Sudden infant death syndrome and prolongation of the QT interval
A. Steinschneider
A standard lead II ECG was recorded during either the first or the fourth
week of life or at both ages from 30 neonates whose sibling had died of the
sudden infant death syndrome (SIDS). Electrocardiographic recordings also
were obtained from 75 control neonates and from 52 adults who had had an
infant who died of SIDS. The neonatal data revealed that the QT interval,
corrected for heart rate (QTC), was longest during NREM (vs rapid eye
movement [REM]) sleep. Furthermore, the QTC interval was longer within the
fourth week than in the first week of life. However, the QTC interval of
siblings of SIDS victims did not differ from that of the control infants,
nor did the QT interval of parents of SIDS victims differ from published
normal values. One neonate who subsequently died of SIDS did not have an
abnormally long QTC interval. These data do not support the hypothesis that
genetically determined prolongation of the QT interval plays a major role
in SIDS.
