Ultrasound of the heart is a non-invasive test that uses ultrasound technology to examine the structure of the heart and large blood vessels, to probe for blood flow within the heart and large blood vessels, and to assess the function of the heart. There are two types of cardiac ultrasound: fetal cardiac ultrasound and adult cardiac ultrasound. Adults should have cardiac ultrasound in the following cases: 1. Patients who need to confirm or exclude cardiovascular diseases, patients with chest pain, dyspnea, palpitations, swelling of the lower extremities, murmurs on auscultation of the heart, or patients who have been diagnosed with cardiovascular diseases such as hypertension and arrhythmia, patients who need to assess the function of the heart, patients with other systemic diseases that may affect the heart, such as kidney disease, thyroid disease, etc., should also have cardiac ultrasound. Patients with these diseases should also have cardiac ultrasound examinations; 2. Patients who have been diagnosed with cardiovascular diseases need to be followed up, such as patients with valvular heart disease, hypertensive heart disease, congenital heart disease, heart failure, etc. also need to have cardiac ultrasound examinations; 3. Middle-aged and elderly people, usually over 40 years old, are recommended to have cardiac ultrasound examinations routinely when they have medical checkups; 4. Patients before and after use, etc., also need to do cardiac ultrasound examination. A comprehensive ultrasound examination of the fetus during pregnancy can lead to early detection of congenital heart disease and other heart conditions. Ultrasound for fetal heart examination is required in the following cases: pregnant women with diabetes mellitus, phenylketonuria, their own diseases and congenital heart disease, patients with structural and functional abnormalities of the heart found during fetal examination, patients with abnormal fetal heartbeat found during fetal heart monitoring, and patients with chromosomal abnormalities.