Episodes of bradycardia during early infancy in the term-born and preterm infant
J. E. Hodgman, T. Hoppenbrouwers and L. A. Cabal
Division of Neonatology, Los Angeles County+University of Southern California Medical Center 90033.
OBJECTIVE--To document the incidence of transient episodes of bradycardia
in a group of healthy term and preterm infants during the first 1 to 6
months of life. DESIGN--Longitudinal polysomnographic study. SETTING--Sleep
laboratory in a university-affiliated urban medical center.
PARTICIPANTS--Fourteen healthy term-born infants, nine preterm infants with
apnea in the nursery, and 10 preterm infants without apnea. Infants with
neonatal morbidity except apnea were excluded. MEASUREMENTS--Transient
episodes of bradycardia (< or = 100 beats per minute) were identified in
2- to 4-hour early evening polysomnographic tracings. The relationship with
apnea, transcutaneous oxygen levels, and sleep state was determined.
RESULTS--Transient episodes of bradycardia to 60 to 70 beats per minute
were common, but there were no drops below 50 beats per minute. The
incidence of transient episodes of bradycardia was inversely related to
heart rate. Results for apneic and nonapneic premature infants were
similar. CONCLUSIONS--Transient episodes of bradycardia are considered
normal reflex responses and are not related to risk for sudden infant death
syndrome. These results have implications for the setting of monitor
alarms.
