Left ventricular vortex formation in preterm infants assessed by blood speckle imaging

Abstract

Background A vortex is a rotational fluid structure formed by shearing of fluid layers. It forms during diastole in the left ventricle (LV) and helps redirect flow to the LV outflow tract for ejection, optimizing energy conservation. The aim of this study was to demonstrate the feasibility of detecting and analyzing LV vortices using a new ultrasound technique known as blood speckle imaging (BSI). Methods Conventional and BSI parameters were acquired in preterm infants referred for echocardiography. BSI feasibility and reliability were explored using highest frequency settings and optimized Nyquist limits. Vortex area was determined by tracing the outer vortex ring at maximum area. Peak vortex formation time (PVFT) was determined at time of maximum vortex area relative to the R‐wave, and vortex duration from frame‐by‐frame analysis of first appearance to vortex degradation. Results Left ventricle vortices were detected in 49 of the 50 preterm infants (weight 500–2020 g) with excellent intra‐ and inter‐observer reliability. Mean vortex area indexed to LV area was 0.19 (0.08). Peak vortex formation time was at 87 (7)% of the cardiac cycle, and vortex duration lasted 13 (4)% of the cardiac cycle. Vortex area correlated positively with LV length, end‐diastolic dimension, end‐diastolic volume, mitral annular (R +0.42, +0.50, +0.47, +0.50, all P < 0.01), and transmitral Vti (R +0.37, P < 0.01). PVFT correlated negatively with E, EA, and Ee’ (R −0.42, −0.47, −0.47, all P < 0.01). Conclusion Left ventricle vortex formation can be analyzed with two‐dimensional BSI and has the potential to complement existing parameters of cardiac health.

Left ventricular vortex analysis by high-frame rate blood speckle tracking echocardiography in healthy children and in congenital heart disease

“…Sphericity Index was defined as the ratio of vortex height/width. [1] When the main vortex was visible over several phases of the cardiac cycle, measurements were made for each phase and the phase where the vortex had the biggest dimension was selected for the final analysis. Vortex dimensions were indexed by body surface area (BSA) [11] and LV end-diastolic area (LVEDA) on apical 4 chamber view.…”

“…High-frame rate Blood speckle tracking (BST) echocardiography is a new technique for the assessment of blood flow. [1] , [2] , [3] , [4] , [5] , [6] , [7] BST may be used to visualize and quantify intra- and extra-cardiac flow patterns, and could improve our understanding of cardiac physiology. Compared to conventional Doppler, high-frame-rate BST is an ultrafast technique which generates up to thousands of frames per second and which is independent of the angle of insonation.…”

“…Compared to conventional Doppler, high-frame-rate BST is an ultrafast technique which generates up to thousands of frames per second and which is independent of the angle of insonation. [1] , [2] …”

“…Vortices naturally form in all cardiac chambers, but have been studied most extensively in the left ventricle (LV). [1] , [2] , [7] They represent a reservoir of kinetic energy in the LV, facilitating systolic ejection of blood flow into the left ventricular outflow tract (LVOT). It has been demonstrated in adults how the geometry and anatomical locations of vortices differ in health and disease.…”

“…Data on intracardiac vortices in healthy children are limited, [1] , [8] and studies on LV vortex formation in children with congenital heart disease (CHD) are lacking. BST has been technically validated in pediatric patients, but its clinical applications need to be further explored.…”