Right ventricular outflow tract obstruction which may be infundibular, valvar or a combination of both. An overriding aorta that has deviated to the right. Right ventricular hypertrophy.
Some patients also have supravalve or branch pulmonary artery stenosis.
The pathophysiology is variable depending on the degree of right ventricular outflow obstruction. Rarely, adults are discovered who are unoperated. Some patients reach adulthood with only previous palliation. Central interposition tube graft shunt. Resection of infundibular muscle.