This book incorporates the most up-to date information related to mechanisms and treatment of cardiac arrhythmia. Many of the topics discussed in this text reflect very recently undertaken research directions including genetics of arrhythmias, cell signalling molecules as potential therapeutic targets and trafficking to the membrane. These new approaches and implementations of anti-arrhythmic therapy derive from many decades of research as outlined in the first chapter by distinguished Professors Michael Rosen (Columbia University) and Michiel Janse (University of Amsterdam). The text covers changes in approaches to therapy over time, arrhythmias in multiple cardiac regions and over many scales, from gene to protein to cell to tissue to organ.