Cardiac rhythm and conduction disturbances in children with bradyarrhythmias during long-term ECG monitoring

The syncope in children with bradyarrhythmias can be life-threatening and their differentiation is important in the evaluation of any child with syncope. In children risk factors for the poor prognosis and progression of bradyarrhythmias leading to the development of arrhythmogenic syncope have not been definitively determined. The aim was to determine the diagnostic significance of the implantable cardiac monitors (ICM) method and identify electrocardiographic and electrophysiological predictors of the development of syncope in children with bradyarrhythmias. Material and methods. The authors analyze the group of 191 children with bradyarrhythmias, recurrent syncope and ICM. The examination of patients included electrocardiography (ECG), echocardiography (ECHO-CG), Holter monitoring (HM) of rhythm, electrophysiological study (EHS), exercise test, and analysis of family anamnesis data. Results. 96 out of 191 children had positive result of long-term cardiac monitoring. 16 out of 96 children had structural heart deseases – congenital heart defects, cardiomyopathies. Episodes of arrhythmias were documented in 30% of children during syncope and asymptomatic arrhythmias were observed in 43% of children. Arrhythmogenic syncope accounts for 7,5% of all registered syncope and 5% of positive monitoring results. Sinus rhythm during syncope was registered in 48% of children, and 2% of patients had a combination of arrhythmogenic and non-arrhythmogenic syncope. The heart rhythm characteristics of standard ECG and HM in patients with symptomatic arrhythmias did not differ significantly from either patients with asymptomatic episodes of arrhythmias or patients with sinus rhythm during syncope. Conclusion. The diagnostic significance of the ICM for identifying the cause of recurrent syncope in children with bradyarrhythmias is 50%. Arrhythmogenic genesis of syncope has been confirmed in 7.5% of children with bradyarrhythmias. The heart rate characteristics and electrophysiological parameters of the previous examination are not predictors of the development of syncope in children with bradyarrhythmias. Long-term cardiac monitoring of ICM can identify children with life-threatening arrhythmogenic syncope from all patients with bradyarrhythmia and make the prevention of sudden cardiac death (SCD).