The measurement of the size of the chambers of the heart relies on the cardiology department’s cardiac ultrasound program. Cardiac ultrasound procedures include the following: aortic root internal diameter, normal values are 20-37 mm; left atrial internal diameter, approximately 19-40 mm; left ventricular end-diastolic internal diameter, approximately 35-56 mm; left ventricular end-systolic internal diameter, approximately 23-35 mm; septal thickness, approximately 7-11 mm; and left ventricular posterior wall thickness, approximately 7-11 mm. Cardiac ultrasound not only depicts The heart ultrasound not only depicts the size of the chambers, but also analyzes the contractility of the heart. The contractility of the heart is mainly expressed by the EF value, also known as the ejection fraction. The normal value is about 50%-75% and the internal diameter of the pulmonary artery is about 18-24 mm.