Effects of Ageing on Aortic Circulation During Atrial Fibrillation; a Numerical Study on Different Aortic Morphologies

Figures

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  Figure 1. The statistical data of aortic morphology; (a) a schematic of an aorta with a normal SAT, (b) min and max values of the mean diameter at eleven different sections, (c) diameter increase rate per decade of life, (d) curvilinear length between different sections, (e) length increase per decade of life, (f) min and max values of the mean SAT diameters at the origin, with an increase range of 0.14–0.3 mm per decade of life.

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  Figure 2. Geometrical specifications of young, middle age and old groups; (a) curvilinear length between different sections, (b) diameter of the aortic conduit at different sections, (c) diameter of the coronaries and SAT at their origin, (d) constructed aortic geometries for different age groups; (e) flow rates at the inlet, Q(t).

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  Figure 3. Validation of the numerical code against the PC-MRI data of the 31-year-old healthy volunteer19; (a) the flow rates are depicted at three different cross sections (CSs) in a cardiac cycle (tcc). CS1 is before BCA, CS2 is between BCA and LCCA and CS3 is located at DDTA, (b) a qualitative comparison of streamlines at three time points at the AA, aortic arch, and PDTA.

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  Figure 4. Velocity vector and axial vorticity at three different points in a cardiac cycle (a)–(c), and seven cross sections for young, middle age, and old groups; iso-surface of vorticity, Q-criterion, 1200 s−1 (d)–(f), and LNH (d1)–(f1) at three timepoints in a cardiac cycle.

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  Figure 5. (a)–(i) Area weighted axial velocity (AV) and tangential velocity (TV) components over a cardiac cycle, (j)–(l) area-weighted, time-averaged AV and TV components. The results are shown at seven planes (Pi) in Fig. 4 for the young, middle age, and old groups during the normal, LVSD, and HFF conditions. For the LVSD cases, (d)–(f), the y-axis range is modified to clearly present the variations.

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  Figure 6. (a) Average flow rate through the coronary arteries, SAT, and DTA, (b) flow percentage through the coronary arteries, SAT, and DTA, and (c) mean pressure in mmHg at the level of aortic root.

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  Figure 7. TAWSS, OSI, and ECAP of different age groups for the normal, LVSD, and HFF.

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  Figure 8. Area-weighted TAWSS (Pa), OSI, ECAP (s−1), and time-averaged helicity metrics (H1, H2) (m s2) versus age and cardiac function for six discrete compartments, including (a) SAT, (b) AA, (c) AAA, (d) DAA, (e) PDTA, and (f) DDTA; (g) heatmaps of ECAP and H2. ECAP and H2 increase with respect to the baseline values of the young-normal condition are shown with YN subscript.