289.1 🎓 醫孞生版

289.1.0.1 📌 䞀頁重點

289.1.0.1.1 Tetralogy of Fallot (TOF)
289.1.0.1.1.1 Anatomy — Four Components
  1. RVOT obstruction (infundibular pulmonic stenosis, may be valvular too)
  2. Ventricular septal defect (VSD) (perimembranous, large, malalignment)
  3. Overriding aorta (aorta straddles VSD)
  4. Right ventricular hypertrophy (RVH) — consequence
289.1.0.1.1.2 Epidemiology
  • ~ 10% of all CHD
  • Most common cyanotic CHD beyond infancy
  • 22q11 deletion (DiGeorge) common
  • ~ 90% reach adulthood now (vs 25% pre-surgical era)
289.1.0.1.1.3 Pathophysiology
  • RVOT obstruction → R→L shunt across VSD → desaturation
  • Cyanosis severity depends on degree of obstruction
  • “Tet spells” (hypercyanotic spells): infundibular spasm → severe ↓ pulmonary flow → severe cyanosis
  • Squatting (older children) ↑ SVR → reduces R→L shunt → relieves cyanosis
289.1.0.1.1.4 Diagnosis (Pediatric)
  • Cyanosis (variable)
  • “Boot-shaped heart” on CXR (RV hypertrophy + ↓ pulmonary vasculature)
  • ECG: RVH, RAD, RBBB
  • Echo: definitive
289.1.0.1.1.5 Surgical Repair
  • Intracardiac repair (Pott’s shunt, Blalock-Taussig palliative shunt historical → now full repair in infancy)
  • Closes VSD, relieves RVOT obstruction
  • Often results in pulmonic valve regurgitation (PR) as part of trade-off
289.1.0.1.1.6 Post-Repair Adult Issues

Pulmonic Regurgitation (PR) - Most common late complication - Progressive RV dilation, eventually RV dysfunction - Symptoms: exercise intolerance, arrhythmia, syncope

Right Ventricular Dysfunction - Chronic volume overload from PR - Predicts mortality, arrhythmia

Arrhythmias - Ventricular tachycardia from RVOT scar - Atrial flutter / fibrillation - AV block (less common) - Sudden cardiac death — leading cause of late mortality (~ 4%)

SCD Risk Factors (post-TOF) - QRS > 180 ms - Severe RV dilation - LV dysfunction (LVEF < 40%) - Inducible VT - Syncope - Older repair age

Other Issues - Residual VSD (uncommon) - RVOT obstruction recurrence - Aortic root dilation, AR (long-term)

289.1.0.1.1.7 Modern Treatment

Pulmonary Valve Replacement (PVR) - For severe PR with: - RV dilation (RVEDV index > 150 mL/m²) - RV dysfunction - Symptoms - Arrhythmia - QRS prolongation - Goal: prevent irreversible RV dilation - Options: - Surgical PVR (bioprosthetic) - Transcatheter PVR (TPVR): Melody, Harmony, SAPIEN - Less invasive - Bridge if anatomy permits

Ablation for VT - Targets scar near RVOT - ICD for primary prevention in high-risk

HF Therapy - Standard GDMT modified - Diuretics

289.1.0.1.2 Coarctation of Aorta
289.1.0.1.2.1 Anatomy
  • Narrowing of aorta, typically just distal to L subclavian artery
  • Two types:
    • Preductal (infantile): severe, often discovered in infancy
    • Postductal (adult): more common; less severe; in juxta-ductal location
289.1.0.1.2.2 Associations
  • Bicuspid aortic valve (50-80%) — very common
  • Turner syndrome (~ 30%)
  • VSD, PDA, MV abnormalities
  • Berry aneurysms (intracranial)
289.1.0.1.2.3 Pathophysiology
  • LV outflow obstruction → systemic HTN above coarctation
  • ↓ Perfusion below coarctation
  • Collateral circulation: intercostal arteries enlarge → “rib notching” on CXR
  • Untreated: HTN, premature CAD, aortic dissection, HF
289.1.0.1.2.4 Clinical Presentation
  • Adult: HTN in young patient (esp upper extremity HTN)
  • Differential BP: arms >> legs (> 20 mmHg)
  • Radial-femoral pulse delay
  • Headache
  • Leg fatigue with exercise
  • Cold feet
  • Epistaxis
  • Family history
289.1.0.1.2.5 Examination
  • HTN in arms, hypotension in legs
  • Radial-femoral delay
  • Reduced femoral pulses
  • Systolic murmur over L scapula (coarctation gradient)
  • Continuous murmur over chest/back (collaterals)
  • Click of bicuspid aortic valve
289.1.0.1.2.6 Investigations
  • CXR: “rib notching” (inferior aspect of ribs 4-8 from intercostal collaterals); “figure 3 sign” (pre + post-stenotic dilation)
  • ECG: LVH, LAE
  • Echo: gradient, anatomy
  • CMR / CTA: gold standard for anatomy
  • BP all 4 extremities
289.1.0.1.2.7 Treatment

Surgical Repair (Pediatric / Recurrent) - Resection + end-to-end anastomosis - Patch aortoplasty - Subclavian flap aortoplasty

