Cardiovascular system III Flashcards
(26 cards)
What is the largest category of human birth defects, accounting for 1% of live births?
Congenital Heart Defect (CHD), affects blood flow of the heart
What are common cardiac diseases associated w/ Down’s syndrome?
AV defect, VSD, PDA (Patent Ductus Arteriosus)
What are common cardiac diseases associated w/ DiGeorge Syndrome?
Truncus arteriosus, TET (Tetralogy of Fallot)
What are common cardiac diseases associated w/ Holt-Oram syndrome?
Important features of Holt-Oram Syn.?
ASD, VSD;
Defects or absence of thumb or radius
What are common cardiac diseases associated w/ Marfan’s syndrome?
Important features of Marfan’s syn?
Aortic aneurysm, aortic regurgitation, and/or mitral regurgitation;
Arachnodactyly, subluxation of lens
What are common cardiac diseases associated w/ 1.Trisomy 13
- Trisomy 18
- Turner syndrome
- VSD
- VSD, PDA
- COA (Coarctation of Aorta (Narrowing)), PS (Pulmonary Stenosis)
What are the 3 major embryological processes contributing to the formation of the heart?
- Looping: Day 23-28 ( critical to the other 2 which happen simultaneously)
- Remodeling
- Septation
What is dextrocardia?
When the heart loops to the left instead of the right. This is not a problem itself, but is usually accompanied by additional severe defects (eg transposition of great vessels, and a single ventricle)
A person with dextrocardia w/ situs inversus will have what defects?
Usually none b/c all organs show this asymmetry (ie switched to other side)
What are the 4 ASDs and describe them.
- Ostium Secundum ASD: Failure of septum secundum to grow over foramen ovale (left>right shunting)
- Patent Foramen Ovale: Similar to above, a small patent foramen ovale is well tolerated
- Endocardial cushion defect w/ Ostium Primum ASD: A clefted mitral valve is often present
- Sinus Venosus ASD: Located in the superior portion of atrial septum near SVC opening
OPES
What is TAPVR or PAPVR?
Why must all cases need a ASD otherwise cyanosis will develop?
Partial/Total Anomalous Pulmonary Venous Return: All 4 for total(or less than 4 for partial) pulmonary v.’s do NOT connect to LA. They will usually connect to the RA in this abnormality, which directs oxygenated blood to RA and not to LA.
W/o an ASD, no oxygenated blood will go to LA, and cyanosis will develop.
Are ASDs or VSDs more common?
VSDs (25-30% of CHDs) compared to (6-10%) for ASDs
What are the 2 types of VSDs and describe them. Which one is most common?
- Membranous (most common): Caused by failure of an extension of subendocardial tissue to grow from the endocardial cushions and fuse w/ the aorticopulmonary septum and the muscular part of the IV Septum. Large defects cause massive left>right shunting, which can lead to CHF, and pulmonary hypertension.
- Muscular: Can even be as exterme as a single ventricle (ie total absence of IV septum) (3-chambered heart)
What does the formation of the aorta and pulmonary a. require w/ regard to the aorticopulmonary septum?
It requires spiraling of that septumb so that the pulmonary trunk originates ANTERIOR and to the right of the aorta.
Why are one of the causes of conotruncal, or aorticopulmonary septal defects defective neural crest cell migration?
B/c Neural crest cells contribute to the development of the truncal and bublar tissue including: aortic trunk, aortic arch, pulmonary trunk, ductus arteriosus, and membranous septum.
What is the most common cause of cyanosis?
Transposition of the Great Vessels/Arteries (TGA): THe spiraling of the aorticopulmonary septum did not occur at all, so aorta arises from RV, and Pulmonary trunk arises from LV.
What is Persistent Truncus Arteriosus (PTA)?
Failure of the truncal ridges of the aorticopulmonary septum to develop, resulting in ONE large vessels arising from the heart, emptying both R and L Ventricles.
NOTE: A VSD is always present here
What are the 4 “signs” (ie malformations) associated w/ tetralogy of fallot?
- Pulmonary a. stenosis
- VSD
- Overriding aorta: (aortic valve that connects to both ventricles)
- RV hypertrophy
Cyanosis and breathlessness will occur just after birth
PVOR
What is preductal coarctation?
Why is this defect not compatible with extrauterine life?
It is a constriction of the aorta proximal to the ductus arteriosus. This defect includes hypoplasia of the aorta and LV and is NOT compatable with extrauterine life b/c before birth blood can flow through the ductus arteriosus to the descending aorta but when it closes after birth then the condition of the infant rapidly deteriorates.
What is postductal coarctation?
Why is extrauterine viability possible?
More common than preductal, it is a constriction of the aorta distal to ductus arteriosus. During the fetal period, collateral circulation develops to compensate for this aortic arch anomaly which will allow the infant to be viable.
During fetal circulation, is left to right shunting a normal thing?
No; it should be right to left shunting. This of course stops after birth.
How does resistance in circulation change from the fetal pulmonary circulation to neonatal circulation?
It changes from a HIGH resistance to a LOW resistance circulation
Describe the closure of the foramen ovale.
Functional closure occurs at birth, ANATOMICAL closure occurs at 3 mo,
failure of ANATOMICAL closure results in a Patent Foramen Ovale (PFO)
Describe the closure of the Ductus Arteriosus.
Functional closure 1-2 hrs after birth, ANATOMICAL closure at 3 mo (12 wks).
Failure to close results in Patent Ductus Arteriosus (PDA) (common clinical sign is a machine-like murmur).
NOTE: The ductus arteriosus originates from the distal left 6th aortic arch, and connects the main pulmonary a. to the left descending aorta.
