What is an Electrophysiology Study (EPS) and catheter ablation?

EPS is a heart catheterization meant to definitely diagnose heart rhythm problems, whereas catheter ablation is performed based on EPS results to cure the problem. 

EP Study book

Electrophysiology Study Service

Why is EPS performed?

To definitely diagnose heart rhythm problems and abnormalities in the heart’s electrical system.

Is EPS and catheter ablation safe?

Diagnostic EP Studies, which use recording and pacing techniques to understand the heart’s electrical system, are considered very low risk.  Bruising at the IV sites is sometimes seen. 

Diagnostic EP Studies do not have any of the risks of Diagnostic Coronary angiography, which affects the coronary arteries and has risk of stroke, heart attack, aortic dissection, retroperitoneal hemorrhage, arterial pseudoaneurysm, arterio-venous fistula, urgent coronary bypass surgery, and kidney damage.

If catheter ablation proceeds, the risk remains low and depends on the sort of ablation being undergone.  For example, a Standard Ablation for SVT has a 1:1000-1:5000 risk of permanent pacemaker, depending on the literature cited.  Your Electrophysiologist will discuss your specific case with you.

What are the risks of EPS and ablation?

By far, the most common complication is bruising or bleeding at the IV site in the legs.  This is managed through proper IV site compression and dressings. 

The overall risk of any ablation depends on the particular rhythm being treated, although any ablation could theoretically perforate the heart and cause bleeding into the tissue surrounding it – the pericardium – this is exceedingly rare.  For some SVT ablations, there is a risk of permanent pacemaker between 1:1000 and 1:2000 cases; for others, a 1:1000-1:2000 risk of stroke.  Atrial fibrillation ablation carries a 1:1000 risk of stroke; very rare reports of esophageal injury or narrowing of the pulmonary veins.  Your Electrophysiologist will discuss all of this with you at your Clinic Visit.

How long is the procedure?

Time ranges from 1 hour for a diagnostic EPS, to 3-4 hours for a complex ablation.

Will the procedure hurt?

Placing the Intravenous tubes in the leg veins may cause a momentary stinging sensation, however, a numbing cream is placed on the skin before the procedure and pH-buffered local anesthetic is then placed in the skin and soft tissue to minimize this sensation.  In addition, patients are given intravenous medications for sedation and comfort at the start of the case and again as the case proceeds.  The remainder of the EP study is typically painless.  Although some patients do feel a vague chest pressure during radiofrequency ablation, the actual ablation application typically last 40-60 seconds.  Cryoablation is painless.

Am I asleep for the procedure?

General Anesthetic, which requires mechanical ventilation, is rarely very used as it adds risk of Pneumonia, heart attack and low blood pressure for example.  Instead, Conscious Sedation uses IV medications (fast-acting versions of Valium and Morphine) for sedation and comfort.  Many patients dose off and on during their cases.

How long will I need to stay in hospital?

Almost all cases are Same-day procedures.  Counting registration, preparation, the case itself, plus recovery, patients spend the better part of the day in the hospital.

Am I staying overnight?

Typically, discharge is same-day, usually in the afternoon or evening.  An overnight in our Short-Stay Unit may be recommended in certain cases, such as Subcutaneous ICD or AF ablation.

Is catheter ablation successful?

Yes – ablation provides a durable cure for almost all heart rhythm problems.