Asystoles during infancy recorded by home memory monitors. Benign events?
R. G. Meny, K. Currey, J. N. Scheel, D. Harrington and F. L. Vice
SIDS Institute, University of Maryland School of Medicine, Baltimore, USA.
OBJECTIVES: To assess the frequency and clinical significance of asystole
(sinus arrest > or = 2.0 seconds) and the incidence of bradycardia in
infants prescribed home cardiorespiratory monitors and to test the
hypothesis that asystoles are more likely to occur in preterm infants.
DESIGN: Prospective, consecutive sample of monitor printouts. METHODS: All
291 printouts from the memory monitors of 161 patients received during a
2-month period were analyzed. SETTING: University hospital providing
primary and referral care. MAIN OUTCOME MEASURES: Asystoles and
bradycardias; clinical course of patients with asystoles. RESULTS: Eight
patients (5.0%) had 32 episodes of asystole lasting 2.0 to 4.3 seconds
(group 1). Fifty-three patients (32.9%) had true bradycardia alarms but no
asystoles (group 2). One hundred patients (62.1%) had neither asystoles nor
bradycardias (group 3). Preterm infants constituted 88% of group 1 and 81%
of group 2 but only 58% of group 3. Infants were more likely to be
full-term in group 3 than in the other 2 groups (chi 2, P = .02). Birth
weights were lower in group 1 than in group 3 (P < .05, 1-tailed t
test). There were 479 true bradycardias; 72.2% lasted 10 seconds or less,
26.3% were longer than 10 seconds but no more than 20 seconds, and 1.5%
were longer than 20 seconds. None of the 8 patients with asystoles required
resuscitation for their asystoles; all survived and were free of any
life-threatening events after their monitors were discontinued and up until
their first birthday. CONCLUSIONS: Asystoles occur more commonly in preterm
infants; those pauses in the 2.0- to 4.0-second range seem to be benign.
Studies of long-term recordings are needed to redefine asystole in both
normal preterm and fullterm infants. These data would help further refine
current guidelines for pacemaker implantation during infancy.
