Aaron Curns, MPH, Alfred Steinschneider, MD, PhD, Cheryl Richmond, MD, MPH
American SIDS Institute, 2480 Windy Hill Road, Suite 380, Marietta, GA 30067 USA
Phone:770-612-1030. Fax: 770-612-8277. Email: prevent@SIDS.org

A retrospective descriptive study was conducted to estimate the prevalence of bradycardia of varying durations in three groups of infants known to be at high risk for SIDS. Infants studied were: 1) siblings of SIDS victims (SibSIDS N=310), 2) ALTE=s at home (ALTE N=237), and 3) premature infants with a history of apnea or bradycardia (Premie Apnea N=281). Episodes were confirmed and measured from recorded waveforms obtained by a home apnea/bradycardia monitor. The initial low heart rate setting was 80 bpm. The setting was decreased when examination of the waveforms revealed that bradycardia alarms occurred due to respiratory sinus arrhythmia. A survival analysis was employed to accommodate the censoring of infants during the 112 day follow-up period due to inadequate monitor usage. Infants were less than 180 days postnatal age at study inception. The following bradycardia prevalence estimates were obtained.

The prevalence of bradycardia was significantly greater in the Premie Apnea group than for the SibSIDS and ALTE groups for bradycardia durations 5, 10, and 15 seconds in duration. There were no significant differences in bradycardia prevalence between the ALTE and SibSIDS groups.

*p< 0.05