Inclusion Criteria:  First admitted to hospital for chest pain and considered for diagnosis of coronary heart disease. Patients with relatively stable disease who can withstand elective coronary angiography. Cardiac ultrasound assessment before coronary angiography during hospitalization.  Exclusion Criteria:  No coronary angiography record. No cardiac ultrasound record. Cardiac ultrasonography is completed after coronary angiography. Severe heart valve disease. Severe congenital heart disease. Hyperdynamic heart disease such as hyperthyroidism and anemia. Pulmonary heart disease. Hypertrophic obstructive cardiomyopathy. According to the guidelines for coronary heart disease diagnosis, patients do not need coronary angiography. Malignant tumor. Acute coronary syndrome. Pericardial disease. Previously diagnosed as coronary heart disease or PCI. Mental or legal incapacity.