A Prospective Evaluation of Arrhythmias in a Large Tertiary Neonatal Intensive Care Unit

Introduction: Arrhythmias in the neonatal period are common and can be classified as bradyarhythmias and tachyarrhythmias and as benign or non-benign. Neonatal arrhythmias are further differentiated between those with abnormalities in generation (non-sinus) and those with abnormalities in propagation. Because the neonatal myocardium is immature and operates at the peak of the Starling curve, significant changes in heart rate can result in a decline in cardiac output and compromise end-organ perfusion. This is especially true for premature neonates, those critically ill, or those with concomitant congenital heart disease. While sustained arrhythmias are frequently witnessed and recorded in tertiary neonatal intensive care units (NICU) very little data exists on the observance of non-sustained brady or tachyarrhythmias in this cohort. No prospective study has been performed on all neonates admitted to a large tertiary NICU throughout their entire stay. The purpose of this study was to prospectively evaluate the prevalence and type of arrhythmias in a large NICU population from admission to discharge. Methods: All neonates admitted to the NICU at Inova Children’s Hospital at Inova Fairfax Medical Campus between January 1, 2021 and April 1, 2021 were prospectively evaluated from admission to hospital discharge via continuous bedside monitoring reviewed every 24 hours. Concerning telemetry strips were reviewed by two team members as well as the senior electrophysiologist. Results: Two-hundred and one neonates (mean gestational age = 344/7 weeks’) were enrolled in the study. Admission length ranged from 1 to 195 days (total of 5624 patient days, median 16 days). Overall, 68% (N = 137) of admissions had one or more arrhythmias, the most common of which was sinus tachycardia (65%, N = 130), followed by sinus bradycardia (30%, N = 60). Clinically relevant arrhythmias were diagnosed in 6.5% of neonates. During the study period there were four deaths, none of which were directly attributable to a primary arrhythmia. Conclusion: Approximately 68% of neonates exhibited at least one arrhythmia. Although the vast majority of these arrhythmias were benign, clinically relevant arrhythmias were observed in 6.5%. Patients admitted to the NICU appear to have a relatively high burden of benign arrhythmias, but a relatively low burden of pathologic arrhythmias.