Irregular heartbeat or cardiac arrhythmias is a severe medical condition. The close mechanisms of cardiac arrhythmias remain unidentified to experts. Genetic researches on ionic modifications, the electrocardiographic characteristics of cardiac rhythm and multiple diagnostic tests have achieved more in the last few years than in the history of cardiology. Similarly, treatments to avoid or cure such disorders are rising speedily. This book discusses uncommon heart rhythm disorders and various miscellaneous topics related to cardiac arrhythmias. It also elucidates various aspects related to cardiac electrophysiology. This book is a compilation of several well conducted researches accomplished by experts all over the world and will provide valuable insights to its readers.