Electrophysiology (EP) studies help your doctor to determine the exact type of heart rhythm distrubance (abnormality in the speed or pattern of your heartbeat) you have. During the EP study one or more small flexible tubes (electrode catheters) are inserted in the groin or neck vein and gently threaded into the heart. The electrode catheters record electrical activity in the heart and find where and when these electrical signals begin and how often they are sent.

The electrode catheter can also send electrical signals to stimulate the heart. If these signals cause an abnormal heart rhythm (arrhythmia), medications can given through an IV line to test if they can stop or prevent the arrhythmia from occurring. Arrhythmias can also be stopped by using electrode catheters to regulate (pace) the heartbeat. In some cases an electric shock (defibrillation) is needed to stop the arrhythmia.