What are the symptoms of a ventricular septal defect? In normal individuals, there are no defects between the ventricular septa. However, if there is a small ventricular septal defect, such as less than five millimeters, typically ranging between two to three millimeters, this minor defect functions like small gaps between normal windows and doors, causing minimal shunting which generally does not significantly impact the patient, resulting in no obvious symptoms. However, if the defect is relatively large, such as exceeding five millimeters, causing significant left ventricular blood to shunt to the right ventricle, it can lead to congestion in the right ventricular system or pulmonary circulation. Under such conditions, patients may frequently experience respiratory infections, congestive heart failure, or in children, reluctance to eat, presenting feeding difficulties and developmental delays. Of course, if the defect continues to enlarge, achieving a size larger than the patient's aorta, the patient may show signs of significant right heart failure due to the damaged ventricular septum, necessitating emergency surgical intervention.