마더세이프 라운드 - Principles of Embryology (전이경 교수

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마더세이프 라운드 - Principles of Embryology (전이경 교수

  1. 1. 2010. 6. 15 Cardiac Development 관동의대 제일병원 병리과 전이경
  2. 2. Congenital Heart Disease Frequency of Congenital Cardiac Malformations Malformation Incidence/Million Live Births % Ventricular septal defect (VSD) 4482 42 Atrial septal defect (ASD) 1043 10 Pulmonary stenosis (PS) 836 8 Patent ductus arteriosus (PDA) 781 7 Tetralogy of Fallot (TOF) 577 5 Coarctation of aorta (CoA) 492 5 Atrioventricular septal defect (AVSD) 396 4 Aortic stenosis (AS) 388 4 Transposition of great arteries (TGA) 388 4 Truncus arteriosus 136 1 Total anomalous pulmonary venous connection (TAPVC) 120 1 Total 9757 J Am Coll Cardiol 39:1890,2002
  3. 3. Critical periods of development for various organ systems and the resultant malformations
  4. 4. First week of development: Second week of development: Ovulation to implantation Bilaminar germ disc Third week of development: Gastrulation (trilaminar germ disc)
  5. 5. Truncus Conus
  6. 6. Early Cardiac Morphogenesis I (Fertilization 3rd week) • Cardiogenic crest in splanchnic mesoderm in front of the neural plate • Bilateral endocardial tube from angioblastic day 18 cords • Cephalic and lateral folding of the embryo • Primary heart tube in the middle thorax day 22
  7. 7. A, day 18. B, day 20. C, day 21. D, day 22
  8. 8. Early Cardiac Morphogenesis II (Fertilization 4th week) • Segmentation : SV-AT-AVC- VT-BC • Layering : Endocardium – Myocardium- Epicardium Cardiac jelly • Looping
  9. 9. AV canal Atrium Sinus Bulbus Ventricle venosus cordis
  10. 10. Formation of Cardiac loop Normal D-looping A, day 22 B, day 23 C, day 24
  11. 11. Abnormalities of cardiac looping • Dextrocardia: • 심장이 오른쪽 흉곽에 위치하고 심첨이 오 른쪽을 향함 • Isolated form/ situs inversus
  12. 12. Formation of cardiac septa • Between 27th and 37th days of development (embryo: 5mm~ 16-17mm)
  13. 13. Atrial Septation (4-6 week) • Primary septum (septum primum) • Secondary septum (septum secundum) • Intermediate septum (septum intermedium)- endocardial cushion • Primary foramen (Foramen primum) • Secondary foramen (Foramen secundum) • Oval foramen (foramen oval)
  14. 14. Atrial Septal Defect • Type Secundum ASD (90%) Primum ASD (5%) Sinus venosus ASD (5%)
  15. 15. Secundum ASD (90%)
  16. 16. Endocardial cushion • Atrioventricular and conotruncal regions  Atrial and ventricular (membranous portion) septa  Atrioventricular canals and valves  Aortic and pulmonary channels • Abnormalities in ECC formation  ASD, VSD, AVSD  Defects involving great vessels (ex. TGA, TOF)
  17. 17. Ventricular Septation
  18. 18. 30 days Development of conotruncal ridges and closure of the interventricular foramen 35 days 7 weeks
  19. 19. Development of conotruncal ridges and closure of the interventricular foramen 6 weeks Beginning of 7 weeks End of 7 weeks
  20. 20. Ventricular Septation (5-8 week) • Muscular ventricular septum • Expansion of ventricles • Closure of interventricular foramen – Interventricular septum – Atrioventricular ECC – Outflow tract endocardial ridge
  21. 21. Ventricular Septal Defect • Type perimembranous (80-90%) muscular (5-20%) outlet or infundibular, (doubly committed) juxta-arterial (5-7%)
  22. 22. Perimembranous inlet extension type Muscular type (Doubly committed) juxta-arterial type Infundibular type Outlet type
  23. 23. Tetralogy of Fallot • Most common cyanotic CHD • Conotruncal region 이상  Unequal division of the conus resulting from anterior displacement of the conotruncal septum • Four features 1) Ventricular septal defect 2) Subpulmonary stenosis 3) Overriding of aorta 4) Right ventricular hypertrophy
  24. 24. • Essential defect : Anterosuperior displacement of outlet septum PA
  25. 25. Persistent truncus arteriosus • Conotruncal ridge – fail to fuse and to descend toward the ventricles – interventricular septum 형성에도 관여하므로 언제나 interventricular septal defect동반
  26. 26. Transposition of Great Arteries AO PT RV LV Conotruncal septum → fail to follow its normal spiral course and run straight down → Aorta from RV, PA from LV VSD, perimembranous type 동반하기도.
  27. 27. Neural crest cells • Crest cells – Vulnerable cell population – Deficient in superoxide dismutase and catalase enzymes that are responsible for scavenging free radicals.→ Easily killed by compounds such as alcohol and retinoic acid. • Essential for formation of much of the cranial region – Disruption of crest cell development ☞ Severe craniofacial malformations ☞ Examples: Treacher-Collins' Syndrome, DiGeorge anomaly, Robin sequence…. • Conotruncal endocardial cushions ☞ cardiac anomalies including persistent truncus arteriosus, TOF and TGA.
  28. 28. Velocardiofacial Syndrome/DiGeorge anomaly • 22q11.2 deletion • “CATCH 22” – Cardiac defects – Abnormal face – Thymic hypoplasia – Cleft palate – Hypocalcemia • Abnormal development of neural crest cells • Specific facial features – low-set ears, wide-set eyes, a small jaw, and a short groove in the upper lip • Etiology – Genetic causes, exposure to retinoic acids, alcohol, and maternal DM
  29. 29. Formation of Atrioventricular Valve • Endocardial cushion + Ventricular myocardium • Undermining of myocardium
  30. 30. Formation of Ventriculoarterial Valve 5 weeks 6 weeks 7 weeks 6 weeks 7 weeks 9 weeks
  31. 31. Development of Conduction System • Cardiomyogenic origin of conduction cells • Emergence of cardiac pacemaker in embryonic tube heart • Development of atrioventricular delay in looping, tube heart • Differentiation of fast conduction system during chamber septation
  32. 32. Left-right Sidedness and Heart • First organ with asymmetry • Genetic difference between right and left before morphologic asymmetry • LA and RA - left-right sidedness • LV and RV - anteroposterior axis
  33. 33. PITX2: a transcription factor responsible for establishing left sidedness
  34. 34. Subdivision of Primary Heart Tube Heart tube Looped heart Adult heart Bulbus cordis OFT truncus arteriosus Great arteries conus cordis RV Embryonic right ventricle Ventricle Embryonic left ventricle LV Atrioventricular canal (AVC) Atrium Atrium Atrium Sinus venosus Sinus venosus Caval veins
  35. 35. 4-mm embryo (end of the fourth week)
  36. 36. Venous system • Vitelline system -> portal system • Cardinal system -> caval system • Umbilical system -> disappear after birth
  37. 37. Double aortic arch
  38. 38. Abnormal origin of the right subclavian artery Interruption of aortic arch
  39. 39. Normal heart IVC

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