Cardiac arrhythmia, a disruption of the heart beat, is a widespread and growing problem in an ageing population.  Of particular import is Atrial Fibrillation (AF), the most common serious arrhythmia and one that can lead to serious health problems.  There are numerous non-pharmacological therapies for the treatment of AF, but the risk and expense make them unsuitable for widespread application.  There are also many existing drug therapies, but efficacy is poor, their mechanisms are often poorly understood, and they can in some cases exacerbate the problem.  This essay introduces the mechanisms behind heart function and arrhythmia and examines some existing therapies.  There is some discussion of efforts to model the function of the heart, before particular attention is given to AF and a particular piece of research that aims to explain and validate the action of a particular drug.  Finally there is some speculation as to how current research could yield invaluable insight.