Congenital Heart Disease Flashcards
What is a shunt?
A shunt is a transfer of blood from one side of the circulation to the other through an abnormal pathway.
What is the most common shunt at the atrial level?
Atrial septal defect - ASD
What is the most common shunt at the ventricular level?
Ventricular septal defect - VSD
What is the most common shunt at the ductal level?
Patent ductus arteriosus - PDA
What is the most common type of ASD?
Fossa ovalis or secundum type
What is the 2nd most common type of ASD?
Ostium primum type
What is the result of an ASD? (what is the orientation of the shunt)
The pressure in the left atrium is slightly higher than that of the right atrium and the compliance of the right ventricle is far greater than that of the left ventricle. Therefore, a shunt at the atrial level will produce volume hypertrophy of the right atrium and right ventricle with increased pulmonary flow and hemodynamic changes in the tricuspid and pulmonic valves.
Where do VSDs tend to occur?
Sub-atrially
What is the defect in ASD - secundum?
Fossa Ovalis
What are the changes in ASD - secundum?
L to R shunt
RA and RV hypertrophied and dilatated
What is the defect in ASD - primum?
Defect distal to Fossa Ovalis, close to the MV and TV
What are the changes in ASD - primum?
L to R shunt
RA and RV hypertrophied and dilatated
Cleft of MV
LV hypertrophy ONLY if there is mitral stenosis
What are the changes in VSD?
L to R shunt
RA hypertrophy
RV hypertrophy and dilation
This can lead to pulmonary HTN which would cause a R to L shunt causing:
LA hypertrophy and dilation
LV hypertrophy and dilation
What are the changes in PDA?
L to R shunt that increases pulmonary flow
Leads to LA and LV hypertrophy and dilation without pulmonary HTN and RA and RV hypertrophied and dilated as well
What are the changes in Isolated Pulmonary Stenosis?
No shunts
RA and RV with hypertrophy
Left side of heart is normal
What are the changes in Isolated Aortic Stenosis?
No shunts
LA and LV with hypertrophy
Right side of the heart is normal
What are the changes in Adult Coarctation?
Narrowing of the aorta in the region of the ligamentum arteriosum
No shunts
LA and LV hypertrophy
RA and RV are normal
What are the changes in Fetal Coarctation?
Long narrowing of the aorta with pulmonary HTN
RA and RV dilated with hypertrophy
LA and LV atrophy due to the non-constrictive narrowing of aorta which increases aortic pressure but not LV pressure
R to L shunt at ductus level
L to R shunt at atrial level
What are the 4 features of Tetralogy of Fallot?
- Infundibular Pulmonary Stenosis
- RV Hypertrophy
- VSD
- Overriding Aorta
What are the changes in Tetralogy of Fallot?
Large R to L shunt
RA and RV hypertrophy
VSD Characteristics
Hence, the most common type of a defect is called subaortic, in part membranous and in part perimembranous type. The complex is characterized by volume hypertrophy of the right ventricle, enlargement of the pulmonic orifice, hemodynamic changes of the tricuspid and pulmonic valves, volume hypertrophy of the left atrium and the left ventricle with enlargement of the mitral valve and hemodynamic changes in the mitral and aortic valves.
PDA Characteristics
In this entity, there is volume hypertrophy of the left atrium and left ventricle.
What is the likelihood of pulmonary HTN in ASD, VSD and PDA?
Thus, pulmonary hypertension may occur, most commonly in large ventricular septal defect, less commonly in patent ductus arteriosus and least commonly in atrial septal defect.
What is muscular type subaortic stenosis?
Hypertrophic cardiomyopathy is an autosomal dominant pattern of inherited genetic disease. Here there is asymmetrical septal hypertrophy of the muscular septum. This may produce subaortic obstruction and sudden death.
What is a sign of Tetralogy of Fallot?
U-shaped VSD
What is the more common type of Tetralogy of Fallot?
Cyanotic
What is Cyanotic T. of Fallot?
Here there is pressure hypertrophy of the right atrium and right ventricle with significant infundibular pulmonary obstruction. The left atrium and left ventricle have a tendency to be smaller than normal. The right ventricle is contracting against systemic and infundibular resistance, decreased pulmonary flow, and predominant right to left shunt at the ventricular level.
What is Non-Cyanotic T. of Fallot?
In acyanotic, tetralogy there is pressure and volume hypertrophy of the right ventricle, pressure hypertrophy of the right atrium, volume hypertrophy of the left atrium and left ventricle and enlargement of the mitral and aortic orifices. Here we are dealing with a left to right shunt at the ventricular level with increased pulmonary flow and increased volume to the left side of the heart.
