Coughtrie AL, et al. - The objective of this study is to establish a unique sample of proarrhythmia cases, ascertain the qualities of cases and estimate the contribution of individual drugs to the incidence of proarrhythmia within these cases. Antiarrhythmics, non-cardiac drugs and drug combinations were observed to be culpable in a large cohort of 124 clinically validated proarrhythmia cases. Potential clinical factors that may warn the prescriber of potential proarrhythmia include older women, underlying cardiovascular comorbidity, family history of sudden death and hypokalaemia.