Abstract Body (Do not enter title and authors here): Background:
Hemodynamic forces (HDF) reflect intraventricular pressure gradients and provide a dynamic, load-independent view of left ventricular (LV) function—beyond ejection fraction and strain. While both cardiac magnetic resonance (CMR) and transthoracic echocardiography (TTE) have been used to compute HDF, no study to date has directly compared these modalities in the same cohort.
Hypothesis:
Given that TTE underestimates LV volumes compared to CMR, we hypothesized that it would similarly underestimate HDF.
Methods:
Twenty healthy adults underwent 2D-TTE and cine-CMR within 7 days. LV volumetric, strain, and HDF parameters were extracted using dedicated software. HDF metrics included longitudinal (apex-to-base, A-B) and transverse (lateral-to-septal, L-S) components, the L-S/A-B ratio, and net impulse angle. Statistical analysis included paired comparisons and Bland–Altman plots (p < 0.05).
Results:
TTE significantly underestimated LV end-diastolic volume (87 [76–94] mL vs 121 [110–129] mL), ejection fraction (60% [56–64] vs 67% [64–70]), and global longitudinal strain (-21.3 +/- 3.9% vs -24.5 +/- 3.6%) (all p < 0.05). A-B and L-S HDF were also lower with TTE (A-B: 12.4 +/- 3.4% vs 26.1 +/- 6.6%; L-S: 2.6 +/- 1.2% vs 5.2 +/- 1.4%; both p < 0.001). The L-S/A-B ratio and impulse angle showed no significant differences. Across the cohort, TTE yielded consistently lower LV volumes, dV/dt, and HDF metrics. Bland–Altman analysis confirmed proportional bias in A-B HDF (mean difference: 13.64%, slope: 0.92, p = 0.005) and consistent bias in L-S HDF (mean difference: 2.66%, slope: 0.36, p = 0.325).
Conclusion:
TTE significantly underestimates LV HDF relative to CMR. As clinical and research use of HDF expands, consistency in imaging modality and the development of modality-specific reference values are essential to ensure accurate interpretation and application.