Congenital Heart Disease

Congenital Heart Disease - Heart's Blueprint

Structural heart abnormalities present from birth. Classified broadly by cyanosis and pulmonary blood flow (PBF).

Radiological Approach:

• CXR: Evaluates heart size, shape, pulmonary vascularity.
• Echocardiography: Primary diagnostic tool for anatomy and function.
• CT/MRI: For complex anatomy, extracardiac connections.

⭐ Tetralogy of Fallot classically presents with a "boot-shaped" heart (coeur en sabot) on CXR due to RV hypertrophy and an upturned apex. This is a common exam question!

Congenital Heart Disease - Pink & Puffy

• Acyanotic lesions with Left-to-Right (L-R) shunts.

• Presentation: "Pink" (no cyanosis initially), "Puffy" (signs of congestive heart failure due to ↑ pulmonary blood flow).

• Radiological Hallmark: Pulmonary plethora (engorged pulmonary vessels).

• Ventricular Septal Defect (VSD)

  • Most common CHD (excluding bicuspid aortic valve).
  • X-ray: Cardiomegaly (LV, LA, ±RV enlargement), ↑ pulmonary vascularity.
  • Holosystolic murmur.

• Atrial Septal Defect (ASD)

  • X-ray: RA, RV enlargement, prominent main pulmonary artery (MPA), ↑ pulmonary vascularity.
  • Wide, fixed splitting of S2.
  • Ostium secundum most common type.

• Patent Ductus Arteriosus (PDA)

  • X-ray: Cardiomegaly (LV, LA), prominent MPA, aortic knuckle, ↑ pulmonary vascularity.
  • Continuous "machinery" murmur.
  • Differential cyanosis if Eisenmenger develops (pink fingers, blue toes).

⭐ Eisenmenger Syndrome: Long-standing L-R shunts (VSD, ASD, PDA) can lead to pulmonary hypertension, shunt reversal (R-L), and cyanosis. Irreversible changes often preclude surgical correction of the primary defect once established. This is a critical complication to recognize early.

• Other causes: Atrioventricular Septal Defect (AVSD).

Congenital Heart Disease - Blue & Booted

• Cyanotic CHDs: Result from Right-to-Left (R→L) shunts.
  • 📌 Mnemonic: The 5 T's (Tetralogy of Fallot, Transposition of Great Arteries, Truncus Arteriosus, Total Anomalous Pulmonary Venous Return, Tricuspid Atresia).
• Tetralogy of Fallot (ToF): Most common cyanotic CHD >1 year of age. Classic "boot-shaped" heart.
  • 📌 Features (PROVe):
    • Pulmonary stenosis (Right Ventricular Outflow Tract Obstruction - RVOTO)
    • Right Ventricular Hypertrophy (RVH)
    • Overriding aorta
    • Ventricular Septal Defect (VSD)
  • X-ray: "Boot-shaped" heart (Coeur en sabot); ↓ pulmonary vascularity.
  • Clinical: "Tet spells" (hypercyanotic episodes); squatting ↑SVR (Systemic Vascular Resistance), ↓R-L shunt.
• Transposition of Great Arteries (TGA): Most common cyanotic CHD in newborns.
  • Pathophysiology: Parallel circulation (Aorta from RV, Pulmonary Artery from LV). Survival depends on mixing shunts (e.g., PDA, ASD, VSD).
  • X-ray: "Egg-on-string" sign; typically ↑PBF (pulmonary blood flow).
• Truncus Arteriosus: Single arterial trunk supplies all circulations; VSD always present. ↑PBF.
• TAPVR (Total Anomalous Pulmonary Venous Return): All pulmonary veins drain to RA or systemic veins (not LA).
  • X-ray: "Snowman" sign / "Figure-of-8" (supracardiac type); ↑PBF.
• Tricuspid Atresia: Absent tricuspid valve, hypoplastic RV. Requires ASD & VSD/PDA for survival. ↓PBF.

⭐ In Tetralogy of Fallot, the clinical severity and degree of cyanosis are primarily determined by the severity of pulmonary stenosis (RVOTO).

Congenital Heart Disease - Bottlenecks & Boxes

• Coarctation of Aorta (CoA)
  • Localized narrowing of aorta, typically juxtaductal.
  • Signs: Upper limb HTN, radio-femoral delay.
  • CXR: "3" sign (aortic knob, coarctation, post-stenotic dilatation), rib notching (inferior, 3rd-8th ribs).
  • CT/MRI Angio: Definitive.
• Ebstein's Anomaly
  • Apical displacement of septal & posterior tricuspid valve leaflets.
  • Atrialization of RV; small functional RV.
  • CXR: Globular or "box-shaped" heart, massive cardiomegaly (RA enlargement).
  • 📌 Associated with maternal lithium use.
• Hypoplastic Left Heart Syndrome (HLHS)
  • Underdevelopment of LV, aorta, aortic/mitral valves.
  • Ductal-dependent systemic circulation.
• Pulmonary Atresia with Intact Ventricular Septum (PA/IVS)
  • Complete RVOT obstruction, often hypoplastic RV.
  • Ductal-dependent pulmonary circulation.

⭐ In Coarctation of Aorta, the "figure 3" sign on CXR is formed by pre-stenotic dilatation of the aorta/left subclavian artery, the indentation of the coarctation, and post-stenotic dilatation of the descending aorta.

High‑Yield Points - ⚡ Biggest Takeaways

• Tetralogy of Fallot (TOF): Most common cyanotic CHD; CXR shows "boot-shaped" heart.
• Transposition of Great Arteries (TGA): CXR shows "egg-on-string" sign; severe neonatal cyanosis.
• Ventricular Septal Defect (VSD): Most common overall CHD; can lead to pulmonary hypertension.
• Atrial Septal Defect (ASD): Pulmonary plethora and right ventricular enlargement on CXR.
• Coarctation of Aorta: Rib notching (inferior, posterior ribs 3-8); "3" sign on barium/aortogram.
• Patent Ductus Arteriosus (PDA): Continuous "machinery" murmur; risk of Eisenmenger syndrome.
• Ebstein's anomaly: Apical displacement of tricuspid valve; "box-shaped" heart, atrialized RV.