Distinguishing left ventricular hypertrophy from hypertrophic cardiomyopathy in adolescents - a longitudinal observation study

Eur J Prev Cardiol. 2023 Nov 22:zwad361. doi: 10.1093/eurjpc/zwad361. Online ahead of print.

Abstract

Aims: Echocardiographic characteristics to distinguish physiological left ventricular (LV) hypertrophy from pathology is warranted in early adolescent athletes. This study aimed to explore the phenotype, progression and potential grey zone of LV hypertrophy during adolescence in athletes and hypertrophic cardiomyopathy (HCM) genotype positive patients.

Methods: In this longitudinal observation study, we compared 76 12-year-old athletes to 55 age- and sex-matched HCM genotype positive patients. Echocardiographic parameters were evaluated by paediatric reference values (Z-scores). HCM genotype positive patients were included if they had no or mild LV hypertrophy (maximum wall thickness <13 mm, Z-score <6 for interventricular septum diameter (IVSd) or posterior wall thickness). We collected clinical data, including cardiac events.

Results: Mean follow-up-time was 3.2 ± 0.8 years. At baseline, LV hypertrophy was found in 28% of athletes and 21% of HCM genotype positive patients (p = 0.42). Septum thickness was similar (ZIVSd 1.4 ± 0.9 vs 1.0 ± 1.3, p = 0.08), and increased only in HCM genotype positive patients (ZIVSd progression rate -0.17(SE0.05), p = 0.002 vs 0.30(SE0.10), p = 0.001). LV volumes were greater in athletes (ZLVEDV 1.0 ± 0.6 vs -0.1 ± 0.8, p < 0.001, ZLVEDV progression rate -0.05(SE0.04), p = 0.21 vs -0.06(SE0.04), p = 0.12). Cardiac arrest occurred in two HCM genotype positive patients (age 13 and 14), with ZIVSd 8.2-11.5.

Conclusions: LV hypertrophy was found in a similar proportion in early adolescence, but progressed only in HCM genotype positive patients. A potential grey zone of LV hypertrophy ranged from septum thickness Z-score 2.0-3.3. LV volumes remained larger in athletes. Evaluating progression of wall thickness and volume may help clinicians distinguish physiological LV hypertrophy from early HCM.

Keywords: Athlete; adolescent; cardiac remodelling; echocardiography; exercise; hypertrophic cardiomyopathy; left ventricular hypertrophy.

Plain language summary

Exercise-induced cardiac left ventricular (LV) hypertrophy is important to distinguish from hypertrophic cardiomyopathy (HCM), because athletes with HCM may have an increased risk of sudden cardiac death. Limited data exist on this distinction in adolescent athletes. Therefore, we performed a longitudinal observation study comparing development of LV hypertrophy during adolescence in athletes and HCM genotype positive patients. In early adolescence, LV hypertrophy was found in a similar proportion of athletes and HCM genotype positive patients, with a potential grey zone ranging from septum thickness Z-score 2.0-3.3. After three years follow-up, LV hypertrophy had only progressed in HCM genotype positive patients, while athletes had larger left ventricular volumes throughout the study period. Evaluation of LV volume and septum thickness progression may assist doctors in distinguishing exercise-induced LV hypertrophy from early HCM disease in adolescents.