Electrophysiology study (EPS) in medicine usually refers to a specialized heart test that maps and tests the heart’s electrical system to diagnose and treat abnormal heart rhythms (arrhythmias).

What is EPS in medical terms?

In cardiology, an electrophysiology study (EPS) is an invasive test where thin, flexible wires (catheters) with electrodes are threaded through a vein (usually in the groin or neck) into the heart.

These electrodes record the heart’s electrical signals and can also deliver tiny impulses to provoke or stop arrhythmias under controlled conditions.

Doctors use EPS to:

  • Identify the exact source of an abnormal rhythm inside the heart.
  • Decide on the best treatment (catheter ablation, medications, pacemaker, or ICD).
  • Assess the risk of serious events like sudden cardiac death in high‑risk patients.

How the procedure works

During an EPS:

  1. The skin over the vein (groin and/or neck) is cleaned and numbed.
  1. Small tubes (sheaths) are inserted into the vein, and catheters are advanced into the heart under X‑ray guidance (fluoroscopy).
  1. The electrodes on the catheters record electrical activity and can pace the heart to intentionally trigger arrhythmias for study.
  1. If needed, the doctor may perform catheter ablation in the same session, targeting and destroying tiny areas of heart tissue that cause the abnormal rhythm.

It is done in a specialized electrophysiology lab, not as open‑heart surgery, and often with sedation so the patient is comfortable but may be awake enough to follow instructions.

Why doctors order an EPS

Common reasons include:

  • Recurrent palpitations or unexplained fainting where an arrhythmia is suspected.
  • Known arrhythmias (like supraventricular tachycardia, atrial tachycardia, some ventricular tachycardias) where ablation is being considered.
  • Risk assessment after certain heart conditions to see if a defibrillator (ICD) is needed.

Other uses of “EPS” in medicine

In some medical and pharma contexts, EPS can also appear in names of companies or groups (for example, EPS Group, which supports clinical trials and post‑marketing surveillance) but that is more about branding than a specific test.

There is also EPS as shorthand for extrapyramidal symptoms in psychiatry (movement side effects from some antipsychotic medications), but that is a different concept from the cardiac electrophysiology study.

TL;DR:
In medical/cardiology contexts, “EPS” almost always means an electrophysiology study —an invasive test using catheters and electrodes inside the heart to analyze and treat abnormal heart rhythms.

Information gathered from public forums or data available on the internet and portrayed here.