Prolonged apnea and cardiac arrhythmias in infants discharged from neonatal intensive care units: failure to predict an increased risk for sudden infant death syndrome.

Twenty-four hour recordings of respiratory wave form and ECG were made on low-birth-weight and/or premature infants within one week of discharge from eight neonatal intensive care units. Eight infants (0.7%) had episodes of apnea greater than 30 seconds in duration, all of which were accompanied by bradycardia less than 100 beats per minute; 25 infants (2.3%) had a total of 36 apneic episodes between 20 and 30 seconds in duration, 29 of which were accompanied by bradycardia less than or equal to 100 beats per minute; and 19 infants (1.7%) had episodes of bradycardia less than or equal to 50 beats per minute without prolonged apnea (as shown by a lack of breathing movement). Five infants had ventricular premature beats (including one with ventricular tachycardia). Eleven infants had supraventricular premature beats (including two with supraventricular tachycardia and one with preexcitation). Four infants had both supraventricular and ventricular premature beats. Two infants had preexcitation. Eleven infants who underwent 24-hour recordings died. Five infants were victims of sudden infant death syndrome. One infant death was sudden and unexpected and was attributed to bronchopneumonia. Two deaths were associated with congenital heart disease and three were associated with major cerebral disorders. None of the six babies who died suddenly and unexpectedly had apnea greater than or equal to 20 seconds, bradycardia less than or equal to 50 beats per minute, or cardiac arrhythmias on their 24-hour recordings.