Left ventricular fluid kinetic energy time curves in heart failure from cardiovascular magnetic resonance 4D flow data

Abstract

BackgroundMeasurement of intracardiac kinetic energy (KE) provides new insights into cardiac hemodynamics and may improve assessment and understanding of heart failure. We therefore aimed to investigate left ventricular (LV) KE time curves in patients with heart failure and in controls.MethodsPatients with heart failure (n = 29, NYHA class I-IV) and controls (n = 12) underwent cardiovascular magnetic resonance (CMR) including 4D flow. The vortex-ring boundary was computed using Lagrangian coherent structures. The LV endocardium and vortex-ring were manually delineated and KE was calculated as ½mv2 of the blood within the whole LV and the vortex ring, respectively.ResultsThe systolic average KE was higher in patients compared to controls (2.2 ± 1.4 mJ vs 1.6 ± 0.6 mJ, p = 0.048), but lower when indexing to EDV (6.3 ± 2.2 μJ/ml vs 8.0 ± 2.1 μJ/ml, p = 0.025). No difference was seen in diastolic average KE (3.2 ± 2.3 mJ vs 2.0 ± 0.8 mJ, p = 0.13) even when indexing to EDV (9.0 ± 4.4 μJ/ml vs 10.2 ± 3.3 μJ/ml, p = 0.41). In patients, a smaller fraction of diastolic average KE was observed inside the vortex ring compared to controls (72 ± 6 % vs 54 ± 9 %, p < 0.0001). Three distinctive KE time curves were seen in patients which were markedly different from findings in controls, and with a moderate agreement between KE time curve patterns and degree of diastolic dysfunction (Cohen’s kappa = 0.49), but unrelated to NYHA classification (p = 0.12), or 6-minute walk test (p = 0.72).ConclusionPatients with heart failure exhibit higher systolic average KE compared to controls, suggesting altered intracardiac blood flow. The different KE time curves seen in patients may represent a conceptually new approach for heart failure classification.

Scan–rescan reproducibility of diastolic left ventricular kinetic energy, viscous energy loss and vorticity assessment using 4D flow MRI: analysis in healthy subjects

“…Multiple 4D flow MRI studies showed that patients with LV dysfunction present altered flow patterns through the LV with impaired preservation of inflow KE to the end of diastole and altered KE-time curves (the amount of KE inside the LV during each time step over the total cardiac cycle) [4,6,7,21], even in patients with normal to mild LV remodeling and normal to mildly depressed LV systolic function [7]. These KE changes in the LV could be a valuable diagnostic marker to evaluate diastolic function and might be useful for early detection of deteriorating ventricular function [1, 4-7, 21, 22], which could reduce patient morbidity and mortality [23].…”

“…In acquired heart disease, remodelling occurs which can lead to alterations in intracardiac hemodynamics [4]. Alteration in intraventricular KE derived from 4D flow MRI has been used to assess left ventricular (LV) and right ventricular (RV) (dys)function in patients with different stages of heart failure (HF) [4][5][6][7]. This is also the case in various congenital heart diseases.…”

“…4D flow MRI has recently emerged as a novel tool for in vivo quantification of intracardiac flow energetics, associated energy losses and vortical flow patterns by means of kinetic energy (KE) [4][5][6][7], viscous energy loss (EL) [1] and vorticity [8,9]. KE is the energy contained in the flow of the bloodstream due to motion and EL is the KE that is irreversibly lost due to viscosity-induced frictional forces within the blood flow [1].…”

Review of Journal of Cardiovascular Magnetic Resonance 2015

“…Patients with heart failure ( n  = 29, NYHA class I-IV) and controls ( n  = 12) underwent 4D flow CMR [165]. The authors used a quantitative approach to global LV performance as defined by the kinetic energy within the LV volume across the cardiac cycle and separated volume into regions defined by vortical or non-vortical flow across a range of left ventricular function.…”

Blood flow specific assessment of ventricular function: Visualization and quantification using 4D flow CMR

“…Quantification of blood flow using volumetrics and velocity information have led to formulation of advanced hemodynamic markers of cardiovascular function, such as kinetic energy (24,126,130,(138)(139)(140)(141)(142), turbulent kinetic energy (95,131,134,143,144), calculation of pressure gradients (145,146), wall shear stresses (147) and hemodynamic forces (148).…”