Before the day of the electrophysiology (EP) study, patients should discuss their medical history with their physician and inform him or her of any medications currently being taken. Certain medications may need to be discontinued or dosages reduced at some point prior to the test. Also, patients with diabetes are advised to consult with their physician regarding food and insulin intake, because people are generally asked to stop eating and drinking for about six hours before the test.

Just prior to the procedure, the area to receive the electrode catheter is shaved and sterilized to prevent infection. A mild sedative is usually administered.

The EP study may take up to three hours. The patient is first taken to a sterile EP laboratory that resembles an operating room with monitoring devices, video display equipment and x-ray cameras. Once the patient is made comfortable, heart and blood pressure monitoring begin, and an intravenous (I.V.) line is inserted. The area to receive the electrode catheter is then locally anesthetized. The injection of the local anesthesia may result in a brief period of discomfort. This is normal and should be no cause for concern. In fact, this will likely be the most uncomfortable phase of the procedure.

Once the local anesthesia takes effect, the physician will prepare to insert the electrode catheter. Depending on the point of puncture (e.g., the groin), a small incision may be made or a needle may be inserted into a blood vessel. The electrode catheter, which is connected to a computer that will record the data, is then guided with the assistance of an x-ray camera toward and into the heart.

Once in place, the electrode catheter will record electrical activity to assess the presence of abnormal heart rhythms (arrhythmias). The physician may also administer a small electrical shock during the procedure in an attempt to stimulate an arrhythmia.

Depending on what the physician finds, he or she may use the opportunity to perform an ablation while the catheter is still in place. During this procedure, radiofrequency energy is used to destroy selected sections of cardiac tissue that are causing abnormal heart rhythms.

At the conclusion of all procedures, the catheter is withdrawn. Pressure is placed on the point of puncture and, if an incision was made, it will be stitched up (sutured).

After leaving the EP laboratory, patients will remain in bed with their legs straight for several hours. Medical staff will regularly check vital signs, check the point of puncture for swelling or infection, and administer pain medications as necessary. Patients may remain in the hospital for 24 hours for observation. The results of the study may be available before patients leave the hospital, or in the next few days.

Further treatment may include the implantation of a pacemaker or implantable cardioverter defibrillator or a prescription for antiarrhythmic medications.