Block of the Rapid Component of the Delayed Rectifier Potassium Current by the Prokinetic Agent Cisapride Underlies Drug-Related Lengthening of the QT Interval

Abstract

Block of I(Kr) gives an explanation to lengthening of cardiac repolarization observed in isolated guinea pig hearts. Potent block of I(Kr) is also likely to underlie prolongation of the QT interval observed in patients receiving clinically recommended doses of cisapride as well as severe cardiac toxicity (torsades de pointes) observed in patients with increased plasma concentrations of the drug.