Types of RVOT Obstructions

• Subvalvular (infundibular) 
• Annular
• Valvular
• Supravalvar
• Branch PA stenosis or hypoplasia
• Pulmonary atresia (missing valve with free PR or membrane)

RVOT Obstruction and PDA

• PDA may be kept open to maintain pulmonary circulation
• Surgery is usually performed at 4-6 months if there is cyanotic progression

Valvular (Valvar) PS

• Similar to AS by 2D echo
• Thickened and doming valve
• Doppler acceleration

Subvalvular (Infundibular)

• Thick muscle bundles beneath the pulmonic valve causing dynamic obstruction
• Double chambered RV
• Where moderator band is thickened or there are abnormal muscle bundles obstructing RV outflow
• Essentially splitting RV in half  

Subpulmonic Stenosis

• due to abnormal tricuspid tissue

Supravalvar

• Discrete or diffuse narrowing of MPA and/or branch PA’s