DEVELOPMENTAL PATTERNS OF HEART-RATE AND VARIABILITY IN INFANTS WITH PERSISTENT APNEA OF INFANCY

During periods of regular breathing, heart rate is slower and more var iable in healthy (no history of respiratory distress syndrome) prematu rely born infants with persistent apnea, relative to full-term control infants of comparable post-conceptional ages. We tested the hypothesi s that the cardiovascular differences may be linked to the persistent apnea, rather than premature birth, by assessing heart rate and variab ility in full-term infants with persistent apnea. Thus, resting heart rate and variability were compared in full-term infants with apnea of infancy, prematurely born infants with persistent apnea, and full-term control infants. Full-term infants with persisting apnea showed slowe r heart rates than control infants, beginning at 4 months after birth, and enhanced heart rate variability beginning at 6 months. Healthy pr ematurely born infants with persistent apnea showed cardiovascular alt erations similar to those of full-term infants with apnea; these alter ations differed from those observed in very premature infants with his tories of respiratory distress. The postnatal development of cardiovas cular aberrations in infants with persistent apnea suggests that mecha nisms accompanying apneic events may contribute to long-term alteratio ns in autonomic control. (C) 1998 Elsevier Science Ireland Ltd.