Electrophysiology is the study of the way electricity interacts with cells and tissues in the body and their electrical properties. It particularly involves the study of the electrical rhythms of the heart. Other areas of electrophysiology are comprised of the study of the electrical impulses carried by the nerves. On the microscopic scale, some electrophysiologists study the activity of ions and proteins in cells. In practice, most of electrophysiology concerns itself with correcting heart disorders such as arrhythmias and certain types of tachycardia.

Under normal circumstances, electricity flows from cell to cell through the heart, in an even, predictable pattern. When a disturbance in this system occurs, it leads to an uneven heartbeat rhythm, or arrhythmia. To diagnose the exact cause of an arrhythmia, a doctor will often perform an electrophysiology study. This may involve a variety of tests, both invasive and noninvasive, to find the source of the electrical disturbance.

One of the more invasive tests consists of the insertion of electrode catheters into a vein, then threading these catheters back to the heart to record its various electrical impulses from close up. Through this technique, the area or areas of the heart that are causing the arrhythmia can be identified, and treatment can be pursued accordingly. This is one of the distinctive tests that comprise an electrophysiology study, as opposed to a simpler procedure.

Invasive testing is sometimes necessary to study cardiac arrhythmias. An electrocardiogram (EKG), while it traces the electrical impulses of the heart while it is beating, offers little insight about the nature of an arrhythmia, unless it catches an actual arrhythmia event, which it rarely does. An electrophysiology study involves actually provoking an arrhythmia event once the electrodes have been placed. This leads to the collection of valuable data, which can help predict future health issues and decide whether it may be necessary to implant a cardiac pacemaker.

A pacemaker is just one possible treatment option for an arrhythmia. Drugs also exist to treat these conditions, as do implantable defibrillators. These devices are somewhat similar to pacemakers, and are implanted when serious conditions are observed during an electrophysiology study, such as ventricular tachycardia, or V-tach. If the defibrillator detects a problem, it will deliver electrical impulses to the heart in order to restore a proper rhythm. These devices are generally much more effective than medications in preventing sudden deaths from cardiac arrhythmia.