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Left Ventricular Dynamics

This effect of using a mechanical support device – rotary blood pump or balloon pump – on the left ventricle is profound.  The dynamics of contraction and filling of the left ventricle are markedly altered such that:

  • the aortic valve might fail to open
  • an apical cannula can interfere with or damage the intraventricular septum
  • the ventricle might suck-down around a cannula and occlude flow in to the cannula
  • blood might clot over the entrance to the apical canula and occlude blood flow in to it
  • partial prolapse or leakage of the aortic valve occurs.

This research investigates ventricular dynamics on the bench.  A mock loop incorporating a a pneumatically controlled left ventricle is used to emulate the hydrodynamics of the systemic circulation.  Cardiac contractility and mechanical support ratios are varied in order to map allowable operating space for the support device.  Particle Image Velocimetry (PIV) and Computational Fluid Dynamics (CFD) are used to investigate flow patterns within the ventricle to reduce the likelihood of clotting.  We are currently investigating the use of more realistic ventricle shapes derived from CT scans of healthy and heart-failure patients and more realistic contraction mechanics and pneumatic control.

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