Comparison of left ventricular hemodynamic forces measured by transthoracic echocardiography and cardiac magnetic resonance imaging in healthy adults.

Hemodynamic forces (HDF), which reflect the forces exchanged between blood and cardiac tissues, can be derived from cardiac magnetic resonance (CMR) or transthoracic echocardiography (TTE). Although normal values are reported for each imaging technique, no study has compared HDF values within the same cohort so far. We aimed to compare left ventricular (LV) HDF parameters obtained from CMR and TTE in healthy subjects. Twenty volunteers underwent both cine-CMR and 2D-TTE (within 7 days) at the Heart Center University Medical Center in Astana, Kazakhstan. Images were analyzed offline using dedicated software to extract standard volumetric, functional, strain, and HDF parameters: longitudinal (A-B) and transverse (L-S) HDF, L-S/A-B HDF ratio, and HDF vector angle. Statistical comparisons were performed with significance set at p < 0.05; Bland-Altman plots assessed agreement. TTE significantly underestimated LV volumes, ejection fraction, and global longitudinal strain compared to CMR. Similarly, HDF values were lower with TTE for both longitudinal and transverse forces (A-B HDF: 12.4 ± 3.4 vs. 26.1 ± 6.6; L-S HDF: 2.6 ± 1.2 vs. 5.2 ± 1.4; both p < 0.001). Bland-Altman analysis confirmed systematic underestimation of HDF by TTE. These findings suggest that TTE and CMR cannot be used interchangeably for HDF assessment, particularly in serial studies.