Turbulent kinetic energy in normal and myopathic left ventricles

To assess turbulent kinetic energy (TKE) within the left ventricle (LV) of healthy subjects using novel 4D flow magnetic resonance imaging (MRI) methods and to compare TKE values to those from a limited group of patients with a spectrum of dilated cardiomyopathy (DCM).

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 timeframe. At peak early (E) and late (A) diastolic filling, the TKELV was compared to transmitral peak velocity, LV diameter, and mitral annular diameter.

In the majority of subjects, TKELV peaks were observed at E and A. Peak TKELV at E was not different between the groups (P = 0.33), and correlated with mitral annular dimensions (r(2) = 0.32, P = 0.01). Peak TKELV at A was higher in DCM patients compared to healthy subjects (3.0 ± 1.8 vs. 1.5 ± 0.8 mJ, P = 0.02), and correlated with LV diameter and transmitral velocity (r(2) = 0.36, P = 0.01 and r(2) = 0.47, P < 0.01, respectively).

In LVs of healthy subjects, 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.