Percutaneous (Adult First-Line) - Balloon angioplasty + stent placement - Especially native or recurrent coarctation - Long-term success > 90%

Pre-Op Considerations - Beta-blocker for HTN - Beware spinal cord ischemia (anterior spinal artery) - Hypertensive crisis post-op (paradoxical reactive)

289.1.0.1.2.8 Long-Term Issues
  • Persistent HTN (50% even after repair)
  • Re-coarctation
  • Aneurysm formation
  • Aortic dissection
  • Premature CAD
  • Bicuspid AV complications
  • Lifelong cardiology follow-up
289.1.0.1.3 Transposition of Great Arteries (TGA)
289.1.0.1.3.1 D-TGA (Complete TGA)
  • Aorta arises from RV, pulmonary artery from LV
  • Parallel circulations → fatal unless mixing (PFO, VSD, PDA)
  • Cyanosis at birth
  • “Egg on side” CXR
289.1.0.1.3.2 Modern Surgery
  • Arterial Switch Operation (Jatene) — in first 1-2 weeks
  • Anatomically corrected: aorta to LV, PA to RV
  • LV becomes systemic (normal physiology)
  • Long-term issues: coronary stenosis (re-implanted), neo-aortic valve dysfunction, PR
289.1.0.1.3.3 Historical Surgery (Older Adults)
  • Mustard / Senning (atrial switch)
  • Re-routes venous return at atrial level
  • Morphologic RV remains systemic ventricle
  • Long-term issues:
    • Systemic RV failure (eventual)
    • Tricuspid regurgitation (systemic AV valve)
    • Atrial arrhythmias (atrial flutter from scar)
    • AV block
    • Baffle obstruction / leak
289.1.0.1.3.4 Congenitally Corrected TGA (ccTGA / L-TGA)
  • AV discordance + ventriculoarterial discordance
  • “Doubly transposed” → physiologically corrected
  • Morphologic RV in systemic position
  • Eventual RV failure
  • Associated: VSD, PS, Ebstein-like TV (systemic AV valve)
  • Treatment: GDMT for systemic RV, valve surgery if severe TR
289.1.0.1.3.5 Common Issues in TGA Adults
  • HF (systemic RV failure)
  • Arrhythmia
  • Pacing requirements
  • Pregnancy risk (mWHO 3 typically)
289.1.0.1.4 Eisenmenger Syndrome
289.1.0.1.4.1 Definition
  • Any large L→R shunt → progressive PAH → eventual reversal to R→L
  • Cyanosis, polycythemia, hyperviscosity
  • Most often: large unrepaired VSD, AVSD, PDA, complex CHD
289.1.0.1.4.2 Pathophysiology
  • Chronic ↑ pulmonary blood flow → endothelial damage → vascular remodeling → PVR rises
  • Eventually PVR > SVR → reversed shunt
  • Cyanosis worsens with time
  • Polycythemia (EPO ↑) → hyperviscosity
  • Paradoxical embolism, cerebral abscess
289.1.0.1.4.3 Clinical
  • Adult cyanosis, clubbing
  • Exercise intolerance
  • Palpitations, syncope, hemoptysis
  • HF, arrhythmias
289.1.0.1.4.4 Hematologic
  • Erythrocytosis (Hct > 65%)
  • Iron deficiency despite ↑ Hct
  • Hyperviscosity symptoms: HA, vision change, dizziness
  • Bleeding diathesis (paradoxical — thrombocytopenia, vWF↓, platelet dysfunction)
289.1.0.1.4.5 Treatment

PAH-Specific Therapy (Class I) - Bosentan (BREATHE-5): improved 6MWT, hemodynamics - Macitentan (MAESTRO — modest) - Sildenafil / tadalafil - Inhaled treprostinil, iloprost - Selexipag - Sotatercept (STELLAR sub) — emerging

Supportive - Avoid pregnancy (maternal mortality 30-50%) — contraception critical - Iron supplementation if deficient - Avoid dehydration - IV filter for paradoxical embolism prevention - Hydration - Vaccinations: flu, pneumococcal, COVID-19 - No phlebotomy unless Hct > 65% AND hyperviscosity symptoms - Anticoagulation controversial (balance thrombosis vs bleeding) - Endocarditis prophylaxis (Class I for unrepaired cyanotic)

Surgical - Generally no shunt closure (irreversible PAH) - Heart-lung transplant for select severe cases

289.1.0.1.4.6 Prognosis
  • 10-year survival ~ 75-80% with modern therapy
  • Death: HF, sudden death, IE, thromboembolism

289.1.0.2 🩺 床邊速查

  • TOF 4 components: RVOT obstruction + VSD + overriding aorta + RVH
  • Post-TOF: PR most common; SCD risk if QRS > 180 ms, ↓ RV/LV function, syncope
  • TPVR (Melody/Harmony) for severe PR in adults
  • Coarctation: HTN in arms, radial-femoral delay, “rib notching”; balloon + stent
  • D-TGA: arterial switch (Jatene) — anatomically corrected
  • Mustard/Senning + ccTGA: systemic RV → eventual failure
  • Eisenmenger: PAH-specific therapy (bosentan BREATHE-5); avoid pregnancy