Electrophysiology Study

What is an electrophysiology study?

The heart has its own electrical system, which tells the heart muscle when to contract. When that system misfires, the heart can beat too quickly, too slowly, or irregularly. An electrophysiology (EP) study is a test that examines this electrical system directly.

During the study, fine wires called electrode catheters are guided to the heart through a vein, usually in the groin. These wires record the heart's electrical signals from the inside, and can also be used to pace the heart — gently stimulating it to bring on the abnormal rhythm under controlled conditions, so it can be studied while your cardiologist is watching.

Why is it done?

An EP study allows your cardiologist to identify the precise origin and mechanism of an abnormal heart rhythm. This may confirm a diagnosis where other tests, such as an ECG or a Holter monitor, have not captured the rhythm, and it guides the decision about the best treatment.

In many cases, if an abnormal circuit is found, it can be treated in the same procedure with catheter ablation — delivering energy through the catheter to interrupt the circuit responsible for the arrhythmia.

What is involved?

The procedure is performed in a specialised cardiac catheter laboratory. It is usually carried out under local anaesthetic with sedation, so you are comfortable and drowsy throughout. The area in the groin is numbed before the catheters are inserted, and the wires themselves cannot be felt inside the heart. You may be aware of your heart racing at points during the study, as the rhythm is deliberately brought on and then settled again.

Your cardiologist will discuss with you beforehand what the study involves in your particular case, how long it is likely to take, what preparation is required — including any changes to your medications — and what the risks and benefits are for you.