Affiliations: Division of Neonatology, Department of Pediatrics, Medical College of Georgia, Georgia Health Sciences University, Augusta, GA, USA
Note:  Corresponding author: Oommen P. Mathew, Section of Neonatology, Medical College of Georgia Georgia Health Sciences University, 1120 15th street, BIW 6033, Augusta, GA 30912-3740, USA. Tel.: +1 706 721 2331; E-mail: [email protected]
Abstract: Objective: The primary aim of this study was to determine whether the incidence of bradyarrhythmias in preterm infants decreases with maturation. Study design: Cardiorespiratory waveforms in preterm infants with gestational age ≤ 32 weeks were acquired on a networked computer after they were weaned to room air or to supplemental oxygen through a nasal cannula. Waveforms for 24 hours were screened for bradycardia utilizing Neoscan® software. Bradyarrhythmias were classified as non-sinus atrial, junctional, ventricular, and other. Results: Sixteen preterm infants were evaluated longitudinally. Their mean birth weight and gestational age were 1030 ± 232g and 28.2 ± 2.2 weeks, respectively. These infants were evaluated initially at a mean postmenstrual age (PMA) of 31 ± 1.2 weeks. Mean number of bradycardia episodes was 1.25 ± 0.95 per hour; of these 0.73 ± 0.78 had bradyarrhythmias. These infants were subsequently evaluated at a mean PMA of 34.4 ± 2.0 weeks. Mean number of bradycardia episodes had decreased to 0.85 ± 0.79 per hour (P < 0.05). Furthermore, the number of bradyarrhythmias decreased significantly to 0.33 ± 0.37 per hour (P < 0.05). This decrease was also significant when expressed as a ratio of arrhythmia episodes to total bradycardia episodes (P < 0.05). The vast majority of bradyarrhythmias were non-sinus atrial rhythm; junctional rhythm accounted for the remaining. Nine infants exhibited more than one type of arrhythmia. Conclusion: Non-sinus bradyarrhythmias occur frequently in preterm infants and its incidence decreases with postnatal maturation.