Comparative numerical study on left ventricular fluid dynamics after dilated cardiomyopathy

Introduction: The role of flow on the progression of left ventricular (LV) remodeling has been presumed, although measurements are still limited and the intraventricular flow pattern in remodeling hearts has not been systematically evaluated in a clinical setting. Comparative evaluation of intraventricular fluid dynamics is performed here between healthy subjects and dilated cardiomyopathy (DCM) patients. Methods: LV fluid dynamics is evaluated in 20 healthy young men and in 8 DCM patients by combination of 3D echocardiography with direct numerical simulations of the equation governing blood motion. Results are analyzed in terms of quantitative global indicators of flow energetics and blood transit properties that are representative of the qualitative fluid dynamics behaviors. Results: The flow in DCM exhibited qualitative differences due to the weakness of the formed vortices in the large LV chamber. DCM and healthy subjects show significant volumetric differences; these also reflect in flow properties like the vortex formation time, energy dissipation, and sub-volumes describing flow transit. Proper normalization permitted to define purely fluid dynamics indicators that are not influenced by volumetric measures. Conclusion: Cardiac fluid mechanics can be evaluated by a combination of imaging and numerical simulation. This pilot study on pathological changes in LV blood motion identified intraventricular flow indicators based on pure fluid mechanics that could potentially be integrated with existing indicators of cardiac mechanics in the evaluation of disease progression.