Significant Cardiac Rhythm Disturbances in Infant Bronchiolitis: A Holter-Based Prospective Analysis

Bronchiolitis is a major cause of respiratory illness in infants. Few studies have demonstrated arrhythmias during bronchiolitis, including bradycardia and atrioventricular block, some requiring pacemaker implantation. However, the association between bronchiolitis and cardiac arrhythmias remains unclear. In this work we sought to investigate the incidence and characteristics of arrhythmias during bronchiolitis in infants younger than 1 year of age.

A single-center, prospective cohort study was conducted on infants hospitalized with a clinical diagnosis of bronchiolitis. Demographic and clinical data were collected via questionnaire. All infants underwent overnight Holter monitoring during hospitalization.

Among 100 enrolled infants (79% positive for respiratory syncytial virus), 18 (18%) demonstrated arrhythmias: sinus arrest (2-13 seconds) in 8 infants, bradycardia <60 bpm in 7 infants, and frequent atrial premature complexes (3%-18% of beats) in 3 infants. Follow-up Holter recordings in 7 patients (38%) showed resolution of arrhythmias within 1-4 months. No significant demographic or clinical predictors were identified. None of the infants exhibited symptoms (eg, cyanosis, unresponsiveness) associated with arrhythmia severity.

Our study shows that bronchiolitis is associated with significant arrhythmias in infants, particularly sinus arrest, bradycardia, and atrial premature complexes. In our cohort, none of the infants with significant arrhythmia required arrhythmia intervention. Clinicians should be aware of this association and consider delaying decisions regarding pacemaker implantation until after the resolution of bronchiolitis even in cases of infants with severe bradycardia. Future investigations should explore the pathophysiology and prognostic implications of this phenomenon.