PA26.{4,9} | Congenital Heart Disease & Cardiomyopathies — Summary & Reflection

REFLECT

Pause and think through these integrating questions before moving to the summary:

1. A pregnant woman in her first trimester contracts rubella. Which specific congenital heart defects should the cardiologist screen for in her newborn — and what is the mechanism linking the virus to each defect?

1. A 25-year-old marathon runner collapses and dies during a race. Post-mortem shows asymmetric septal hypertrophy and myofibre disarray on microscopy. His younger brother is planning to run competitive sports. What would you tell the family about screening?

1. Compare and contrast the gross and microscopic appearance of dilated cardiomyopathy versus hypertrophic cardiomyopathy. How does the microscopy of each differ from normal myocardium?

1. Why is endomyocardial fibrosis clinically important in the Indian context — and how would you distinguish it from amyloid restrictive cardiomyopathy at the bedside and on pathology?

KEY TAKEAWAYS

Congenital Heart Disease — Key Framework:

• Left-to-right shunts (acyanotic initially): VSD (commonest CHD), ASD, PDA → volume overload → pulmonary HTN → Eisenmenger syndrome (shunt reversal, late cyanosis) → irreversible above Heath-Edwards Grade 4
• Right-to-left shunts (cyanotic from birth — the 5 Ts): Tetralogy of Fallot (commonest cyanotic CHD) — 4 components: VSD + overriding aorta + PS + RVH; boot-shaped heart; tet spells relieved by squatting (↑SVR)
• Obstructive: coarctation of aorta — preductal (neonatal failure) vs postductal (adult hypertension + rib notching); Turner syndrome association
• Aetiology: multifactorial (~90%); chromosomal (trisomies, 22q11.2); environmental (rubella → PDA/PS/ASD; maternal diabetes → TGA)

Cardiomyopathies — 3 Types:

Memory hook — ToF: 'PROVE it's ToF' — Pulmonary stenosis, RVH, Overriding aorta, VSD, Early cyanosis.