessel. A small straw-sized tube called a sheath will be inserted into your artery or vein. The doctor will gently guide several specialized EP catheters into your blood vessel through the sheath and advance them to your heart. A video screen will show the position of the catheters. You may feel some pressure in the area where the sheath was inserted, but you shouldn’t feel any pain.
  4. Your doctor will send small electric pulses through the catheters to make your heart beat at different speeds. You may feel your heart beat stronger or faster.
  5. Electrical signals produced by your heart will be picked up by the special catheters and recorded. This is called cardiac mapping and allows the doctor to locate where arrhythmias are coming from.
  6. Your doctor will remove the catheters and the IV line. Your nurse will put pressure on the puncture site to stop any bleeding.
  7. An EP study usually lasts 1 to 4 hours.

If the type and location of the arrhythmia is identified and an appropriate therapy decided, cardiac ablation or insertion of a pacemaker or ICD may be performed during or immediately after the EPS.

Dr. David Adler is a cardiologist on staff at Chesapeake Regional Medical Center