Clinical case: complete atrioventricular block in a young child

Cardiac conduction disorder is one of the most complex challenges in pediatric cardiology. In young children, the most important issue is the presence of atrioventricular (AV) block, which manifests as an abnormal slowing (incomplete block) or cessation (complete block) of electrical impulse conduction from the atria to the ventricles. The most severe form is complete AV block, which requires urgent diagnosis and, as a rule, implantation of a permanent pacemaker (PM). The aim of this study is to present a clinical case of complete AV block in a young child. A retrospective analysis of the patient’s medical history was performed; the patient was under follow-up and treatment in the cardiovascular surgery department. At the age of 2 years and 11 months, during a routine medical examination, ECG revealed cardiac rhythm disturbances manifested as sinus arrhythmia, heart rate of 50 bpm, and AV block. Due to suspected of complete AV block, the patient was urgently hospitalized for further examination and treatment. Comprehensive laboratory and instrumental examination of the child revealed complete AV block along with signs of heart failure. Based on clinical indications, the girl underwent permanent pacemaker implantation surgery with subsequent dynamic monitoring. During follow-up ECG monitoring, the primary rhythm was registered as IC in DDD mode, predominantly atrial-synchronized mode (pacemaker rhythm percentage 99 %). Five months post-implantation, during a follow-up examination, the ECG revealed ventricularpaced rhythm with a heart rate of 100 beats per minute. After two years, 24-hour ECG monitoring revealed a pacemaker rhythm in DDD mode with a baseline ventricular stimulation rate of 70–145 impulses per minute. The spontaneous rhythm was sinus. Pacemaker rhythm percentage reached 99 %. Echocardiographic findings showed no chamber enlargement, with a left ventricular ejection fraction of 70 %. This clinical case of complete AV block in a young child serves to draw attention of pediatricians, pediatric cardiologists, and specialists to the particularities of clinical presentation, diagnosis, and management of this rare pathology.

1. Balykova L.A., Vladimirov D.O., Krasnopolskaya A.V., et al. Cardiovascular system damage in children with COVID-19. Pediatria n.a. G.N. Speransky. 2021;100(5):90–98 (in Russian). https://doi.org/10.24110/0031-403X-2021-100-5-90-98.

2. Kovalev I.A., Belozerov Yu.M., Sadykova D.I., et al. Atrioventricular block in children. Pediatric Pharmacology. 2018;15(5):365–375 (in Russian). https://doi.org/10.15690/pf.v15i5.1959.

3. Krutova A.V., Kotlukova N.P., Simonova L.V., et al. The course and prognosis of cardiac rhythm and conduction disorders in children of the first year of life. Pediatria n.a. G.N. Speransky. 2015;94(2):13–18 (in Russian).

4. Loginova M.S., Bregel L.V., Subbotin V.M., et al. Heart injury in infants with cytomegalovirus infection. Siberian Medical Journal. 2012;110(3):79–81 (in Russian).

5. Malkina E.V., Kvetnaya A.S., Egorov D.F. Clinical case of binodal dysfunction against the background of chronic herpetic infection. Medicine of Extreme Situations. 2018;20(3):305–309 (in Russian).

6. Polyakova E.B., Kulbachinskaya E.K., Termosesov S.A., et al. Thoracoscopic implantation of an epicardial pacemaker in a child with complete atrioventricular block. Journal of Arrhythmology. 2019;26(2):58–61 (in Russian). https://doi.org/10.35336/VA-2019-2-58-61.

7. Polyakova E.B., Trofimova T.A., Shkolnikova M.A. Cardiac rhythm and conduction disturbances in children with bradyarrhythmias during long-term ECG monitoring. Medical Alphabet. 2024;(30):21–27 (in Russian). https://doi.org/10.33667/2078-5631-2024-30-21-27.

8. Ponomareva D.A., Nagaeva T.A., Zhelev V.A., et al. Cardiac manifestations of post-COVID syndrome in children and adolescents. Siberian Medical Review. 2022;(5):81–85 (in Russian). https://doi.org/10.2333/25000-136-2022-5-81-85.

9. Shkolnikova M.A. Pediatric arrhythmology is an important direction of pediatric cardiology. Journal of Arrhythmology. 2021;28(4):5–8 (in Russian). https://doi.org/10.35336/VA-2021-4-5-8.

10. Antzelevitch C. Molecular genetics of arrhythmias and cardiovascular conditions associated with arrhythmias. PACE. 2007;26:2194–2208.

11. Baruteau A.E., Fouchard S., Behaghel A., et al. Characteristics and long-term outcome of non-immune isolated atrioventricular block diagnosed in utero or early childhood: a multicentre study. Eur Heart J. 2011;33(5):622–629. https://doi.org/10.1093/eurheartj/ehr347.

12. Schwartz P.J. 1970–2020: 50 years of research on the long QT syndrome – from almost zero knowledge to precision medicine. Eur Heart J. 2021;42(11):1063–1072. https://doi.org/10.1093/eurheartj/ehaa769.

13. Steinberg L. Congenital heart block. Cardiol Clin. 2023;41(3):399–410. https://doi.org/10.1016/j.ccl.2023.03.002.