• Ventricular septal defect (VSD)

• Overriding aorta

• Pulmonary valve stenosis

• Right ventricular hypertrophy

• Overriding aorta - aorta entrance is placed further to the right, a contracting right ventricle will send blood into the aorta - a greater proportion of deoxygenated blood enters the aorta.

• Pulmonary valve stenosis - Provides greater resistance to blood flow from RV encouraging blood flow thorugh VSD and into the aorta. determines extent of cyanosis

Overiding aorta and pulmonary valve stenosis = cyanosis

• Right ventricular hypertrophy = Caused by Increased strain on right ventricular wall as it attempts to pump against resistance

Risk factors

• Rubella infection
• Increased age of the mother (over 40 years)
• Alcohol consumption in pregnancy
• Diabetic mother

PC

Most cases picked up on antenatal scans

• An ejection systolic murmur caused by the pulmonary stenosis may be heard on the newborn baby check.
• Tet spells - sudden episodes of cyanosis during crying or feediing