Optimal vortex formation as an index of cardiac health

Abstract

Heart disease remains a leading cause of death worldwide. Previous research has indicated that the dynamics of the cardiac left ventricle (LV) during diastolic filling may play a critical role in dictating overall cardiac health. Hence, numerous studies have aimed to predict and evaluate global cardiac health based on quantitative parameters describing LV function. However, the inherent complexity of LV diastole, in its electrical, muscular, and hemodynamic processes, has prevented the development of tools to accurately predict and diagnose heart failure at early stages, when corrective measures are most effective. In this work, it is demonstrated that major aspects of cardiac function are reflected uniquely and sensitively in the optimization of vortex formation in the blood flow during early diastole, as measured by a dimensionless numerical index. This index of optimal vortex formation correlates well with existing measures of cardiac health such as the LV ejection fraction. However, unlike existing measures, this previously undescribed index does not require patient-specific information to determine numerical index values corresponding to normal function. A study of normal and pathological cardiac health in human subjects demonstrates the ability of this global index to distinguish disease states by a straightforward analysis of noninvasive LV measurements.cardiac dysfunction ͉ left ventricle ͉ mitral flow ͉ biofluid dynamics P revious research has indicated that dynamics of the cardiac left ventricle (LV) during diastolic filling play a critical role in dictating overall cardiac health (1-8). The flow of blood from the atrium to the ventricle of the left heart during early diastolic filling, known as the E wave, has been observed in both in vivo and in vitro studies to cause the formation of a rotating fluid mass called a vortex ring (9-11, Fig. 1 a and b). This process of vortex ring formation has been studied extensively in in vitro experiments (12-15), where it has been demonstrated that fluid transport by vortex ring formation is more efficient than by a steady, straight jet of fluid (16). Furthermore, it was recently discovered that energetic constraints limit the maximum growth of individual vortex rings (14).These results suggest the possibility that vortex ring formation may be optimized in naturally occurring fluid transport processes, especially in biological systems that depend on efficient fluid transport for their survival. In ref. 17, in vivo and in vitro data were used to support the notion that, in principle, the vortex formation process can dictate optimal kinematics of any biological fluid transport system, including the human heart.In this work, we test the hypothesis that the process of vortex ring formation during early LV diastole affects cardiac health and also serves as an indicator of cardiac health. To quantify the process of vortex ring formation and its potential optimization, a quantitative index is required. The index is most useful if it is dimensionless, so that it can be com...

Asymptotic Model of Fluid–Tissue Interaction for Mitral Valve Dynamics

“…(10) due to a major horizontal deviation of the flow. In any case, the results are in complete agreement with those reported in the literature for healthy subjects, 12 showing little higher values in correspondence of intermediate values of e in the range 0.1-0.2. The VFT computed on the basis of the diastolic flow rate and the fixed geometry of the mitral annulus are also reported for reference, showing how the valvular motion must be taken into account in properly estimating the VFT.…”

“…9,10,16 It is believed that such vortices play a central role in the overall synchronicity of the beating heart, 25 and the quantification of the vorticity patterns has driven attempts to improve understanding of cardiac diseases. 12,14 The natural and apparently harmonious behavior of the flowing blood modifies in presence of a dysfunctional mitral valve (MV) or by the insertion of prosthetic ones. 21,28 In fact, the vortex formation process is intrinsically connected to the dynamics of the mitral leaflets while they interact with the blood crossing the valve during diastole.…”

Three‐dimensional quantification of vorticity and helicity from 3D cine PC‐MRI using finite‐element interpolations

“…Qualitative or semi-quantitative approaches have been proposed to evaluate the vorticity and helicity from 3D cine PC-MRI in the context of heart failure and ventricular dysfunction (20)(21)(22)(23)(24)(25). Other semi-quantitative methods have been developed to assess vortices in the aorta and pulmonary artery, including features such as the vortex size, duration of the vortex, and other scores related to the degree of the rotation of the vortices (8,12,(26)(27)(28)(29)(30)(31).…”

On the accuracy of intracardiac flow velocimetry methods

“…Alternatively, formation of unnatural vortices can be a sign of adverse blood flow, which may indicate progressive LV dysfunction [18][19][20][21]. The knowledge gained about LV fluid dynamics, and in particular the associated vortical flow motion, has introduced novel clinical indicators for LV function based on vortex dynamics [18,19,[21][22][23][24][25].…”