Background:

1. Stenosis of right ventricle outlet (infundibulum part) 右心室出口狹窄
   1. Less obstruction:L to R shunting
   2. More obstruction:R to L shunting→cyanosis(最常見的先天發紺原因,50-70%)
   3. May involved in chromosome 22, Degeorge symdrome
2. Right ventricle hypertrophy 右心室肥大
3. Ventricular septal defect 心室中膈缺損→R-to-L shunting(缺氧血打入左心室)
4. Aorta override septal defect(variable)
5. PD-dependant 要仰賴未關閉的動脈導管才能存活
   

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Etiology:

1. RVOT stenosis→RV pressure↑ →RV hypertrophy →VSD

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Clinical presentation:

1. Boot shape in x-ray(caused by R. ventricle hypertrophy) 靴狀心臟
2. Cyanosis in finger, lips 嘴唇手指發紺
3. Clubbing fingers 手指甲腫
4. Decreased PO2 血氧濃度下降
5. Failure to development and gain weight
6. Cyanosis spell 蹲下時缺氧的狀況緩解
   1. Increased vascular resistance
   2. Increased systemic pressure
   3. Pressure of left side > right side
   4. Transfer to L-to-R shunt

Treatment and prevention:

1. Prostaglandin therapy(PGE1)(i.v)→maintain ductal patency 給予PGE1維持動脈導管打開
2. Intracardiac repair(3-6 mo)
3. palliative shunt
4. Surgery

Reference:

1. Uptodate