Ventricular kinetic energy may provide a novel noninvasive way to assess ventricular performance in patients with repaired tetralogy of Fallot

Abstract

Objective Ventricular kinetic energy measurements may provide a novel imaging biomarker of declining ventricular efficiency in patients with repaired Tetralogy of Fallot (rTOF). Our purpose was to assess differences in ventricular kinetic energy (KE) with four-dimensional (4D) Flow MRI between patients with rTOF and healthy volunteers. Methods Cardiac MR (CMR), including 4D Flow MRI, was performed at rest in 10 subjects with rTOF and nine healthy volunteers using clinical 1.5T and 3T MRI scanners. Right and left ventricular kinetic energy (KERV and KELV), main pulmonary artery flow (QMPA), and aortic flow (QAO) were quantified using 4D Flow MRI data. Right and left ventricular size and function were measured using standard CMR techniques. Differences in peak systolic KERV and KELV in addition to the QMPA/KERV and QAO/KELV ratios between groups were assessed. KE indices were compared to conventional CMR parameters. Results Peak systolic KERV and KELV were higher in rTOF subjects (6.06±2.27mJ and 3.55±2.12mJ, respectively) than healthy volunteers (5.47±2.52mJ and 2.48±0.75mJ, respectively) but not statistically significant (p= .65 and p= .47, respectively). The QMPA/KERV and QAO/KELV ratios were lower in rTOF subjects (7.53±5.37mL/(cycle-mJ) and 9.65±6.61mL/(cycle-mJ), respectively) than healthy volunteers (19.33±18.52mL/(cycle-mJ) and 35.98±7.66mL/(cycle-mJ), respectively; p< .05). QMPA/KERV and QAO/KELV were weakly correlated to ventricular size and function. Conclusions Greater ventricular KE is necessary to generate flow in the pulmonary and aortic circulations in rTOF. Quantification of ventricular KE in patients with rTOF is a new observation. Future studies are needed to determine if changes in ventricular KE can provide earlier evidence of ventricular dysfunction and guide future medical and surgical interventions.

Vector flow mapping analysis of left ventricular energetic performance in healthy adult volunteers

“…However, assessing EL allows the estimation of the cardiac workload with ease as a single parameter. Like EL, KE plays an important role in assessing left ventricular function [33, 34]. In the present study, we focused particularly on the KE in the LVOT, which enabled us to assess left ventricular systolic function similar to cardiac output.…”

Assessment of intracardiac flow and vorticity in the right heart of patients after repair of tetralogy of Fallot by flow-sensitive 4D MRI

“…In the cases presented here, the clockwise RA vortex and the umbrella-like pattern around the tricuspid valve were found in volunteers. The appearance of vortices seems to be necessary for optimized flow kinetics and efficiency as previously discussed 22, 35, 46 . Thus, the sole observation of vorticity does not indicate compromised ventricular function; however, an approach using vorticity analysis may allow for the computation of physiologically normal ranges.…”

“…In this study the standard of care was using a static orthogonal plane to the MPA for evaluating pulmonary valve flow. A recent publication applied the quantification of ventricular kinetic energy (KE) extracted from 4D flow MRI data to assess ventricular performance in rTOF patients 22 . Ventricular KE was higher in patients than in volunteers suggesting that this could represent a potential biomarker of ventricular impairment.…”

“…Additionally, one should take into account the exact localization and appearance of vortices during the heart cycle to determine the quality of “physiological” and “pathological” vortices. In this context, the aspect of RV-PA coupling which was discussed by Jeong et al 22 is of great interest because turbulent ventricular flow could lead to changes in KE which results in ventricular-vascular inefficiency in rTOF patients.…”

Turbulent kinetic energy in the right ventricle: Potential MR marker for risk stratification of adults with repaired Tetralogy of Fallot

“…No statistically significant difference in TKE levels were seen between the healthy controls and the lower PR fraction group; however, the higher PR fraction group presented overall higher levels of TKE than the other two groups. A recent study by Jeong et al showed that the RV kinetic energy (KE) corrected for body surface area was slightly higher in a cohort of rToF patients with PR compared to healthy volunteers, whereas no significant intergroup difference in pulmonary flow (RV stroke volume) was observed, reflecting a higher energy loss in the RVs of patients with rToF without the ability to generate increased flow . Further, Jeong et al found that the highest KE was seen in the RVOT during both systole and diastole, due to the presence of PR.…”