Intracardiac Electrophysiology Study (EPS Test)

Intracardiac Electrophysiology Study (EPS Test)

The heart plays a vital role in the sound functioning of our body. It is also an indicator if anything goes wrong inside our body. Sometimes the heart beats irregularly. It is either too fast (tachycardia) or too slow (bradycardia). Due to which patient feels uneasiness and sometimes witness major health issues. Medical science has found out a method to study the electrical signals produced in the heart and cause of fluctuations in the rhythm. It is known as EP study or EPS test (Intracardiac Electrophysiology study).

Heart’s Electrical System

The heart has four chambers. Upper chambers known as (atria) pumps blood to the lower chamber (ventricles). It requires an electrical impulse to start a heartbeat.
The heart’s natural pacemaker sinoatrial (SA) node originates the heartbeat.

These impulsestravel through atria signaling them to contract and received by the atrioventricular (AV) node. The AV node acts as a relay center to delay the impulse before sending it from the atria to the ventricles. The impulse then spreads throughout the muscle of the ventricles, stimulating them to contract.
Impulses are generated by the sinus node at 60 to 100 beats per minutes.

Facts About EPS Test:

  • Helps in finding the root cause of Arrhythmia (irregular beating)
  • Helps in finding out the exact treatment which is required like medicine, a pacemaker, cardiac ablation, cardioverter defibrillator (ICD) or surgery.
  • The test is conducted in Electrophysiology (EP) lab or Catheterization (Cath) Lab.
  • During the test patient remains awake.

Ep Study or EPS Test

We are discussing some of the reasons for the abnormal heart rhythm and need for the test to be done.
1. Due to high blood pressure, aging, cardiac arrest, etc. the pattern of beating fluctuates.
2. The test is performed to have vigilance over the heart’s electrical system.
3. In order to find out the point of occurrence of the abnormal rhythmic activity.
4. To decide the best therapy as per the requirement of the body.
5. To access the risk of sudden cardiac arrest.
6. To watch the effect of medicines, if there is an abnormality.
7. In extreme conditions, to find out the need of pacemaker or implantable cardioverter defibrillator.

Catheter Ablation

It is a procedure through which a catheter is placed inside the body through the arm or leg vein. A catheter has 4-8 mm metal tip which delivers radio frequency to various parts of the heart. The area to ablate is selected primarily on two bases. Vector analysis is done to see how arrhythmia activates the heart (north-south, east-west) or by moving the catheter to warmer or colder portion (trial method).
Electro physiology also deals with the placement of cardiac devices like pacemakers, Defibrillators or cardiac resynchronization therapy (CRT).


They are needed if the heart has a problem in conducting impulses from upper to lower chambers.

Implantable Cardioverter Defibrillator:

They are used if there is a life threatening arrhythmia. On inserting it automatically monitors heart and delivers a shock to restore the heart to normal.

Things to be Taken Care Before EPS Test

A patient should not eat or drink anything 6 to 8 hours before this test so as to avoid vomiting during the procedure. A consent form should be signed for the test. If you are on any regular medication, then no changes have to be made without health care provider’s suggestion. It is advisable that the patient should be accompanied by someone as they can’t drive for 24 hours.

How the EPS Test is Performed?

Cardiologist, technician, and nurses will be there to help you with this process. The complete process will take 1 to 4 hours of time.
In order to study the activities of your heart, there are some things which are needed like an X-ray guide, Sheaths, a catheter (wire or electrodes).

  • To begin with an anesthesia is given to the groin (an area which is to be punctured like an arm or thigh) or neck to numb the portion.
  • Sheaths are placed by the arm or thigh through which catheter is passed into the body.
  • A thin tube (catheter) is inserted into a blood vessel going to the heart.
  • A moving X-ray guide is used to exactly place the electrodes.
  • 3 to 5 catheters are generally used in the procedure.
  • This specialized electrode is designed for EP studies lets them send an electrical signal to the heart and records the electrical activities by the heart.
  • The procedure helps in finding the pin point for the irregular beating.
  • The test determines the placement of a pacemaker.
  • If there are small areas or portions causing the problem in the patient’s body, then they are destroyed during the procedure.

Commonly Found Results During The Procedure

1. Heart Block
2. Flutter or Atrial Fibrillation
3. Sinus Syndrome
4. Ventricular Fibrillation
5. Wolff- Parkinson (White syndrome)
6. Supraventricular tachycardia (collection of abnormal heart rhythm that starts in the upper chamber of the heart.

EPS Study – Risks Involved

The procedure is safe in most cases. However, sometimes the below risks are found in a few patients:
Arrhythmias, Bleeding, Blood clot, Heart Attack, Injury to veins, low blood pressure or a stroke.

After EPS Test

You will be moved to the recovery room to take rest for 1 to 3 hours. During this period keep the arm or the leg used for the test straight. The doctor will check if there is bleeding or clot in the punctured site. Before leaving Doctor may tell you the results and will be giving instructions to be followed at home.
Most people start eating or having regular medicines 4 to 6 hours after the test.
The puncture site may sore and will have a bruise which is normal.

When To Be Alert And Contact Your Cardiologist

  • Punctured site swell or fluid coming out.
  • Hands or feet changes color.
  • Any portion of the body is cold, numb or tingles.

Hence, this study investigates the cause, location of origin and the best treatment for various abnormal heart rhythms.
To enjoy real pleasures of life one needs to remain healthy. A person has more capacity to perform any task for longer hours. Means are there in the developing medical world, but at the same time, it’s our responsibility to take care of the soundness of the heart.

Medically Reviewed By
Dr. Kaushal M. Bhavsar (MBBS, MD)Assistant Professor in Pulmonary Medicine, GMERS Medical College, Ahmedabad