Turbulent Kinetic Energy in Normal and Myopathic Left Ventricles

Purpose: To assess turbulent kinetic energy (TKE) within the left ventricle (LV) of healthy subjects using novel 4D flow MRI methods and to compare TKE values to those from a spectrum of patients with dilated cardiomyopathy (DCM). Methods: 4D flow and morphological MRI-data were acquired in 11 healthy subjects and 9 patients with different degrees of diastolic dysfunction. TKELV was calculated within the LV at each diastolic time frame. At peak early (E) and late (A) diastolic filling, the TKELV was compared to transmitral peak velocity, LV diameter and mitral annular diameter. Results: In the majority of all subjects, peaks in TKELV could be observed at E and A. Peak TKELV at E was not different between the groups, and correlated with mitral annular dimensions. Peak TKELV at A was higher in DCM patients compared to healthy subjects, and was related to LV diameter and transmitral velocity. Conclusions: In normal LVs, TKE values are low. Values are highest during early diastole, and diminish with increasing LV size. In a heterogeneous group of DCM patients, late diastolic TKE values are higher than in healthy subjects. Kinetic energy loss due to elevated late diastolic TKE may reflect inefficient flow in dilated LVs.Contract grant sponsor: Swedish Heart-Lung Foundation; Contract grant sponsor: Swedish Research Council; Contract grant sponsor: European Research Council.