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Electrophysiology Study (EPS)

An electrophysiology (EP) study is a test used to understand and map the electrical activity within your heart. An EP study may be recommended in people with heart rhythm problems (arrhythmias) and other heart problems to understand the exact cause and determine which treatment is most likely to be effective. An EP study involves placing diagnostic catheters within your heart and running specialized tests to map the electrical currents.

An EP study can also be used to predict the risk of sudden cardiac death.Your doctor may recommend an EP study if you:

  • Have an abnormal heart rhythm (arrhythmia). If you’ve been diagnosed with an arrhythmia, such as atrial fibrillation, atrial flutter, tachycardia, ventricular tachycardia or supraventricular tachycardia, your doctor may recommend an EP study to better understand how electrical signals move in your heart and how best to treat your condition.
  • Are undergoing cardiac ablation. An EP study is done at the beginning of a cardiac ablation procedure for arrhythmia. Cardiac ablation uses heat or cold energy to create scar tissue in the heart to block erratic electrical signals.
  • Experience a temporary loss of consciousness (syncope). People who experience syncope may undergo an EP study to understand the cause.
  • Have a risk of sudden cardiac death. If you have a heart condition that increases your risk of sudden cardiac death, an EP study may help your doctor better understand your risk.
  • Are undergoing heart surgery. If you’re preparing for a heart operation in which cardiac ablation may be performed at the same time, your doctor may recommend an EP study.


Your doctor will evaluate you and may order several tests to evaluate your heart condition. You’ll need to stop eating and drinking the night before your test. If you take any medications, ask your doctor if you should continue taking them before your test.In some cases, you’ll be instructed to stop taking medications to treat a heart arrhythmia several days before your test.If you have an implanted heart device, such as a pacemaker or implantable cardioverter-defibrillator, talk to your doctor to see if you need to take any special precautions.


An EP study is performed in the hospital. Before your procedure begins, a specialist will insert an intravenous line into your forearm or hand, and you’ll be given a sedative to help you relax. In some situations, general anesthesia may be used. After the sedative takes effect, specialist will numb a small area near a vein in your groin, neck or forearm. Your doctor will insert a needle into the vein and place a tube (sheath) through the needle. Your doctor will thread catheters through the sheath and guide them to several places within your heart. Your doctor may inject dye into the catheter, which helps your care team see your blood vessels and heart using X-ray imaging. The catheters have electrodes at the tips that can be used to send electrical impulses to your heart and record your heart’s electrical activity. Cardiac mapping is the process of determining the best location to apply cardiac ablation to treat arrhythmia. Imaging tests are used to create a map of your heart that’s used during the procedure. An EP study can take one to four hours.

After procedure:

Following your EP study, you’ll be moved to a recovery area to rest quietly for four to six hours to prevent bleeding at your catheter site. Your heartbeat and blood pressure will be monitored continuously to check for complications. Most people go home the same day. Plan to have someone else drive you home after your test and to take it easy for the rest of the day. It’s normal to feel some soreness for a few days where the catheter was inserted.


An EP study carries a risk of complications, including:

  • Bleeding or infection at the site where your catheter was inserted
  • Damage to your blood vessels where the catheter may have scraped as it traveled to your heart
  • Puncture of your heart
  • Damage to your heart valves
  • Damage to your heart’s electrical system, which could worsen your arrhythmia and require a pacemaker to correct
  • Blood clots in your legs or lungs (venous thromboembolism)
  • Stroke or heart attack
  • Death in rare cases