Are some crib deaths sudden cardiac deaths?

Research performed during the past two decades suggests that crib deaths are biphasic phenomena: the infant victims are preconditioned in subtle ways before birth so that some of their most critical physiologic functions are subtly deficient. Then, at 2 to 4 months of age, when confronted by some challenge, such as a head cold, they are unable to overcome or adapt to the stress and die, seemingly without cause. It is likely that these deaths represent a heterogeneous group of pathogenetic phenomena rather than a single entity. Spontaneous idiopathic pathologic apnea, for example, may be responsible for 5 to 7% of crib deaths. Infant botulism may account for another 5%. A recent report on a prospective study of more than 5,000 babies showed that all 3 infants who ultimately succumbed to crib death had had abnormally prolonged corrected QT intervals on day 4 of life; the report contends that that irregularity leads to ventricular fibrillation, which is then the immediate cause of death. Although this work has not been confirmed and some take issue with the method, it now seems the most valid available body of data on the subject and suggests that some crib deaths, probably less than 10%, may be sudden cardiac deaths.