Cardiac Embryology Chris Cunningham, M1 - PowerPoint Presentation

1. Cardiac EmbryologyChris Cunningham, M1

2. OutlineReview basic anatomy/physiology of the heartHeart OrganogenesisPrenatal CirculationNeonatal changesClinical application of concepts

3. Cardiovascular PhysiologyHumans, mammals and birds have a 2 circuit system: a pulmonary and systemic circuitHumans, mammals and birds have a 4 chambered heart; whereas amphibians have a 3 chambered heartVessels that transport blood away from the heart are arteriesVessels that transport blood towards the heart are veinsThe contractile cell in the heart is called a myocyte

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8. The heart is a pumpThe heart generates pressure gradients in which blood flows from high to low pressuresBlood flow is required for body tissue perfusionDelivery of O2, glucose and nutrients, removal of CO2 and wastes

9. OrganogenesisThe CV system arises from the mesodermAngioblasts initially replicate in clusters over the embryo and begin to form lumens, which fuse to create a primitive network of interconnected vessels

10. OrganogenesisFolding of the embryo brings angioblastic cords together to make a primitive heart tube, which starts contractingAB

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12. The Primitive Heart TubeSV -> A -> V -> BC -> TAThe Tube “Loops”

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14. OrganogenesisOnce the primitive heart tube loops, we need to establish 4 more divisions:Atrial SeparationVentricular SeparationAtrioventricular separation (Heart Valves)Aorticopulmonary SeptumThe central structure in these processes is the endocardial cushion

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16. Atrial SubdivisionALWAYS NEED A HOLE BETWEEN THE ATRIAMultiple steps: 2 sequential septa, 3 sequential openings = 5 structuresCommon for mistakes to occur -> congenital anomalies (Atrial Septal Defects)

17. Atrial SubdivisionStep 1: Septum Primum grows from the roof to the endocardial cushionStep 2: Foramen primum is a consequence of downward growthStep 3: Additional holes form in the septum primum which coalesce into the foramen secundumStep 4: Septum secundum begins to grow, leaving open the foramen ovale

18. Atrial Subdivision A

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21. Ventricular SubdivisionInterventricular Septum grows from the floor to the endocardial cushion. Muscular and membranous parts.Common for mistakes to occur -> congenital anomalies (Ventricular Septal Defect VSD)Interventricular septum

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23. Membranous (70%)Muscular (20%)

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25. Atrioventricular SeptationArise from the endocardial cushionsB

26. Aortiopulmonary SeptationThe Truncus Arteriosus subdivides into the aorta and pulmonary arteryA longitudinal septum forms and twists

27. Prenatal Circulation3 vessels Umbilical vein Umbilical arteries 3 shunts:- Ductus venosus- Oval foramen ● Most IVC blood passes through foramen → LA → LV → aorta → upper body ● Most SVC blood passes RA → RV → pulm.arteryDuctus arteriosus ● Most Pulm. artery blood passes → ductus (high resistance in pulm arteries) ● Blood from ductus → lower body.

28. Postnatal circulationAfter birth, the 6 structures needed only in-utero must close. They eventually become fibrotic.Their remnants have new names.Umbilical vein Ligamentum teresUmbilical arteries Medial umbilical ligaments3 shunts:Ductus venosus Ligamentum venosumOval foramen Oval fossaDuctus arteriosus Ligamentum arteriosum

29. Transposition of the Great VesselsWhat could cause this?What is needed for the infant to survive?

30. Tricuspid AtresiaWhat is required for viability?

31. Total Anomalous Pulmonary Venous Return (TAPVR)What is required for viability?

32. To Arms + Head

33. Extra Resourceshttps://www.youtube.com/watch?v=5DIUk9IXUaIhttps://www.youtube.com/watch?v=RpZHiwkFUM4