Braids in the heart: global measures of mixing for cardiovascular flows

The flow patterns in the heart, in health and disease, have been of great interest for several years. Modern fluid dynamics analyses elucidate how underlying inefficient energetic or mixing characteristics of these flow patterns correlate with adverse effects. Unfortunately, translation of such modern analyses to the clinical stage remains a challenge. In this experimental work, we propose and demonstrate that braids of random and sparse particle trajectories provide an intuitive, global and practical description of cardiovascular flows. Moreover, we expose the flow pattern in an experimental healthy left ventricle model as a highly effective blood mixer at the topological level. Flow topologies that deviate from this pattern are accompanied by a reduction in energetic efficiency, as shown through comparisons with diseased flow models. These results suggest an ideal clinical approach to patient follow-up and the evaluation of the performance of medical devices.

Automated summary

The flow patterns in the heart, especially in relation to health and disease, have attracted a lot of attention. Modern fluid dynamics analyses explain how inefficient flow patterns can lead to adverse effects. However, translating these analyses into the clinical setting remains difficult. In this experiment, the concept of using braids of random and sparse particle trajectories is proposed and demonstrated as an intuitive and practical description of cardiovascular flows. The study also reveals the highly effective blood mixing properties of a healthy flow pattern in a left ventricle model, which can be compared to diseased flow models to evaluate energetic efficiency.