3. CVS Development And Congenital Heart Disease Flashcards
What happens to the endocardial tubes in embryo folding?
A pair fuse, to create one primitive heart tube within the cardiogenic field
Name the 6 areas of the primitive heart tube, from top to bottom
Aortic roots Truncus arteriosus Bulbus cordis Ventricle Atrium Sinus venosus
Why does cardiac looping occur?
The primitive heart tube elongates and runs out of room
What areas of the primitive heart tube does the left atrium form from?
Small portion of primitive atrium
Absorbs proximal parts of pulmonary veins
What areas of the primitive heart tube forms the right atrium?
Most of primitive atrium
Sinus venosus
Name the 3 shunts in the foetal circulatory system
Ductus venosus from liver to inferior vena cava
Foramen ovale from the right atrium to left atrium
Ductus arteriosus from the pulmonary trunk to the aorta
What does the 4th arch of the early atrial system form?
Right arch - proximal part of the right subclavian artery
Left arch - arch of the aorta
What does the 6th arch of the early arterial system form?
Right arch - right pulmonary artery
Left arch - left pulmonary artery and ductus arteriosus
Where does the eat recurrent laryngeal nerve become hooked around?
Ductus arteriosus
What is patent ductus arteriosus (PDA)?
Persistent communication between the descending aorta and pulmonary artery, leading to a shunt of blood from left to right (from aorta to pulmonary artery, as high pressure to low pressure) is acyanotic
What are the two causes of an atrial septal defect?
Septum primum - reabsorbed or too short
Septum secundum- too small
What is hypoplastic left heart syndrome?
Left heart is underdeveloped due to inadequate right to left flow in utero. Ascending aorta small. Need shunts for survival, persistent ductus arteriosus
What is thought to cause hypoplastic left heart syndrome?
Defect in development of mitral or aortic valves, leading to atresia and limited flow
Or ostmium secundum too small
How does the septum form in the developing heart?
Muscular portion of septum grows upwards towards the endocardial cushions, leaving a small gap (primary interventricular formamen). Membranous part of septum fills the gap
What causes ventricular septal defect?
Problem with membranous portion of interventricular septum.
What happens in septation of the outflow tract?
Endocardial cushions appear in the truncus arteriosus, grow towards each other and twist around each other, forming a spiral septum.
What does septation of the outflow tract form?
Aorta and pulmonary trunk
What occurs in transposition of the great arteries (aorta and pulmonary trunk swap ventricles)?
Cyanosis
Is related to development of aortic and pulmonary valves
Needs shunts to be viable - bi-directional shunting
What is tetralogy of fallot?
Ventricular septal defect
Over-riding aorta - right to left shunt, cyanosis
Pulmonary stenosis
Right ventricular hypertrophy
What is dangerous about patent ductus arteriosus?
Left to right shunt, so increased pulmonary artery and therefore pulmonary venous pressure
What is pulmonary atresia?
No opening in the right ventricle to the pulmonary trunk, requires right to left atrial shunt of venous return, and then blood to flow to lungs via persistent ductus arteriosus (left to right shunt).
What does an atrial septal defect eventually lead to?
Right heart failure
What is aortic coarctation?
Narrowing of the aorta, usually in area of ductus arteriosus which after birth becomes the ligamentum arteriosum
