4305The interrelation of left ventricular geometry with myocardial work

Abstract

Abstract Introduction A novel echocardiographic method to non-invasively determine myocardial work based on speckle-tracking derived longitudinal strain and blood pressure has recently been validated and offers new opportunities to study mechanistic associations. Left ventricular (LV) dilation and LV hypertrophy are acknowledged precursors of myocardial dysfunction and ultimately heart failure, but the mechanisms are still not well understood. We aimed to assess the association of LV geometry and myocardial work in a non-diseased population. Methods The Characteristics and Course of Heart Failure STAges A/B and Determinants of Progression (STAAB) cohort study carefully characterized a representative sample of the population of a medium-sized town in Germany, aged 30–79 years. By off-line analysis of the standardized, quality-controlled transthoracic echocardiograms the following parameters describing myocardial work can be derived. Global constructive work (GCW): work performed during shortening in systole and adding negative work during lengthening in isovolumic relaxation; global wasted work (GWW): negative work performed during lengthening in systole adding work performed during shortening in isovolumic relaxation; global work efficiency (GWE): GCW/(GCW+GWW). Further, LV volumes and mass were measured and indexed to body surface area. Results Myocardial work analysis was performed in 1568 individuals, who were in sinus rhythm, had preserved LV ejection fraction (EF), and were free from significant valvular disease (50.3% female, aged 53±12 years). In linear regression, we included age, sex, LVEF, low-density lipoprotein (LDL), glycosylated hemoglobin (HbA1c), heart rate, body mass index, hypertension as well as LV mass index (LVMi) and LV end-diastolic volume index (LVEDVi) as parameters of LV geometry. We found increasing LVEDVi (52±10 mL/m2), associated with higher GWW (+0.35, p<0.001) and lower GWE (–0.01, p<0.05), while increasing LVMi (73±17 g/m2) was associated with both, higher GWW (+0.23, p<0.01) and GCW (+1.6, p<0.05) resulting in a lower GWE (–0.09, p<0.01). Conclusion The new echocardiography-based method to non-invasively assess myocardial work offers new insights into the relationship of LV geometry and myocardial work in a non-diseased population. While larger LV volumes were associated with more wasted work, higher LV mass was associated with an increase in both constructive and wasted work. Both alterations of LV geometry adversely affected myocardial work efficiency. This new echocardiographic method is change-sensitive and thus holds promise to further explore the relationship of LV geometry with myocardial work in different disease entities. Acknowledgement/Funding Funding of the STAAB cohort study in the frame of the Comprehensive Heart Failure Center, BMBF 01EO1004 and 01EO1504