Written by Dimitrios Vrachatis, Specialist Cardiologist, PhD, National and Kapodistrian University of Athens.
What is an electrophysiology study?
An electrophysiology study, or EPS, can be described simply as an electrocardiogram performed from inside the heart.
What information does it provide?
The study provides detailed information about the location and function of the heart’s electrical system. Dynamic tests can also be performed, with or without specific medication.
It assesses the integrity of the conduction system, for example to establish whether a pacemaker is needed, and accurately diagnoses arrhythmias.
Special tests assess the heart under stress by attempting to induce potentially dangerous arrhythmias. This helps identify future risk and guide care, such as defibrillator implantation.
How is the study performed?
This is an invasive diagnostic procedure. The patient lies on the procedure table in the electrophysiology laboratory. The groin is shaved if not already prepared, because access through a vein, usually the femoral vein, is required. Local anaesthesia is given before puncture.
Special sheaths are inserted, through which electrode catheters are advanced into the right heart chambers. Limited fluoroscopy guides this painless process.
The main examination then records conduction system function. Special tests are performed through the electrodes, with or without appropriate medication.
How long does it take?
The main part of a basic study usually takes less than an hour. Mapping or arrhythmia ablation during the same session can substantially increase this time. Preparation and transfer may also extend the time spent in the laboratory.
When is it needed?
It may be used to investigate loss of consciousness, diagnose or classify arrhythmias, confirm an accessory pathway in pre-excitation syndromes such as Wolff–Parkinson–White (WPW), or assess the risk of life-threatening arrhythmias in people with or without heart failure.
Can ablation be performed during the same session?
Diagnosis and treatment can be combined because vascular access is already available for the necessary catheters. Based on the medical history, this will have been discussed beforehand with the patient and their family.
Are there risks or complications?
Diagnostic EPS is relatively safe, but invasive. Overall complications occur in approximately 2% of cases, mostly related to peripheral venous catheterisation, particularly a local haematoma. Atrial fibrillation may be induced and is usually corrected by cardioversion before the patient leaves the laboratory.
Life-threatening arrhythmias may also be intentionally induced as part of the diagnostic assessment. In the controlled laboratory setting, they are stopped with appropriate measures; outside hospital, the same arrhythmias might be fatal. Mechanical cardiac complications and death have been reported very rarely.
Can I get up immediately afterwards?
No. You remain in bed for a few hours. Once haemostasis is confirmed, meaning there is no bleeding from the puncture site, you can get up.
For a few days, protect the area by avoiding strenuous movements, such as large steps or driving.
How long will I stay in hospital?
If only a diagnostic study is performed and there are no complications, discharge is usually the same afternoon or the following morning.