The most common congenital heart defects are:

• An abnormal opening in a wall that separates the parts of the heart (ventricular septal defect or atrial septal defect).
• Narrowing of a blood vessel or a heart valve in or near the heart (coarctation of the aorta, pulmonary valve stenosis, or aortic valve stenosis).
• Abnormal positioning of the major blood vessels that connect to the baby's heart (transposition of the great vessels, tetralogy of Fallot, total anomalous pulmonary venous return, or truncus arteriosus).
• Problems with the heart valves (mitral or tricuspid insufficiency).
• A blood vessel that remains open after birth (patent ductus arteriosus).
• Underdevelopment of the left side of the heart (hypoplastic left heart syndrome).