In recent years there has been considerable interest in the diagnosis and understanding of ventricular repolarisation, particularly the QT interval prolongation and abnormal T and T/U wave morphology associated with torsades de pointes. Advances in ion channel cloning have greatly improved our understanding of the role of ionic channels in mediating cardiac repolarisation. Unfortunately, it is increasingly recognised that a number of drugs, both those associated with altering repolarisation, and others for non-cardiac conditions can increase the propensity for polymorphic ventricular...