•Ventricular septal defect is the most common congenital heart defect. It is an abnormal opening between the right and left ventricles. It causes a holosystolic murmur (starts with S1 and ends with S2)
•Pressure from the left ventricle causes blood to flow through the defect to the right ventricle, resulting in increased pulmonary vascular resistance and right heart enlargement. Right ventricular and pulmonary arterial pressures increase, leading eventually to obstructive pulmonary vascular disease.
•Aortic stenosis is the narrowing of the aortic valve. This is a crescendo-decrescendo systolic murmur heard best at the second intercostal space, right sternal border.
•Patent ductus arteriosus results when the fetal ductus arteriosus fails to close completely after birth. There is often a machine-like murmur present.
•Coarctation of aorta is a defect that involves a localized narrowing of the aorta. There generally is no murmur assciated with this.