QT as a safety biomarker in drug development.

The cardiovascular safety of new drugs is an overarching concern for all stakeholders: the pharmaceutical industry and the US Food and Drug Administration (FDA) prior to approval and doctors and patients during postrelease drug use. Of the many cardiac safety concerns that accompany development of new drugs--including those related to vasculature and valvular tissue, the potential for myopathies, and the possibility of other electrophysiologic perturbations--the most pressing concern is the potential for ventricular arrhythmias causing sudden death.