The aim of this thesis is to briefly summarise the antiarrhythmic agents that were established in the original Vaughan Williams classification system as well as explore the modernised or revised classification and the new agents that have been added. The original Vaughan Williams classification, which divided the drugs based on their effect on the different parts of the cardiac action potential, has 4 categories; Class I agents, Class II agents, Class III agents and Class IV agents. The revised classification incorporated new drugs into the existing classes and introduced new classes altogether (Class 0, Class V, Class VI and Class VII agents). Also, some novel/new antiarrhythmic targets and novel formulations of already existing agents will be explored as well.