If you suspect that your child has a precordial disease, you should go to the hospital for an examination. In general, the physician’s examination, meaning that the physician examines the patient with his or her hand or stethoscope, is a very important first step and should not be ignored. Hearing a heart murmur or finding the patient cyanotic are two of the most important signs to consider for heart disease. In most patients with these two signs, the doctor will perform a series of further tests to clarify the nature and severity of the heart disease. However, there are some severe heart diseases where there is neither cyanosis nor a large murmur, such as ventricular septal defect, and in some cases, even when they reach adulthood and some women have had children, they are not found to have heart disease after many doctors have examined them. In large ventricular septal defect with severe pulmonary hypertension, although no heart murmur can be heard, the patient’s medical history (such as the patient often suffered from pneumonia in the past, etc.) and the signs of enhanced second pulmonary artery sounds during auscultation should be combined with a high degree of caution that the patient has congenital heart disease. For patients suspected of having congenital heart disease, the diagnosis is usually made by electrocardiogram, cardiac X-ray and echocardiogram. In some difficult cases, cardiac catheterization is also required. Due to the current rapid development of imaging, many patients can be identified with CT or MRI with the examination of suspected congenital heart disease, and catheterization is now rarely done. In addition, for some patients who are highly suspected of having congenital heart disease, one should not arbitrarily conclude that the heart is normal by simply looking at it or doing an electrocardiogram, so that the time for surgery is lost. In such cases, it is best to get a careful examination by an experienced specialist and echocardiographer, or to review it after some time. Most congenital heart diseases can be identified after these tests. However, large vessel lesions outside the heart are not easily detected. If the venous system is abnormal or ectopically connected and the arteries are narrowed or constricted, the blood pressure of the extremities needs to be measured. A very simple and easy routine palpation of the femoral artery can suggest the diagnosis of aortic constriction, and a CT (CTA or CTV) with contrast injection or an MRI showing the vessels will clarify this type of disease very well.