Left ventricular myocardial work indices in pediatric hypertension: correlations with conventional echocardiographic assessment and subphenotyping

Myocardial work (MW) is a novel parameter that incorporates non-invasive estimates of left ventricular (LV) systolic pressure into the interpretation of strain, thus overcoming the limitations of load dependency traditionally encountered with LV fractional shortening (LVFS), ejection fraction (LVEF), and global longitudinal strain (GLS). However, data on MW in the pediatric population with hypertension are lacking. Conventional markers of LV function and MW indices were obtained from 88 echocardiographic examinations in 76 children with hypertension (47 males, 15.5 ± 2.96 years). When compared with a previously published cohort of 52 healthy controls, global work index (GWI) and global constructive work (GCW) were both significantly elevated while LVEF and GLS were not impaired but rather mildly increased. On multivariable analysis, GWI was correlated with systolic blood pressure (slope = + 16, p < 0.001) and GLS (slope = -100, p < 0.001), while GCW was correlated with systolic blood pressure (slope = + 18, p < 0.001), GLS (slope = -101, p < 0.001), male sex (slope = -75, p = 0.016), and LV mass (slope = -0.93, p < 0.001). Global wasted work (GWW) was correlated with age at echo visit (slope = -4.5, p = 0.005) and GLS (slope = + 5.5, p < 0.001). The opposite occurred for global work efficiency (GWE; slope = + 0.20, p = 0.011, and slope = -0.48, p < 0.001, respectively). Principal component analysis and k-means clustering revealed 4 subphenotypes which differed in terms of etiology, afterload, and compensation stage of the disease. Conclusion: Non-invasive MW shows a good correlation with conventional markers of LV function and may help refine the assessment of hypertensive heart disease in children. What is Known: • Myocardial work (MW) is a novel parameter that incorporates non-invasive estimates of left ventricular (LV) systolic pressure into the interpretation of strain, thereby accounting for both deformation and afterload. • Although the usefulness of MW in the assessment of myocardial function beyond conventional markers has been demonstrated in various clinical populations, data in the pediatric population with hypertension are currently lacking. What is New: • Compared to normal values in healthy children, global work index and global constructive work were increased in those with hypertension, while LV ejection fraction and global longitudinal strain were not impaired. • Machine learning identified 4 subphenotypes which differed in terms of etiology, afterload, and compensation stage of the disease.