Determinants of myocardial work indices in women

By incorporating myocardial deformation and afterload, novel echocardiographic myocardial work indices appear to be advantageous compared to load-dependent left ventricular (LV) deformation analyses. As such, these indices may provide a more accurate and, above all, load-independent estimation of LV function in patients with chronically increased afterload. To date however, data on the relation of these indices to clinical and conventional echocardiographic parameters are scarce.

Our aim was to evaluate the relationship between myocardial work indices and age, body mass index (BMI), NTproBNP, the clinical history of arterial hypertension and diastolic dysfunction as well as selected conventional echocardiographic parameters in women.

We analyzed echocardiographic data of women included in the Berlin Female Risk Evaluation (BEFRI) trial. Global Work Index (GWI), Global Constructive Work (GCW), Global Wasted Work (GWW) and Global Work Efficiency (GWE) were calculated using commercially available software based on noninvasive pressure-strain loops. The impact of selected clinical and echocardiographic characteristics on myocardial work parameters was investigated by uni- and multivariate regression analyses.

A total of 224 women were included in the final analysis. 155 of them were normotensive and 69 had a history of arterial hypertension. Diastolic dysfunction was more prevalent in subjects with arterial hypertension. Study participants with arterial hypertension showed higher GWI and GCW whereas GWW and GWE did not significantly differ between groups. GCW and GWW were lower and GWE higher in the presence of normal diastolic function. In multivariate regression analyses, arterial hypertension, LV GLS, and interventricular septal thickness were significantly associated with GWI. GCW showed significant associations with the clinical history of arterial hypertension, LV GLS, age and IVRT. Similarly, LV GLS, IVRT and mitral inflow E wave deceleration time were identified to be significant determinants of GWW and GWE.

Our data confirm that, in a randomly selected sample of the general urban female population, myocardial work parameters are predominantly determined by LV GLS. In addition, the presence of arterial hypertension was identified to be a significant determinant of GWI and GCW, but not for GWW and GWE. Finally, a prolonged LV relaxation time was significantly associated with GWW and GWE, suggesting more wasted myocardial work and lower GWE values with increasing LV relaxation time.