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

AIMS: Echocardiographic characteristics to distinguish physiological left ventricular (LV) hypertrophy from pathology are 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 AND RESULTS: In this longitudinal observation study, we compared seventy-six 12-year-old athletes with 55 age-matched and sex-matched HCM genotype-positive patients. Echocardiographic parameters were evaluated by using paediatric reference values (Z-scores). Hypertrophic cardiomyopathy 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 (ZIVSd), or posterior wall thickness]. We collected clinical data, including data on cardiac events. The 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 values were 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 [standard error (SE) 0.05], P = 0.002 vs. 0.30 [SE 0.10], P = 0.001}. Left ventricular volume Z-scores (ZLVEDV) were greater in athletes [ZLVEDV 1.0 ± 0.6 vs. -0.1 ± 0.8, P < 0.001; ZLVEDV progression rate -0.05 (SE 0.04), P = 0.21 vs. -0.06 (SE 0.04), P = 0.12]. Cardiac arrest occurred in two HCM genotype-positive patients (ages 13 and 14), with ZIVSd 8.2-11.5. CONCLUSION: Left ventricular 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 a septum thickness Z-score of 2.0 to 3.3. Left ventricular volumes remained larger in athletes. Evaluating the progression of wall thickness and volume may help clinicians distinguish physiological LV hypertrophy from early HCM.

It is important to distinguish exercise-induced cardiac left ventricular (LV) hypertrophy from hypertrophic cardiomyopathy (HCM), because athletes with HCM may have an increased risk of sudden cardiac death. Limited data are available on this distinction in adolescent athletes. Therefore, we performed a longitudinal observation study comparing the development of LV hypertrophy during adolescence in athletes and HCM genotype­positive patients. In early adolescence, LV hypertrophy was found in a similar proportion of athletes and HCM genotype­positive patients, with a potential grey zone ranging from a septum thickness Z-score of 2.0 to 3.3. After 3 years of follow-up, LV hypertrophy had progressed only in HCM genotype­positive patients, while athletes had larger LV volumes throughout the study period.Evaluation of LV volume and septum thickness progression may assist clinicians in distinguishing exercise-induced LV hypertrophy from early HCM disease in adolescents.

Geometry as a Confounder When Assessing Ventricular Systolic Function: Comparison Between Ejection Fraction and Strain.

BACKGROUND: Preserved left ventricular (LV) ejection fraction (EF) and reduced myocardial strain are reported in patients with hypertrophic cardiomyopathy, ischemic heart disease, diabetes mellitus, and more. OBJECTIVES: The authors performed a combined mathematical and echocardiographic study to understand the inconsistencies between EF and strains. METHODS: An analytical equation showing the relationship between EF and the 4 parameters, global longitudinal strain (GLS), global circumferential strain (GCS), wall thickness, and short-axis diameter, was derived from an elliptical LV model. The equation was validated by measuring the 4 parameters by echocardiography in 100 subjects with EF ranging from 16% to 72% and comparing model-predicted EF with measured EF. The effect of the different parameters on EF was explored in the model and compared with findings in the patients. RESULTS: Calculated EF had very good agreement with measured EF (r = 0.95). The model showed that GCS contributes more than twice as much to EF than GLS. A significant reduction of GLS could be compensated by a small increase of GCS or wall thickness or reduced diameter. The model further demonstrated how EF can be maintained in ventricles with increased wall thickness or reduced diameter, despite reductions in both longitudinal and circumferential shortening. This was consistent with similar EF in 20 control subjects and 20 hypertrophic cardiomyopathy patients with increased wall thickness and reductions in both circumferential and longitudinal shortening (all p < 0.01). CONCLUSIONS: Reduced deformation despite preserved EF can be explained through geometric factors. Due to geometric confounders, strain better reflects systolic function in patients with preserved EF.

Comparison of Electrocardiography Markers and Speckle Tracking Echocardiography for Assessment of Left Ventricular Myocardial Scar Burden in Patients With Previous Myocardial Infarction.

Myocardial scar burden is an important prognostic factor after myocardial infarction. This cohort study compared assessment of left ventricle scar burden between pathological Q waves on electrocardiography (ECG), Selvester multiparametric ECG scoring system for scar burden, and global longitudinal strain (GLS) by speckle-tracking echocardiography 6 months after myocardial infarction. The scar burden was defined by late gadolinium enhancement cardiac magnetic resonance as fraction of total left ventricle tissue. ECG measures were presence of pathologic Q waves and Selvester scores. GLS was the average of peak strain from 16 left ventricle segments. In 34 patients aged 58 ± 10 years (mean ± SD), the scar burden was 19% (9, 26) (median [quartiles]) and 79% had scar burden >5%. Patients with scar burden >5% more frequently had pathologic Q waves (63% vs 14%) and had worse Selvester scores (5 [3, 7] vs 0 [0, 1]) and worse GLS (-16.6 ± 2.4% vs -19.9 ± 1.1%). Pathologic Q waves, Selvester scores, ejection fraction, and GLS related to scar burden in univariable analyses. Sensitivity and specificity for detecting scar burden >5% was 63% and 86% (pathologic Q waves), 89% and 86% (Selvester score), 81% and 86% (ejection fraction), 89% and 86% (GLS), and 96% and 71% (combination of Q waves, Selvester score, and GLS). In conclusion, Selvester score and GLS related to scars 6 months after myocardial infarction, and pathologic Q waves were only weakly associated with scar and GLS was associated with scar independently of ECG markers.