The cylinder model yielded significantly lower stroke volumes than modified Simpson's rule, indicating mitral annulus motion explains 82% of stroke volume and 18% is due to inward wall motion.
Cross-Sectional (n=20)
Does the cylinder model based on mitral annulus motion accurately calculate stroke volume compared to modified Simpson's rule in healthy adults?
Left ventricular pumping involves both atrioventricular plane displacement (accounting for 82% of stroke volume) and inward motion of the outer LV wall (accounting for 18%).
The outer contour of the heart has in some studies been shown to be constant during the heart cycle and the epicardial apex almost stationary whilst the base of the ventricles moves towards apex during systole. The base of the left ventricle has been regarded as a cylinder with constant cross-sectional area with changes in height during the heart cycle, the latter corresponding to the amplitude of mitral annulus motion (MAM). In this echocardiographic study, including 20 healthy adults, the stroke volume calculated by the cylinder model was significantly lower than by a reference method (modified Simpson's rule). MAM explained 82% of the stroke volume and 18% must, therefore, be explained by an inward motion of the outer left ventricular wall. A mean outer diameter shortening of about 3% (about 2 mm) was calculated.
Emilsson et al. (Tue,) conducted a cross-sectional in Healthy adults (n=20). Cylinder model for stroke volume calculation vs. Modified Simpson's rule was evaluated on Stroke volume. The cylinder model yielded significantly lower stroke volumes than modified Simpson's rule, indicating mitral annulus motion explains 82% of stroke volume and 18% is due to inward wall motion.
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