Objective To investigate the relationship between severity of coronary lesions and left ventricular diastolic function in patients with coronary heart disease(CHD).Methods Seventy-five consecutive patients with CHD confirmed by coronary angiography were divided into 4 groups according to extent of coronary lesions:mild stenosis,single vessel lesion,double vessel lesion and triple vessel lesion group.The systolic pressure and diastolic pressure in aorta,heart rate,left ventricular end-diastolic pressure (LVEDP),maximum and minimum value of the first derivative of left ventricular pressure (dp/dtmax,dp/dtmin),and the time constant of isovolumic pressure decay in early period of left ventricular relaxation(T) were determined by cardiac catheterization.The relationship between the severity of coronary stenosis and left ventricular diastolic function was analyzed.The left atrial dimension(LAD),left ventricular end-diastolic volume(EDV),left ventricular end-systolic volume(ESV),the early 1/3 filling volume (1/3V) and filling fraction (1/3 FF) of left ventricle were measured by left ventriculography and echocardiography.Left ventricular ejection fraction (LVEF) was also calculated.Peak systolic strain rate,peak early diastolic strain rate and peak late diastolic strain rate in each segment of left ventricles were measured with echocardiographic imaging.The correlation of the peak strain rates with the corresponding parameters derived with cardiac catheterization was analyzed.Results According to echocardiographic study,only the diameter of LAD was significantly larger in triple vessel lesion group 〔(38.74±4.57) mm〕 than in mild stenosis group 〔(33.87±3.80) mm〕 and single vessel lesion group 〔(33.77±3.94) mm〕.According to left ventriculography,the LVEDP,dp/dtmax,dp/dtmin,EDV and ESV were not significantly different between the groups.The T was significantly lower in mild stenosis group 〔(30.31±6.50) ms〕 than in single vessel lesion 〔(40.92±11.79) min〕,double vessel lesion 〔(43.02±15.83) ms〕 and triple-vessel lesion groups 〔(50.32±23.57) ms〕.The early filling 1/3V and 1/3FF was higher in mild stenosis group than in obvious stenosis groups.Conclusion The coronary lesion exerts certain effects on ventricular diastolic function in a coronary lesion severity dependent manner.Strain rate imaging in echocardiogram is accurate for evaluating diastolic dysfunction in patients with CHD.