Rhythm and conduction disorders in children with hypertrophic cardiomyopathy

Rhythm and conduction disorders remain key determinants of prognosis in hypertrophic cardiomyopathy.

Objective. To assess the nature, frequency, and clinical-prognostic significance of cardiac rhythm and conduction disorders in children with hypertrophic cardiomyopathy.

Materials and Methods. This retrospective-prospective study included 200 children with confirmed primary hypertrophic cardiomyopathy (median age 14.34 years; 2/3 male). Median follow-up was 5.74 years. Life-threatening arrhythmias were defined as sudden cardiac death, aborted sudden cardiac death, or appropriate implantable cardioverter-defibrillator therapy.

Results. Rhythm and conduction disorders were detected in 77 % of children. Ventricular extrasystole ≥ 10/24h was observed in 25.5 %, and non-sustained ventricular tachycardia in 20.5 %. Life-threatening arrhythmias occurred in 27 children (13.5 %): sudden cardiac death (n = 6), aborted sudden cardiac death (n = 11), and appropriate implantable cardioverter-defibrillator shocks for primary prevention (n = 10). Ventricular extrasystole 10–500/24h (OR 4.93; p = 0.00002) and ventricular extrasystole ≥ 500/24h (OR 6.84; p = 0.015) were associated with non-sustained ventricular tachycardia. Extreme myocardial hypertrophy increased the odds of non-sustained ventricular tachycardia 2.3-fold (p = 0.018). Sick sinus syndrome was diagnosed in 10.5 % of children and was a strong predictor of life-threatening arrhythmias (OR 5.18; p<0.001). Intraventricular conduction disturbances were noted in 54.5 %, first-degree atrioventricular block in 20 %, and supraventricular tachyarrhythmias in 5.5 %.

Conclusion. Hypertrophic cardiomyopathy is characterized by a high prevalence of rhythm and conduction disorders. Even moderate ventricular extrasystole is associated with non-sustained ventricular tachycardia, justifying routine Holter monitoring in all children with hypertrophic cardiomyopathy. Sick sinus syndrome is associated with a fivefold increased risk of life-threatening arrhythmias and should be incorporated into sudden cardiac death risk stratification algorithms. Such patients may warrant a lower 5-year sudden cardiac death risk threshold for dual-chamber cardioverter-defibrillator implantation.

1. Elliott P.M., Anastasakis A., Borger M.A., Borggrefe M., Cecchi F., et al. 2014 ESC Guidelines on diagnosis and management of hypertrophic cardiomyopathy: the Task Force for the Diagnosis and Management of Hypertrophic Cardiomyopathy of the European Society of Cardiology (ESC). Eur Heart J. 2014;35(39):2733-2779. DOI: 10.1093/eurheartj/ehu284

2. Ommen S. R., Mital S., Burke M.A., Day S.M., Deswal A., Elliott P., et al. 2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy: Executive Summary: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. Circulation. 2020;142(25):e533-e557. DOI: 10.1161/CIR.0000000000000938

3. Aggarwal K., Boyapati S.P., Valecha J., Noor A., Kanwal F., Jain R., et al. Arrhythmias and Hypertrophic Cardiomyopathy: Unravelling the Connection. Curr Cardiol Rev. 2024;20(4):e240124226139. DOI: 10.2174/011573403X279223231227111737

4. Norrish G., Cantarutti N., Pissaridou E., Ridout D.A., Limongelli G., Elliott P.M., et al. Risk factors for sudden cardiac death in childhood hypertrophic cardiomyopathy: A systematic review and meta-analysis. Eur J Prev Cardiol. 2017;24(11):12201230. DOI: 10.1177/2047487317702519

5. Arbelo E., Protonotarios A., Gimeno J. R., Arbustini E., Barriales-Villa R., Basso C., et al. 2023 ESC Guidelines for the management of cardiomyopathies. Eur Heart J. 2023;44(37):35033626. DOI: 10.1093/eurheartj/ehad194

6. Maron B.J., Rowin E.J., Casey S.A., Lesser J.R., Garberich R.F., McGriff D.M., et al. Hypertrophic Cardiomyopathy in Children, Adolescents, and Young Adults Associated With Low Cardiovascular Mortality With Contemporary Management Strategies. Circulation. 2016;133(1):62-73. DOI: 10.1161/CIRCULATIONAHA.115.017633

7. Perez-Alday E.A., Haq K.T., German D.M., Hamilton C., Johnson K., Phan F., et al. Mechanisms of Arrhythmogenicity in Hypertrophic Cardiomyopathy: Insight From Non-invasive Electrocardiographic Imaging. Front Physiol. 2020;11:344. DOI: 10.3389/fphys.2020.00344

8. Cecchi F., Sgalambro A., Baldi M., Sotgia B., Antoniucci D., Camici P.G, et al. Microvascular dysfunction, myocardial ischemia, and progression to heart failure in patients with hypertrophic cardiomyopathy. J Cardiovasc Transl Res. 2009;2(2):157-164. DOI: 10.1007/s12265-009-9102-5

