Abstract: Objective：To investigate the value of myocardial performance index （MPI) in assessing LV function in patients with primary hypertension (HP). Methods: 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/m² in males, or ≥95 g/m² in females) and normal mass subgroup（LVMI <115 g/m² in males, or<95 g/m² in females). Results: 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 independently 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. Conclusion: 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.

Key words: Hypertension, Hypertrophy, left ventriular, Echocardiography, Myocardial performance index