11. Embryology of the heart Flashcards
when is septation of the heart complete by
end of week 5 after fertilisation
Septation in the primitive atrium
septum primum grows midline from roof and cranial end
ostium primum forms + allows communication between developing L+R atria
Once the septum primum is complete ostium secundum forms
septum secundum grows from roof of RA
creates a valve allowing blood to cross from RA to LA
Septation in the primitive ventricle
single interventricular septum grows from roof of primitive ventricle
closes off foramen between ventricles
Congenital heart abnormalities causes
4% = single gene mutations
5% = teratogens
6% = chromosomal abnormalities
Ventricular Septal Defect %
25-50%
Atrial Septal Defect %
10%
Tetralogy of Fallot %
10%
Patent ductus arteriosus %
25%
Coarctation of the aorta %
10%
VSD
Ventricular Septal defect
mostly near the junction with the atria
breathe quickly
exhibit poor weight gain
slow at feeding
prone to chest infections
CYANOSIS
Atrial septal defect
associated with Trisomy 21
may not be detected till walking commences
may be closed by catheterisation
4 major consequences
of
Tetralogy of Fallot
1) ‘overriding aorta’
2) VSD
3) Stenosis between RV and PA
4) RV hypertrophy
- Most common cause of marked cyanosis at birth
- May be severe clubbing of the fingers
- May be fatal if untreated by operation
Tetralogy of Fallot
Patent Ductus Arteriosus
associated with hypoxia during birth
may result in pulmonary hypertension later in life
reversal of blood flow = lower body cyanosis