9. Arsenos P., Gatzoulis K. A., Tsiachris D., Dilaveris P., Sideris S., Sotiropoulos I., et al. Arrhythmic risk stratification in ischemic, non-ischemic and hypertrophic cardiomyopathy: A two-step multifactorial, electrophysiology study inclusive approach. World J Cardiol. 2022;14(3):139-151. DOI: 10.4330/wjc.v14.i3.139

10. Zeppenfeld K., Tfelt-Hansen J., de Riva M., Winkel B.G., Behr E.R., Blom N.A., et al. 2022 ESC Guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death. Eur Heart J. 2022;43(40):3997-4126. DOI: 10.1093/eurheartj/ehac262

11. Siontis K.C., Geske J.B., Ong K., Nishimura R.A., Ommen S.R., Gersh B.J. Atrial fibrillation in hypertrophic cardiomyopathy: prevalence, clinical correlations, and mortality in a large high-risk population. J Am Heart Assoc. 2014;3(3):e001002. DOI: 10.1161/JAHA.114.001002

12. Spirito P., Autore C., Rapezzi C., Bernabò P., Badagliacca R., Maron M.S., et al. Syncope and risk of sudden death in hypertrophic cardiomyopathy. Circulation. 2009;119(13):17031710. DOI: 10.1161/CIRCULATIONAHA.108.798314

13. Magri D., Agostoni P., Sinagra G., Re F., Correale M., Limongelli G., et al. Clinical and prognostic impact of chronotropic incompetence in patients with hypertrophic cardiomyopathy. Int J Cardiol. 2018;271:125-131. DOI: 10.1016/j.ijcard.2018.04.019

14. Zhang H.D., Tang M., Zhang J.T. Characteristics of Primary Bradyarrhythmia in Hypertrophic Cardiomyopathy: A 10-Year, Single-Center Analysis. J Cardiovasc Dev Dis. 2022;9(11):370. DOI: 10.3390/jcdd9110370

15. Nandi D., Hayes E.A., Wang Y., Jerrell J.M. Epidemiology of Pediatric Hypertrophic Cardiomyopathy in a 10-Year Medicaid Cohort. Pediatr Cardiol. 2021;42(1):210-214. DOI: 10.1007/s00246-020-02472-2

16. O’Mahony C., Jichi F., Pavlou M., Monserrat L., Anastasakis A., Rapezzi C., et al. A novel clinical risk prediction model for sudden cardiac death in hypertrophic cardiomyopathy (HCM risk-SCD). Eur Heart J. 2014;35(30):2010-2020. DOI: 10.1093/eurheartj/eht439

17. Norrish G., Cleary A., Field E., Cervi E., Boleti O., Ziółkowska L., et al. Clinical Features and Natural History of Preadolescent Nonsyndromic Hypertrophic Cardiomyopathy. J Am Coll Cardiol. 2022;79(20):1986-1997. DOI: 10.1016/j.jacc.2022.03.347

18. Maron B. J., Spirito P., Ackerman M. J., Casey S. A., Semsarian C., Estes N. A., et al. Prevention of sudden cardiac death with implantable cardioverter-defibrillators in children and adolescents with hypertrophic cardiomyopathy. J Am Coll Cardiol. 2013;61(14):1527-1535. DOI: 10.1016/j.jacc.2013.01.037

19. Norrish G., Ding T., Field E., Ziółkowska L., Olivotto I., Limongelli G., et al. Development of a Novel Risk Prediction Model for Sudden Cardiac Death in Childhood Hypertrophic Cardiomyopathy (HCM Risk-Kids). JAMA Cardiol. 2019;4(9):918927. DOI: 10.1001/jamacardio.2019.2861

20. Marston N.A., Han L., Olivotto I., Day S.M., Ashley E.A., Michels M., et al. Clinical characteristics and outcomes in childhood-onset hypertrophic cardiomyopathy. Eur Heart J. 2021;42(20):1988-1996. DOI: 10.1093/eurheartj/ehab148

21. Colan S.D., Lipshultz S.E., Lowe A.M., Sleeper L.A., Messere J., Cox G.F., et al. Epidemiology and cause-specific outcome of hypertrophic cardiomyopathy in children: findings from the Pediatric Cardiomyopathy Registry. Circulation. 2007;115(6):773-781. DOI: 10.1161/CIRCULATIONAHA.106.621185

22. Conway J., Min S., Villa C., Weintraub R.G., Nakano S., Godown J., et al. The Prevalence and Association of Exercise Test Abnormalities With Sudden Cardiac Death and Transplant-Free Survival in Childhood Hypertrophic Cardiomyopathy. Circulation. 2023;147(9):718-727. DOI: 10.1161/CIRCULATIONAHA.122.062699

