Electrophysiology Study for Syncope

An electrophysiology study (EPS) is a specialised test to understand the “electrical system” of your heart, which is responsible for controlling your heartbeat.

When someone experiences syncope, which means they faint or pass out, it could be due to a problem with this electrical system. A left bundle branch block (LBBB) or right bundle branch block (RBBB) is a condition where there is a delay in the electrical current that travels through the heart, which can sometimes be related to these fainting spells. If you faint and have either LBBB or RBBB, then an electrophysiology may reveal the cause of your fainting. Sometimes an EP study is performed when the symptoms of your faint are typical of a cardiac cause.

The Procedure

During the electrophysiology study (EPS), 1-2 wires are inserted into the heart through a vein (femoral vein) in your groin. These are carefully passed into the heart under xray guidance. The wires measure the electrical signals in the heart to find out if there are any abnormalities that could explain why you’ve been fainting.

Results

If the EPS doesn’t show any problems, your doctor might suggest placing a (loop recorder). This is a small device implanted under the skin of your chest that continuously records the heart’s electrical activity over a long time (usually up to 3-5 years). It works like a “black box” that records how your heart is working so that if you faint again, your doctor can look at the information from right before and after you fainted to figure out why it happened. This helps in diagnosing the cause of syncope (fainting) when it’s not apparent during the EPS.

If the EPS reveals the reason why you passed out, then your doctor may advise placement of a (pacemaker) (if there is a problem of slow electrical conduction) or a (catheter ablation) (if you have a very fast heart rhythm).

Risks

The risks of a electrophysiology study are very low when no treatment is administered. There is a small risk of bleeding around the puncture site, and less than 1% risk of pericardial effusion (fluid around the heart), or blood clots in the vein.