[Effects of myocardial performance index on assessing left ventricular function in patients with primary...

To investigate the value of myocardial performance index (MPI) in assessing LV function in patients with primary hypertension (HP).

We studied 130 patients with HP (mean age 54.9±13.3 years)and 155 healthy control subjects (mean age 52.4±11.6 years). MPI was determined by tissue doppler imaging using the following formula: MPI=(isovolumic contraction time + isovolumic relaxation time)/ ejection time. The HP group was divided into hypertrophy subgroup( LVMI≥115 g/m(2) in males, or ≥95 g/m(2) in females) and normal mass subgroup(LVMI <115 g/m(2) in males, or<95 g/m(2) in females).

MPI was significantly different in control group, normal mass subgroup and hypertrophy subgroup(0.72±0.23 vs. 0.54± 0.17 vs. 0.45±0.11, P<0.001). Hypertrophy subgroup had significant higher MPI than normal mass subgroup(P =0.046), and both the groups had significant higher MPI than control group(all P<0.001). MPI was positively associated with age(r=0.369,P<0.001), Left ventricular end diastolic diameter(r=0.169, P<0.05), Sm(r=-0.211, P<0.001) and Em(r=-0.383, P<0.001) in control group. In multiple linear regression analysis, MPI was independently related to age (β=0.492, t=7.222,P<0.001) in control group. Among the HP patients, MPI was positively associated with left atrial area (r=0.293, P<0.001),intra ventricular septum(IVS) diameter (r=0.453, P<0.001), LVMI (r=0.453, P<0.001), relative wall thickness(r=0.458, P<0.001), and negatively associated with Sm(r=-0.414, P<0.001), Em(r=-0.508, P<0.001), left ventricular ejection fraction (r=-0.305, P<0.001) in bivariate analysis. In the multiple linear regression analysis, MPI was independently related to Em (β=0.401, t=4.256,P<0.001) and IVS diameter (β=-0.365, t=-3.878,P<0.001) in the HP patients.

The HP patients had elevated MPI, especially in the ones with LV hypertrophy. Tissue doppler imaging (TDI) derived MPI could be a useful index to evaluate the overall cardiac function in HP patients.