23. Norrish G., Cantarutti N., Pissaridou E., Ridout D.A., Limongelli G., Elliott P.M., et al. Risk factors for sudden cardiac death in childhood hypertrophic cardiomyopathy: A systematic review and meta-analysis. Eur J Prev Cardiol. 2017;24(11):12201230. DOI: 10.1177/2047487317702519

24. Miron A., Lafreniere-Roula M., Steve Fan C.P., Armstrong K.R., Dragulescu A., Papaz T., et al. A Validated Model for Sudden Cardiac Death Risk Prediction in Pediatric Hypertrophic Cardiomyopathy. Circulation. 2020;142(3):217-229. DOI: 10.1161/CIRCULATIONAHA.120.047235

25. Czosek R. J., Jefferies J. L., Khoury P. R., Anderson J. B., Wilmot I., Knilans T. K., et al. Arrhythmic Burden and Ambulatory Monitoring of Pediatric Patients with Cardiomyopathy. Pacing Clin Electrophysiol. 2016;39(5):443-451. DOI: 10.1111/ pace.12835

26. López Blázquez M., Espinosa Castro M. Á., Álvarez GarcíaRovés R., Centeno Jiménez M., Fernández Ávila A. I., Bermejo Thomas F. J., et al. Prognostic role of novel variables in sudden cardiac death risk associated to hypertrophic cardiomyopathy. An Pediatr (Engl Ed). 2025;102(4):503814. DOI: 10.1016/j.anpede.2025.503814

27. Ziółkowska L., Mazurkiewicz Ł., Petryka J., Kowalczyk-Domagała M., Boruc A., Bieganowska K., et al. The Indices of Cardiovascular Magnetic Resonance Derived Atrial Dynamics May Improve the Contemporary Risk Stratification Algorithms in Children with Hypertrophic Cardiomyopathy. J Clin Med. 2021;10(4):650. DOI: 10.3390/jcm10040650

28. Wang W., Lian Z., Rowin E.J., Maron B.J., Maron M.S., Link M.S. Prognostic Implications of Nonsustained Ventricular Tachycardia in High-Risk Patients With Hypertrophic Cardiomyopathy. Circ Arrhythm Electrophysiol. 2017;10(3):e004604. DOI: 10.1161/CIRCEP.116.004604

29. Wilkin M., Khraiche D., Panaioli E., Pontailler M., Raisky O., Marijon E., et al. Independent External Evaluation of Pediatric Hypertrophic Cardiomyopathy Risk Scores in Predicting Severe Ventricular Arrhythmias. Circ Arrhythm Electrophysiol. 2025;18(3):e012932. DOI: 10.1161/CIRCEP.124.012932

30. Yetman A.T., Hamilton R.M., Benson L.N., McCrindle B.W. Long-term outcome and prognostic determinants in children with hypertrophic cardiomyopathy. J Am Coll Cardiol. 1998;32(7):1941-1948

31. McKenna W.J., Franklin R.C., Nihoyannopoulos P., Robinson K.C., Deanfield J.E. Arrhythmia and prognosis in infants, children and adolescents with hypertrophic cardiomyopathy. J Am Coll Cardiol. 1988;11(1):147-153. DOI: 10.1016/07351097(88)90181-7

32. Bobkowski W., Sobieszczańska M., Turska-Kmieć A., Nowak A., Jagielski J., Gonerska M., et al. Mutation of the MYH7 gene in a child with hypertrophic cardiomyopathy and Wolff-Parkinson-White syndrome. J Appl Genet. 2007;48(2):185-188. DOI: 10.1007/BF03194677

33. Medscape. Hypertrophic Cardiomyopathy Clinical Presentation. Updated Aug 14, 2024. — https://emedicine.medscape.com/article/152913-clinical/Ссылка активна на: 06.07.2026

34. Khokhlov L., Hussain F., Ali M., Mena A., Rahima M.K., Kishore S., et al. Burden of arrhythmias in patients with hypertrophic cardiomyopathy, nation-wide study. J Card Fail. 2024;30(1):193. DOI: 10.1016/j.cardfail.2023.10.187

35. Liu J., Xu L., Wu X., Zhang M., Jiang W., Kang L., et al. Implications of primary bradycardia in patients with hypertrophic cardiomyopathy. Heart Rhythm. 2025;22(11):2917-2923. DOI: 10.1016/j.hrthm.2024.12.006

36. Marshall M., Malik A., Shah M., Fish F. A., Etheridge S. P., Aziz P. F., et al. Patterns of Electrocardiographic Abnormalities in Children with Hypertrophic Cardiomyopathy. Pediatr Cardiol. 2024;45(8):1692-1701. DOI: 10.1007/s00246-02303252-4

37. Hamidi J., Winter J., Weber R., Dittmann S., Schulze-Bahr E. Case Report: Hypertrophic cardiomyopathy with recurrent episodes of ventricular fibrillation and concurrent sinus arrest. Front Cardiovasc Med. 2023;10:1240189. DOI: 10.3389/fcvm.2023.1240189