Objectives: To evaluate a new indicator of left ventricular global function: Myocardial velocity gradient (MVG) M-mode Doppler tissue imaging (DTI).
Background: MVG is a new indicator of regional left ventricular function and global left ventricular diastolic function. However, it is unclear whether MVG also is an indicator of left ventricular global function in comparison with invasive indices.
Methods: We performed conventional imaging and M-mode DTI in 85 subjects and calculated MVG at the posterior wall. We obtained satisfactory images in 65 subjects, who we divided into three groups: Noninvasive study group, invasive study group, and hemodialysis group. The noninvasive study group was divided into three subgroups (a younger normal subgroup, an older normal subgroup, and a cardiomyopathy subgroup), and MVG was compared with indices of conventional imaging. In the invasive study group, we compared MVG and indices of conventional imaging with hemodynamic data (peak positive and negative dp/dt, and the time constant T) using a high fidelity micromanometer-tipped catheter. In the hemodialysis group, we compared indices before hemodialysis with those after hemodialysis.
Results: Peak positive MVG correlated well with peak positive dp/dt (r = 0.79), and this did not change with hemodialysis (P = 0.87). Peak negative MVG also correlated well with peak positive dp/dt and the time constant T (r = 0.88 and r = 0.80), and this did not change with hemodialysis (P = 0.97).
Conclusions: Peak positive and negative MVG are sensitive and load-insensitive indicators of left ventricular function.