Prolonged QTc interval and risks of total and cardiovascular mortality and sudden death in the general population: a review and qualitative overview of the prospective cohort studies.

There was no consistent evidence for increased risks of total or cardiovascular mortality or of sudden death, except perhaps for patients with prior cardiovascular disease. In the general population, if QTc interval prolongation is associated with any increase in mortality, that risk is likely to be small and difficult to detect reliably.