Tissue Doppler myocardial performance index rapidly quantified alterations in LV contractile state but was significantly affected by acute alterations in preload and afterload (P<0.05 vs baseline).
Does tissue Doppler myocardial performance index accurately quantify left ventricular contractile state and is it affected by acute alterations in loading conditions in an animal model?
Tissue Doppler myocardial performance index can rapidly quantify alterations in LV contractile state but is load-dependent, which must be considered when interpreting this metric.
p-value: p=<0.05
The Tei index is clinically useful to quantify left ventricular (LV) function, but it requires sequential Doppler recordings from two different views. A related myocardial performance index (MPI) using tissue Doppler (TD) can be rapidly calculated from a single beat; however, its ability to quantify contractility and the effects of acute changes in loading have not been determined. Our aim was to test the hypothesis that TD MPI can quantify contractile state but is affected by acute alterations in loading, using LV pressure-volume relations in an animal model. Eight dogs were studied by using mitral annular TD, high-fidelity pressure, and conductance catheters. TD MPI was calculated as (a' - b')/b', where a' was the duration of mitral annular velocity during diastole and b' was the duration of the systolic wave. End-systolic elastance (Ees), the time constant of isovolumic relaxation (tau), and peak positive and negative first derivative of pressure (dP/dtmax and dP/dtmin, respectively) were used as measures of LV function. Data were obtained at baseline, at dobutamine and esmolol infusion to alter contractile state, and at inferior vena cava and aortic occlusion to alter preload and afterload. TD MPI decreased from 0.83 (SD 0.19) to 0.62 (SD 0.20) with dobutamine and increased to 1.19 (SD 0.26) with esmolol. TD MPI significantly correlated with dP/dtmax (r = -0.76), Ees (r = -0.68), dP/dtmin (r = 0.82), and tau (r = 0.78); however, it was affected by acute decreases in preload from 0.83 (SD 0.19) to 1.09 (SD 0.36) and acute increases in afterload to 1.23 (SD 0.17). All the above increases and decreases and r values were significant (P < 0.05 vs. baseline). In conclusion, TD MPI can rapidly quantify alterations in LV contractile state but is affected by acute alterations in preload and afterload.
Cannesson et al. (Sat,) conducted a other in Left ventricular function (n=8). Alterations in contractile state and loading (dobutamine, esmolol, caval/aortic occlusion) vs. Baseline was evaluated on Tissue Doppler myocardial performance index (TD MPI) (p=<0.05). Tissue Doppler myocardial performance index rapidly quantified alterations in LV contractile state but was significantly affected by acute alterations in preload and afterload (P<0.05 vs baseline).