Cardiac rhythm and conduction disorders in children remain a pressing issue in pediatric cardiology due to their prevalence, possible asymptomatic course, and risk of progression to severe complications. The aim of the study was to determine the clinical and instrumental features of bradyarrhythmia syndrome in children without organic heart disease.Data from 32 children aged 2 to 17 years who underwent inpatient examination for detected bradyarrhythmia were analyzed. Patients with congenital and acquired heart defects, cardiomyopathies, and myocarditis were excluded. Clinical and anamnestic data were evaluated, archived ECGs were analyzed, standard ECGs were performed, Holter ECG monitoring was performed to determine heart rate variability, and Doppler echocardiography was performed. 

Boys predominated in the study population (75.0 %), and most children were aged 11–14 years (40.6 %). In 78.1% of cases, bradyarrhythmia was detected during preventive examinations. A heart rate below the 2nd percentile was recorded in 59.4 % of children, and below the 5th percentile in 40.6 %. The most frequently diagnosed conditions were sinus bradycardia (43.7 %), sinoatrial block (21.8 %), sinus node dysfunction (12.5 %), first- and second-degree atrioventricular block (15.6 %), and binodal dysfunction (6.3 %). A burdened perinatal history was noted in 59.4 % of children, and a hereditary predisposition to cardiovascular pathology was noted in one-third. Extracardiac factors were often detected: pathology of the nasopharynx (21.9 %) and gastrointestinal tract (40.6 %), as well as signs of connective tissue dysplasia (59.4 %).Myocardial contractility was preserved in all patients, with a predominance of hyperkinetic hemodynamics. Two children had left ventricular dilatation, which correlated with the severity of bradyarrhythmia. The data obtained indicate a predominantly dysregulatory, vegetatively determined nature of bradyarrhythmias in children and the need for their comprehensive examination and dynamic observation for the purpose of early detection of possible progression of conduction disturbances. 

Tetiana Filonova has 30 years of professional experience in pediatric cardio rheumatology. She is an associate professor at the department of Pediatrics and Neonatology, Kharkiv National Medical University. She is the author of over 200 scientific publications.