Vector mapping of blood flow in the left ventricle in healthy and patients with aortic stenosis

Objective. The aim of the study was to apply a new echocardiographic technology in the visualization of turbulent blood flow and energy expenditure in healthy and patients with aortic stenosis. Materials and methods. Intraventricular blood flow studies were performed in 10 healthy subjects (average age 37±8 years) and 10 patients with aortic stenosis (average age 67±9 years) using the LISENDO 880LE premium ultrasound system (Fujifilm Corporation, Japan). Intracardiac blood flows were studied using a specialized software module Vector Flow Mapping (VFM). The structure of blood flow inside the left ventricle was assessed by the location of turbulence zones with the determination of the area, direction and acceleration of the vortex in certain phases of the cardiac cycle: isovolumic contraction, systole, diastole and atrial contraction. The results were calculated based on the average acceleration of blood flow and the area of turbulent flow in the outflow tract of the left ventricle. Results. Pressure gradients on the aortic valve and its opening area were evaluated to characterize aortic stenosis. The vortices formed during the filling of the left ventricle have a certain geometry and anatomical location that determine the directional blood flow during the shock discharge. The mechanics of myocardial contraction were assessed by three components: blood flows in the heart cavities, energy distribution and expenditure during the cardiac cycle, and their relationship between the area of turbulent flow and acceleration. Conclusion. Turbulence plays an important role in the normal functioning of the heart, supporting the movement and direction of blood flow. The energy dissipation during the cardiac cycle in aortic stenosis is determined by the area of the aortic valve opening, the zones of additional turbulence in the left ventricle, and the acceleration of turbulent vortices.