When a ventricular septal defect occurs, a loud, coarse murmur may be heard between the 3rd and 4th ribs of the left anterior chest wall during cardiac systole, requiring prompt surgical treatment. In normal people, the right and left ventricular chambers are not connected, but due to congenital developmental factors, a pathologic passage between the right and left ventricular chambers occurs, which is called a ventricular septal defect. When a ventricular septal defect occurs, the normal blood flow to the heart becomes abnormal, causing various murmurs on auscultation, especially during systole. During systole, the murmur between the 3rd and 4th ribs of the left anterior chest wall is characterized by loud, coarse sounds, some of which may be accompanied by tremors. In addition, there is a splitting and enhancement of the second heart sound. These characteristics need to be determined by the clinician. In the case of ventricular septal defects, surgery is required to seal the defect, and early intervention has a better prognosis. Ventricular septal defects require prompt treatment; cardiac auscultation should be performed by a specialist.