Introduction
Coronary heart disease (CHD) has been a hot spot in cardiovascular disease research. It is a heart disease caused by of the formation of coronary atherosclerotic plaque, which result in stenosis or obstruction of the vascular lumen, leading to myocardial ischemia, hypoxia and necrosis. According to the report published in 2016, CHD accounts for 20% of deaths in Europe, and is still one of the diseases with the highest morbidity and mortality in the world[1,2]. However, CHD involving three vessels disease (TVD) is a more extensive, diffuse and more serious disease than common CHD, and the left ventricular (LV) function can be impaired earlier. The main function of the LV is to transport blood to all parts of the body and undertake the blood supply to the whole body. So the effective evaluation of LV function in patients with TVD is very meaningful to the treatment and prognosis of patients. Traditional echocardiography has become the first choice for clinicians to diagnose heart disease, but it is less sensitive in early identification of cardiac function changes[3]. The 3D-STE is a quantitative tool to evaluate LV function with high accuracy and reliability[4]. Nesser et al.[5]found that 3D-STE in assessment of LV systolic function had a remarkable correlation with cardiac MRI. At present, 3D-STE has been widely applied to disease diagnosis and academic research in terms of cardiac[6-8]. This study used 3D-STE to quantitatively analyze the changes of systolic LV strain parameters and evaluate LV function in patients with TVD without myocardial infarction.