Abnormal polygraphic findings in near-miss sudden infant death.

Sleep, respiratory, and cardiac data obtained during sleep and wakefulness by continuous 24-hour polygraphic monitoring from twelve infants who were "near misses" for the sudden-infant-death syndrome were compared with similar information obtained from seven low-risk infants. Although the sleep variables studied were of limited value in differentiating between the low and high risk patients, respiratory and cardiac abnormalities were strikingly more common in near-miss infants. High-risk infants demonstrated both obstructive and mixed stopped-breathing episodes (S.B.E.). Bradycardia was seen secondary to S.B.E. but also simultaneously with or independent of S.B.E. Sudden asystole associated with S.B.E. was seen in one case. These results suggest an autonomic-nervous-system dysfunction in high-risk infants.