Role of congenital long-QT syndrome in unexplained sudden infant death: proposal for an electrocardiographic screening in relatives.

INTRODUCTION: Congenital long-QT syndrome (LQTS) is a sporadic or familial inherited arrhythmia. It can lead to sudden death by ventricular fibrillation which occurs at any age but particularly during infancy. Recent studies of postmortem molecular analysis in infants who died of unexplained sudden infant death syndrome (SIDS) showed abnormal mutations to LQTS in 10% to 12%. Current methods of etiologic investigation of sudden infant death syndrome do not allow the diagnosis of LQTS. A targeted anamnesis together with systematic electrocardiograms of first- and second-degree relatives could be an efficient LQTS diagnostic tool. Therefore, we propose to include them in screening procedures for SIDS etiologies.

CONCLUSION: LQTS accounts for a significant number of unexplained SIDS. We suggest adding a systematic familial electrocardiographic screening to the current etiologic investigations in order to track congenital LQTS in relatives.