Heart test
Electrophysiology Study
An electrophysiology (EP) study passes fine wires into the heart through a vein to map its electrical activity and diagnose abnormal heart rhythms.
Quick answer
Electrophysiology Study: what it is and what the results mean
An EP study is an invasive test in which thin, flexible wires (electrode catheters) are guided through a vein, usually in the groin, into the heart. They record and stimulate the heart’s electrical signals to pinpoint rhythm problems.
- Why it is done: It is used to investigate abnormal heart rhythms (arrhythmias), find where an abnormal rhythm starts, assess the risk of dangerous rhythms, and guide treatment — often leading directly to catheter ablation during the same procedure.
- Understanding results: The study identifies the type and origin of an arrhythmia.
What it is
An EP study is an invasive test in which thin, flexible wires (electrode catheters) are guided through a vein, usually in the groin, into the heart. They record and stimulate the heart’s electrical signals to pinpoint rhythm problems.
Why it is done
It is used to investigate abnormal heart rhythms (arrhythmias), find where an abnormal rhythm starts, assess the risk of dangerous rhythms, and guide treatment — often leading directly to catheter ablation during the same procedure.
What to expect
It is done in a specialised lab, usually with local anaesthetic and sedation. Catheters are inserted through a vein and positioned in the heart under X-ray guidance; the heart’s rhythm is tested. It can take one to several hours.
Understanding the results
The study identifies the type and origin of an arrhythmia. Findings guide treatment, which may include ablation (burning or freezing the abnormal area), medicines or a device such as a pacemaker or defibrillator.
Good to know
Risks and limitations
It is generally safe but, as an invasive procedure, carries small risks of bleeding or bruising at the insertion site, damage to a vessel or the heart, and rarely serious rhythm problems. These are closely monitored.
Education and reference only. This explains the test in general terms and is not medical advice. Always follow the specific instructions from the team arranging your test, and discuss your results with your clinician.
Answers
Electrophysiology Study: frequently asked questions
Is an EP study the same as an ablation?
An EP study maps the heart’s electrical activity, while ablation treats an abnormal area. They are often done together — the study locates the problem and ablation treats it in the same session.
Will I be awake during the procedure?
You usually have sedation to keep you relaxed and comfortable rather than a full general anaesthetic, though this varies. Your team will explain what to expect for your procedure.
Related tests
Other heart test investigations
Sources
Where this is drawn from
- NHS — Tests and treatments
- NICE — diagnostic guidance
- British Cardiovascular Society / relevant professional body
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