Congenital Heart Defects (cyanotic)

Tetralogy of Fallot


  • MC cyanotic CHD

  1. Stenotic pulmonary artery ➔ right ventricle outflow obstruction

  2. Stenosis ➔ RVHboot shaped CXR

  3. VSD (stenotic pulmonary artery ➔ ↑ RV pressure ➔ R ➔ L shunt ➔ cyanosis)

  4. Aorta overrides septal defect (can be really close to defect)

    • Degree of stenosis ➔ severity of cyanosis


  • Mild obstruction ➔ mild cyanosis; severe obstruction ➔ severe cyanosis

  • Tet spell: hypercyanosis with stressor (feeding, pooping, crying, activity)

    • Squatting ➔ ↑ afterload ➔ temporary shunt reversal ➔ sx relief

  • Harsh systolic murmur of VSD


  • ECHO (fetal echo ➔ dx before birth)

  • CXR shows boot shaped heart (RVH moves LV over)


  • Newborn gets prostaglandin to maintain PDA til surgery (can cause apnea, secure airway first)

  • If missed prenatally and presents with severe RV outflow obstruction (activity/stressor ➔ tet spell)

    • O2 (duh?), knees to chest, sedate (morphine), ± β-blockers

  • HF sx get ionotropes and loops (ACEi contraindicated)

Transposition of the great vessels


  • Dextro: Reversal of aorta and pulmonary artery

    • RV ➔ aorta ➔ body ➔ RA (circuit of deoxy blood)

    • LV ➔ pulmonary artery ➔ lungs ➔ LA (circuit of oxygenated blood)

    • Survival depends on connection between circuits via VSD, PDA, ASD

  • Levo: Vessels in appropriate place but ventricles swapped

    • No obvious sx at birth but the tricuspid valve isn't designed for high pressure ➔ ↑ risk of HF


  • Dextro: Low O2 sat despite supplemental O2


  • ECHO

  • CXR shows egg on string - (enlarged heart ➔ egg, atrophy of thymus ➔ string)


  • Maintain mixing of two circuits: Prostaglandin infusion to maintain PDA, ± balloon septostomy to enlarge or create ASD until

    • until arterial switch operation