Any invasive procedure that requires catheters to be inserted in the body assumes some risk, however, the risk is quite small and the electrophysiology study is considered to be relatively safe.

Some patients may develop bleeding at the site of the insertion of the catheter, very rarely blood clots form inside the chambers of the heart or there is perforation of the vessels of the heart or heart valves.

Death during or related to the electro physiology study is extremely rare: less than 1 in 3,000. Following the electrophysiology study, one has to lay flat between four to six hours, and patients either will be admitted for further therapy with medications, or abilation, or may be discharged at that time, depending upon the results of the test.

• Your doctor may advise you to stop taking certain medications before your EP study to ensure more accurate results. EP studies require that you have an empty stomach. In most cases you will not be permitted to eat or drink anything after midnight. It’s important to get a good night’s sleep.
• Hospital admission usually occurs the same day as your test. During the EP study you will be awake, but you may be given a medication to help you relax. Electrodes will monitor your heart rhythm and rate. This may require that some areas be shaved in preparation.
• Prior to the test, an intravenous (IV) line will be started through which your physician can administer medications or extra fluids you may need.
• In preparation for the study, the groin area is sterilized and numbed so a catheter can be inserted.
• Remember you will be safely monitored in the EP lab by a highly–trained team of doctors, nurses and technicians throughout the procedure.
• EP studies usually last from two to four hours. After the catheters are removed, pressure will be applied to the puncture site just long enough to stop the bleeding. No stitches are required but a sterile dressing will be applied and can be removed the next day.

Supraventricular Tachycardia
Tachycardia is when the heart rate is faster than normal. Abnormal rhythms which affect the racing of the upper chamber are called supraventricular tachycardia.

The most common type is Atrioventricular (AV) node reentry: two different electrical pathways within the region of the AV node allow impulses to go in an uncontrolled, rapid, regular heart rate.

Wolff–Parkinson–White Syndrome is the combination of an accessory pathway that conducts from the atria to the ventricles (Creating a “Delta” wave on the electrocardiogram) and the occurrence of atrioventricular reentrant tachycardia and/or atrial fibrillation. Except for symptoms caused by these rhythms, there do not appear to be any long–term adverse effects of the Wolff–Parkinson–White Syndrome.