Applied Fluid-Structure Interaction Technique to Initial Insight into the Effect of Exercise on the Aortic Valve Stroke Work

The left ventricular stroke work is a measure of the work done by the left ventricle during the ejection of blood throughout per cardiac cycle. The aim of this investigation was to propose a model to numerically evaluate the stroke work for a healthy subject by using a fluid-structure interaction (FSI) simulation during exercise protocol. Aortic valve dimensions were calculated using an imaging technique of echocardiography. An FSI simulation was performed using an Arbitrary Lagrangian-Eulerian (ALE) mesh. Boundary conditions were defined by pressure loads on ventricular and aortic sides. Stroke work was predicted to increase to 121% from 60 bpm to 125 bpm, and it did not increase much above 125 bpm. Based on derived regression equations of our FSI results for stroke work and comparing of them with clinical ones, numerically-predicted stroke work values are in good agreements with published clinical data. The slope of stroke work changes to mean arterial pressure, while exercise protocol, is 168.08 ml which is 12.2% less than the average slope of clinical data. The y-axis intercept of stroke work changes to mean arterial pressure, while exercise protocol, is -11186 mmHg.ml which is 15% less than the average y-axis intercept of clinical data. Our results for the specific patient show that numerical methods can be proposed to predict good estimates of patient specific stroke work at different heart rates.