Objective To evaluate left ventricular systolic and diastolic functions of patients with coronary slow flow (CSF) according to left ventricular myocardial systolic/diastolic performances (MSP/MDP) by using two-dimensional speckle tracking echocardiography (STE).Methods Fifty patients with CSF diagnosed with coronary angiography (CSF group) and 45 patients without CSF (control group) underwent STE.Left ventricular systolic longitudinal,radial and circumferential peak strain and early-diastolic peak strain rate were measured,and left ventricular MSP and MDP were calculated,then the results were statistically analyzed between the 2 groups.Results Compared with control group,left ventricular systolic longitudinal,radial and circumferential peak strain and early-diastolic peak strain rate,MSP and MDP reduced in CSF group (all P＜0.05).The mean thrombolysis in myocardial infarction (TIMI) frame count (TFC) of coronary artery was negatively correlated with MDP (r=-0.23,P=0.04),and the number of affected coronary arteries was negatively correlated with MDP (r=-0.31,P=0.03).There was significant difference of MDP among patients with different numbers of affected coronary arteries and control group (all P＜0.05),and MDP in affected 2 and 3 coronary arteries patients were lower than those of the control group (all P＜ 0.05).Conclusion Left ventricular systolic and diastolic functions is impaired in patients with CSF.The mean TFC and the number of affected coronary arteries are negatively correlated with left ventricular diastolic function.Left ventricular MSP and MDP are comprehensive parameters in evaluating systolic and diastolic functions.