ABSTRACT
Objectives: Echocardiographic global myocardial work (GMW) indices recently emerged to non-invasively evaluate left ventricular (LV) myocardial performance with less load-dependence than LV ejection fraction (LVEF) or global longitudinal strain (GLS). Yet, few data exist on the descriptions of LV GMW indices in young people. We therefore aimed to provide normal reference values of LV GMW in a healthy young cohort, and simultaneously to investigate factors associated with non-invasive GMW indices. Materials and methods: A total of 155 healthy young people (age 10-24 years, 59% male) underwent transthoracic echocardiography were recruited and further stratified for age groups and divided by gender. Two-dimensional speckle-tracking echocardiography (2D-STE) were performed to determine LV GLS, peak strain dispersion (PSD) and GMW indices, which include global work index (GWI), global constructive work (GCW), global wasted work (GWW), and global work efficiency (GWE). LV peak systolic pressure was assumed to be equal to the systolic brachial artery cuff blood pressure. Results: Age and gender specific normal ranges for LV GMW indices were presented. On multivariable analysis, GWI and GCW correlated more closely with systolic blood pressure (SBP) than LV GLS, while both GWW and GWE independently correlated with PSD (P < 0.05 for all). There were no associations between any of the GMW indices with age, sex, body mass index, heart rate, left ventricular mass index as well as LV sizes or LVEF. Of noted, LV GMW indices had good intra-observer and inter-observer reproducibility. Conclusion: We reported echocardiographic reference ranges for non-invasive LV GMW indices in a large group of healthy young subjects, which are reproducible and reliable, and thus can be further used when assessing subclinical dysfunction in young people with myocardial diseases.
ABSTRACT
Objectives: Masked hypertension (MH) is not uncommon in the youth and may increase risks of long-term cardiovascular impairment. However, little is known about the subclinical heart damage in this group of patients. Currently, 3-layer speckle tracking imaging based on two-dimensional echocardiography is feasible to detect the early signs of myocardial damage. We therefore aimed to investigate whether subtle changes of cardiac function occurred in the young MH patients by using advanced quantification with layer-specific speckle tracking. Methods: A total of 40 adolescents with MH (age 18 ± 3 years, 73% males) and 40 age-, gender-, race-, and height-matched normotensive volunteers were enrolled in our study. MH was defined as one or more of the ambulatory blood pressure (BP) parameters (24-h, daytime and night-time average BPs) higher than ≥ 95th percentile for gender and height according to the local reference. Both comprehensive two-dimensional echocardiography with layer-specific strain analysis and 24-h ambulatory BP monitoring were performed. Longitudinal strain and circumferential strain in endocardial, mid-myocardial, and epicardial layers were determined accordingly with the dedicated software (EchoPAC software version 201, GE Healthcare, Horten, Norway). Results: Compared with normotensive controls, youths with MH had higher ambulatory pulse rate and left ventricular mass index, and were more obese. Interestingly, similar ventricular volumes and ejection fraction were observed in the study groups, but further analysis with layer-specific strains revealed that endocardial and mid-myocardial longitudinal and circumferential mechanical function were decreased in the young MH subjects when compared to normotensive individuals (all p < 0.05). However, there were no difference regarding radial strain and apical rotation derived from traditional speckle tracking analysis. Conclusion: Subclinical change of LV mechanic function assessed by layer-specific speckle tracking is present in youth with MH despite considered as normal with conventional ways.Thus, MH in youth should be monitored closely instead of labeling as an entirely benign entity.
