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[The authors respond:]
We appreciate John Morphet's letter and are pleased to respond. In our article, we stated that electrocardiography is not recommended as a routine strategy for assessing future risk of sudden infant death syndrome.1 The cost-effectiveness of such screening in infants without a family history of sudden cardiac death has been studied, but the results have been mixed. The authors of the only North American study concluded that electrocardiography was indicated only in selected groups of infants, such as those with symptoms related to apnea or bradycardia or with a family history of sudden infant death syndrome or long QT syndrome.2
Both short QT syndrome and long QT syndrome have been reported to cause sudden unexpected death in infancy.2,3 Our review did not address the indications for electrocardiography in infants with a family history of sudden cardiac death, but we agree that any baby with a family history of sudden unexpected death in infancy, sudden cardiac death, conduction defect or ventricular arrhythmia should undergo electrocardiography.
It was also outside the scope of our review to discuss recommendations for the clinical evaluation of infants who have experienced an apparent life-threatening event. In a recent review of the yield of diagnostic testing in 243 such infants, electrocardiography was considered to be indicated in only 25% of the cases and all of the electrocardiograms were normal.4 There have been 2 reported cases of infants who experienced an apparent life-threatening event attributed to long QT syndrome, and there is 1 reported case of an infant with Brugada syndrome who experienced an apparent life-threatening event associated with ventricular fibrillation, but his QT interval was normal.5,6 Hence, considering the rarity of apparent life-threatening events caused by long QT syndrome or short QT syndrome, there has not been any formal recommendation that all infants experiencing an apparent life-threatening event should have electrocardiography as part of the clinical evaluation following the event, except insofar as indicated by the baby's specific history and initial clinical evaluation. Although again this is outside the scope of our review, we would agree with this general approach.