[Partial atrioventricular block and prolonged QT interval in 4 premature infants receiving diphemanil]

Four premature infants presenting with episodes of bradycardia in the first weeks of life were given diphemanil. One of them received an overdose accidentally. Paradoxically, this induced a permanent bradycardia leading to the discovery of a grade II A-V block as well as a prolonged QT interval. Discontinuation of the drug resulted in a prompt normalization of these changes. It is felt that this anticholinergic therapy may have caused a prolongation of the QT interval and, therefore, a partial A-V block in case of sinus tachycardia. Thus, such a therapy should not be given to young premature infants without having checked the QT interval on a ECG tracing and having made sure that it is adapted to the actual heart rate. It is also advised to reduce usual doses.