Occult heart disease is also known as asymptomatic myocardial ischemia. Patients who usually have no symptoms are diagnosed with coronary artery stenosis after coronary angiography or coronary CTA, or after electrocardiogram, which indicates ischemic changes, and then further coronary angiography or coronary CTA, which determines that the stenosis of coronary artery is more than 50%, are diagnosed with coronary heart disease. In other cases of occult heart disease, some children have congenital heart disease such as ventricular septal defect and atrial septal defect, but the children themselves do not have any symptoms such as cold, but through auscultation, cardiac ultrasound and other tests can confirm whether the children have heart disease.