Around 3.7 million individuals worldwide die each year from cardiac arrhythmias; this exceeds the total numbers of deaths from all cancers in the Western world. Despite major progress in interventional including device therapy, antiarrhythmic medication remains central to their management. In the late 1960s, Miles Vaughan Williams classified the existing drugs then used to treat cardiac arrhythmias. This was widely adopted worldwide in both clinical management and as guidance for the development of new drugs that have saved countless lives.