Book excerpt: In the fast paced world of clinical training, students are often inundated with the what of electrophysiology without the why. This new text is designed to tell the story of electrophysiology so that the seemingly disparate myriad observations of clinical practice come into focus as a cohesive and predictable whole. Presents a unique, conceptually-guided approach to understanding the movement of electrical current through the heart, the impact of various disease states and the positive effect of treatment Reviews electrophysiologic principles and the analytic tools which, when combined with a firm grasp of EP mechanisms, allow the reader to think through any situation Presents the mathematics necessary for the practice of cardiac electrophysiology in an accessible and understandable manner Contains accompanying video clips, including computer simulations showing the flow of electrical current through the heart, which help explain and visualise concepts discussed in the text Includes helpful chapter summaries and full color illustrations aid comprehension