An electrophysiology study is an invasive test of the heart's electrical system. Thin electrode catheters are passed through a leg vein and positioned inside the heart to record signals directly from the atria, the AV node region and the ventricles, and to stimulate the heart in a controlled way.
It can pinpoint the mechanism of a fast rhythm that surface ECGs cannot, and in most cases ablation is performed in the same sitting once the diagnosis is made. It is not a test for vague palpitations; it is used when there is already good reason to suspect a specific arrhythmia.
What Electrophysiology Study (EPS) shows
By measuring conduction times between recording sites, the study shows how well the sinus node, AV node and His-Purkinje system work. By delivering timed extra beats it can trigger and identify supraventricular tachycardias such as AV nodal re-entry, accessory pathway tachycardia and atrial tachycardia, and it locates the accessory pathway in Wolff-Parkinson-White syndrome and assesses how dangerous it is. In people with scarred ventricles it tests whether sustained ventricular tachycardia can be induced, which can inform the decision on an ICD. It may also explain fainting when conduction disease is suspected.
When Electrophysiology Study (EPS) is recommended
- People with documented or strongly suspected SVT who are considering ablation
- People with a Wolff-Parkinson-White pattern on ECG, particularly with symptoms or in high-risk occupations and competitive sport
- Unexplained fainting in someone with bundle branch block or a previous heart attack
- Wide-complex tachycardia of uncertain origin
- Risk assessment in selected people with structural heart disease or some inherited conditions
Limits and situations where another test is better:
- Occasional missed beats with a normal heart: a Holter or event recorder is the right test
- Atrial fibrillation is diagnosed on ECG; a diagnostic EPS adds little before AF ablation
- A negative study does not fully exclude an arrhythmia, since not every rhythm can be triggered on the day
- Blackouts or sustained racing heart with chest pain need emergency assessment locally first
How to prepare
- Fast for 6 hours
- Rhythm medicines such as beta blockers, flecainide or verapamil are often stopped 3 to 5 days beforehand, only on your cardiologist's instruction
- Blood thinners may be continued or paused depending on the plan
- Bring every ECG, smartwatch trace or monitor report that captured your symptoms
- Discuss in advance whether you consent to ablation in the same session
What happens during the test
The study takes 45 to 90 minutes, longer if ablation follows. The groin is numbed and two to four catheters are advanced to the heart under X-ray. Sedation is kept light, because deep sedation can suppress the arrhythmia. You will feel your heart being paced quickly and may recognise your usual palpitations when the rhythm is triggered; the team can stop it promptly with pacing. Afterwards the catheters are removed, the vein is pressed for several minutes and you rest flat for 3 to 4 hours.
Results and next steps
The electrophysiologist knows the result at the end of the test and explains it the same day. If a treatable circuit is found, ablation is usually completed there and then. If conduction disease is found, a pacemaker may be advised; if dangerous ventricular arrhythmia is inducible, an ICD may be discussed. A full report with tracings is provided for your home cardiologist.
- Test time: 45 to 90 minutes
- Results ready: Immediately
- Back to everyday activity: 2 to 3 days
Safety and risks
- Groin bruising or bleeding; vein clot is uncommon
- Triggered arrhythmias, which is the aim, and which occasionally need an electrical shock to stop
- Perforation of the heart wall with bleeding around the heart, in fewer than 1 in 500
- Damage to the normal conduction system, mainly a risk if ablation is performed near the AV node
- X-ray exposure, generally low
Arranging Electrophysiology Study (EPS) in Türkiye
A stand-alone diagnostic EPS is seldom worth a trip. It makes sense when combined with planned ablation, typically a 5 to 7 day visit. Have your ECG recordings reviewed remotely first so that the electrophysiologist can tell you how likely a curable rhythm is.
Send your previous reports and the question you want answered and a Clinic-Y coordinator replies within 24 hours with suitable teams and written, all-inclusive proposals side by side. Reviewing your case is free.
الأسئلة المتكررة
Is it frightening to have the arrhythmia triggered?
It feels like your usual episode, but you are monitored continuously and the rhythm can be ended within seconds. Most people find it reassuring that the cause is finally identified.
What if nothing is found?
A normal study makes several serious arrhythmias unlikely. An implantable loop recorder may then be offered to capture rare events over months or years.
Is EPS the same as ablation?
No. EPS is the diagnostic part. Ablation is the treatment that often follows immediately when a target is found.