Objective: To examine the effect of cisapride on the corrected QT (QTc) interval in infants over a 14-day period.
Study design: A prospective cohort study of infants receiving cisapride (0.8 mg/kg per day). Twelve-lead electrocardiograms were obtained before and 3, 5, 7, and 14 days after cisapride initiation.
Results: Fifty infants completed the study; none had arrhythmias. Fifteen of 50 infants (30%) developed QTc interval > or =450 msec; QTc interval normalized in 13 of 15 infants. Infants with QTc interval on day 3 > or =2 standard deviations above the mean baseline QTc interval (401+40 msec) were more likely to develop prolonged QTc interval (p<0.0001).
Conclusion: QTc interval prolongation was noted in 30% of infants. Subsequently, the majority of those infants had QTc interval normalization by day 14 of cisapride therapy. QTc interval 3 days following cisapride initiation may identify infants at risk for transient QTc interval prolongation. With appropriate monitoring, hospitalized infants receiving cisapride may have improved gastrointestinal motility without cardiac morbidity.