patch clamp and optical mapping. Allied professionals Mapping specialists (EP techs, EP physiologists) are typically educated up to the Bachelor's or Master's level and are employed by either a cardiac electrophysiology company or department. Often international certification such as Certified Electrophysiology Specialist (CEPS) by the International Board of Heart Rhythm Examiners (IBHRE) or EHRA Certified Electrophysiology Specialist (ECES) or equivalent is required. Subdiscipline Cardiac electrophysiology is a relatively young subdiscipline of cardiology and internal medicine. It was developed during the mid-1970s by Hein J. J. Wellens, professor of medicine at the University of Maastricht in the Netherlands and attending cardiologist at the Academic Hospital in Maastricht. In 1980 the first microprocessor based stimulator was developed there. Textbook The author of the definitive textbook in the field is by the late Mark E. Josephson, former Robinette Professor of Medicine and chief of cardiology at the University of Pennsylvania School of Medicine in Philadelphia, Pennsylvania, professor of medicine at Harvard Medical School, and attending cardiologist at Beth Israel Deaconess Medical Center in Boston, Massachusetts. The most recent published edition of Clinical Cardiac Electrophysiology: Techniques and Interpretations is the 6th edition in 2020. Professional societies The Heart Rhythm Society, founded in 1979, promotes education and advocacy for cardiac arrhythmia professionals (including cardiac electrophysiologists) and patients. European Heart Rhythm Association, a part of European Society of Cardiology, is active in Europe. Certification Founded in 1985 as NASPExAM, the International Board of Heart Rhythm Examiners (IBHRE) offers knowledge based board exams for physicians and allied health professionals working in the field of cardiac electrophysiology and cardiac rhythm device management. European Heart Rhythm Association (EHRA) provides knowledge and practical competency based certification to physicians and allied health professionals as well as accreditation of cardiac electrophysiology training centres in Europe and neighbouring countries. Mapping systems Carto Biosense-Webster, a subsidiary of Johnson & Johnson, produces a cardiac electrophysiology system called CARTO. The system is designed to visualise the real-time calculated position and orientation of a specialised RF ablation catheter within the patient's heart in order to minimise radiation exposure during fluoroscopy, increase the accuracy of targeted RF ablation and reacquisition of pacing sites for re-ablation. Its navigation system calculates the position and orientation of the catheter tip, using three known magnetic sources as references. The system uses static magnetic fields that are calibrated and computer controlled. Due to the nature of magnetic fields, the orientation may also be