Prevalence of bradyarrhythmias during transient episodes of bradycardia among preterm infants

Objective: The primary aim of this study was to determine the prevalence of transient bradyarrhythmias in preterm infants. The secondary aim was to characterize the non-sinus atrial rhythm. Study design: Cardiorespiratory waveforms in preterm infants with gestational age ⩽ 32 weeks were acquired on a networked computer. Waveforms for 24 hours were screened for bradycardia utilizing Neoscan® software. Each bradycardia event was further reviewed for arrhythmia and classified as non-sinus atrial, junctional, ventricular, and others. Results: Among the 58 preterm infants studied, 5 showed no transient bradycardia, 9 showed only sinus bradycardia and 44 exhibited both sinus and non-sinus bradyarrhythmias. Of the bradyarrhythmia episodes evaluated (n=546), the majority were classified as non-sinus atrial rhythm (54.2%); junctional (32.3%), ventricular (1.1%) and others (12.5%) constituted the remaining. Decreases in P-wave amplitude and PR interval were observed in the majority of non-sinus atrial bradycardia episodes. More than one type of arrhythmia was seen in most infants. Conclusion: Non-sinus bradyarrhythmias occur frequently in preterm infants during transient bradycardia episodes.