8. Congential Heart Defects Flashcards
What can cause congenital heart defects?
Genetic: Downs, Turners, Marfan’s, or polygenic
Environmental: drugs, alcohol
Maternal infections: rubella, toxoplasmosis
What happens in a left to right shunt?
Blood from left heart is returned to lungs instead of going to body
Requires a hole
Why is a left to right shunt bad?
Increased lung blood flow by itself I’d not damaging, but increased pulmonary artery or pulmonary venous pressure is
What is a right to left shunt?
Requires a hole and distal obstruction
Deoxygenated blood bypasses the lungs
What are the 2 classes of congenital defects?
Acyanotic - pink
Cyanotic - blue (circulating blood deoxygenated)
What are the acyanotic congenital heart diseases?
Left to right shunts (ASD, VSD, PDA)
Obstructive lesions: aortic stenosis, pulmonary stenosis, coarctation of the aorta, mitral stenosis
What are cyanotic congenital heart defects?
Complex, right to left shunts Tetralogy of fallot Transposition of great arteries Total anomalous pulmonary drainage Univentricular heart
What shunts may be present?
Atrial
Ventricular
Atrioventricular
Aortopulmonary (ductal)
Where can atrial septal defects be?
Sinus venous
Secundum atrial
Primum atrial
What are the haemodynamic effects of atrial septal defects?
Increased pulmonary blood flow (low pressure)
RV volume overload
Sometimes pulmonary hypertension
Eventual right heart failure
What are the haemodynamic effects of ventricular septal defects?
Left to right shunt
LV volume overload
Pulmonary venous congestion
Eventual pulmonary hypertension
What is coarctation?
Aortic narrowing that occurs at or near the aortic arch
What makes up a tetralogy of fallot?
Ventricular septal defect
Over-riding aorta
Pulmonary stenosis
Right ventricular hypertrophy
What is tricuspid atresia?
No RV inlet
R to L atrial shunt of entire venous return
Blood flow to lungs via VSD or PDA
What is transposition of the great arteries?
RV connected to aorta
LV connected to pulmonary artery
Not viable unless the two circuits communicate i.e. via atrial, ventricular or ductal shunts
Bi directional shunting
What is hypoplastic left heart?
Left ventricle is underdeveloped Ascending aorta very small Right ventricle supports systemic circulation Obligatory right to left shunt Must be ASD and PDA
What is pulmonary atresia?
No RV outlet
R to L atrial shunt of entire venous return
Blood flow to lungs via PDA
What is the natural history of ASD?
Usually asymptomatic late into adulthood
Lat onset arrhythmia and right heart failure
What is atrial history of VSD?
Unless very small, present in infancy with left heart failure
Untreated, can lead to in-operable pulmonary hypertension
What is the neural history of coarctation?
Neonatal variety: associated with PDA, R to L shunt
Adult variety: complicated by renal hypertension, often associated with aortic valve stenosis
What is natural history of tetralogy of fallot?
Present in infancy or early childhood with cyanotic spells
Mild cases compatible with adulthood
Which congenital heart diseases present as neonatal emergencies from reduced pulmonary blood flow?
Transposition
Hypoplastic left heart
Pre-ductal coarctation
Pulmonary atresia
