Sudden infant death syndrome: clues from mice

Sudden infant death syndrome (SIDS) is a poorly understood cause of infant death during the first year of life. Risk factors for SIDS include a prone (face-down) sleeping position, respiratory disorders and prolongation of the QTc interval (a measure of the heart’s electrical activity). Given these risk factors, Neary et al. hypothesised that neonatal hypoxia leading to abnormal cardiac electrical conduction might cause SIDS. To test this hypothesis, the researchers non-invasively measured postnatal electrocardiogram (ECG) changes in normal and hypoxic conditions in newborn mice. Reduced oxygen was associated with ECG abnormalities and predisposed the mice to sudden death. This observation, together with existing data, support the researchers’ hypothesis, and suggest that hypoxia-prevention strategies, ECG screening and close monitoring of infants with a long QTc would prevent many sudden infant deaths. Page 503