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Cyanotic heart

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How is cyanosis due to congenital heart disease clinically differentiated from other causes?
By giving oxygen. If kid responds, its not cardiac cause. O2 will not help much, since respiration is not the source of the problem.
What can happen if you give a kid with acyanotic heart dz (L -- R) shunt o2?
Can make situation worse, by increasing shunt by reducing pulmonary bed resistance.
What are other vascular non-cardiac causes for cyanosis?
Osler-Weber-Rendu, with multiple pulmonary AVMs.



Hepatic pulmonary angiodysplasia: Occurs anytime systemic venous blood that has purely been unexposed to liver is put through the pulmonary bed.
When does this occur?
After the Glenn (second step in repairing hypoplastic left heart), when blood is shunted from SVC directly into the right pulm artery, they can get angiodysplasia of right lung, which results in A-V shunting and cyanosis.
What is the first radiological step when encountered with a patient who is cyanotic?
Frontal CXR
What are you looking for?
Noncardiac causes for cyanosis.
Such as?
Pulmonary consolidations


Pneumothorax


Congenital diaphragmatic hernia


Mass lesions with mediastinal shift (including congenital lobar emphysema).
What patterns of pulmonary vascularity are seen in cyanotic heart dz?
Increased


Decreased


Normal
When are they increased?
Admixture lesions
When is it decreased?
Pulmonary vasculature obstructive lesions (with r - l shunt, as no decrease will be seen if there is no shunt, i.e. isolated pulmonic stenosis)
Appearance of decreased bloodflow on CXR:
In newborns, who already have low bloodflow through pulm circuit, lungs normally look oligemic. Can detect true pulm oligemia by seeing lung that just looks too clear/dark.
What are signs of increased pulm blood flow on CXR?
1) Interlobar artery larger than trachea


2) Tortuosity of vessels seen through liver shadow


3) 2nd-3rd order vessels larger than their corresponding bronchi
Tracheal position on CXR:
A truly normal trachea is deviated toward the right slightly by the left aortic arch. If you see a kid with truly midline trachea, think about right sided arch.
What lesion most commonly has right sided arch?
Truncus arteriosus
What percent?
40% with truncus have R arth
What lesion has R arch second most commonly?
Tetralogy
What percent with tet have R arch?
30%
What are the two classes of cyanotic heart disease?
1) Right heart obstruction


2) Admixture lesions
R heart obstructive lesions:
Blood is prevented from easily getting to pulm circuit, and then gets shunted back to left side since it has to go somewhere
Admixture lesions:
Shit is going everywhere.

There is R to L shunt resulting in oligemia, as well as L to R shunt, resulting in pulm overcirculation.
Appearance of R atrium:
Broad triangular appendage


Coarse trabecular pattern
Appearance of L atrium:
Long, fingerlike appendage
Appearance of RV?
Triangular shape, with inlet (tricuspid valve), apex, and infundibulum each representing one corner.



Coarse trabeculae c 3 papillary muscles


From the inferior (basal) septum to the free wall runs a thickened muscular band = moderator band
Appearance of LV?
Oval shaped


No thick trabeculae


Two distinct papillary muscles. No septal papillary muscle.



No space between mitral valve and aortic valve (like there is between tricuspid and RV outflow tract)
What are the components of TOF?
1) Pulmonic stenosis


2) Overriding aorta


3) VSD


4) RV hypertrophy
What are the admixture lesions?
5 T's and CAD
What are they?
Tricuspid atresia



Transposition (D-transpo)



Truncus



TAPVR



"Tingle" = single ventricle



Common atrium



Aortic atresia (Hypoplastic left heart)



Double outlet ventricle (DORV)
What is transposition?
Anomalous alignment of the ventricles with the great vessels
What is a complete transpo?
Means that each ventricle is aligned perfectly with one great vessel, its just the wrong one. A morphologic right ventricle exhausts into the aorta. A morphologic left ventricle exhausts into the pulmonary artery.
What is an incomplte transpo?
Occurs when the great vessels are not separated and one ventricle (usu right) gets to exhaust into both the aorta and PA (=DORV)
What is true of complete transpo?
Atrioventricular CONCORDANCE (LA opens into LV, RA into RV)


AND



Ventriculoarterial DISCORDANCE
What is required for survival?
Some shunt. ASD, VSD, PDA or multiple of those.
Where is the aortic valve normally in relation to the pulmonic valve?
To the RIGHT, INFERIOR, and POSTERIOR of the Pulm valve.


(YOU KNOW ITS TO R, by seeing on CT all the time. YOU KNOW ITS POSTERIOR, since you know PA is more anterior than aorta. Only thing you have to remember is that its also INFERIOR).
What happens in TGA?
Valves switch positions, so now the aorta comes off way anteriorly, and thus has a longer transverse portion as it arches posteriorly full of deoxygenated blood.
What is special epidemiologically about TGA?
Most common cyanotic heart dz presenting in the newborn period
Plain film appearance of TGA:
Plain radiographs may be normal in D-TGA given the absence of a large volume load on the pulmonary bed. This is especially true in neonates.


In patients with larger admixture connections between the two circuits, increased vascularity may be apparent.


An "egg-on-a-string" appearance to the heart is described as classic: there is mild cardiomegaly and a narrow mediastinal waist, due to stress involution of the thymus and absence of the usual main pulmonary artery bulge along the left mid mediastinum. This latter finding is due to a rightward/central orientation of the main pulmonary artery as it arises from the left ventricle, thus it no longer is border forming.
What is corrected transposition?
There is still ventriculoarterial discordance, but there is also atrioventricular discordance. The atria stay put (thus there is normal situs, since situs is determined only by atrial position) but the ventricles are flipped, hooking up with the wrong atria, taking with them their discordant arterial connections. Thus the ventricles end up being the only thing out of place, as each atrium connects up to its correct great vessel This gets rid of the parallel circuits of complete transposition, and the patient will be asymptomatic.
What are TOF and truncus both examples of?
Conotruncal anomaly.
What are conotruncal anomalies associated with?
DiGeorge syndrome
What are the two primary symptoms in truncus?
1) Cyanosis


2) Severe pulmonary overcirculation, resulting in pulm congestion.
What are the types of truncus?
I - IV
What is type I?
branch pulm arteries come off truncus just above truncal valve
II?
Branch pulm arteries come off truncus in its ascending portion, and are positioned right next to each other.
III?
Branch pulm arteries come off truncus in its ascending portion, but are on opposite sides of the truncal artery from each other
IV?
= PSEUDOTRUNCUS



Complete pulmonary atresia with large collateral feeders to the lungs from the descending aorta.
Where is the MAIN site of admixture in a truncus?
In the large nonrestrictive VSD which is always present. Of course more mixing occurs inevitably later on in the truncal vessel.
What is TAPVR?
Embryologically, the pulmonary veins do not connect up with the left atrium, thus outflow from lungs ends up somewhere else.
What is PAPVR?
At least one of the pulm veins does go back to the LA, but the other ones end up somewhere else.
What is the most famous version of this?
Scimitar syndrome
Back to TAPVR: How many types are there?
3
What are their names?
Supracardiac


Cardiac


Infracardiac
What is supracardiac?
The common pulm vein (this defines TAPVR -- all 4 pulm veins come together and form a single common pulm vein) flows superiorly along the left mediastinum, to anastomose with the left subclavian or innominate vein. From there it flows back to the SVC into the RA.
What is the appearance on x-ray?
SNOWMAN
What is the cardiac TAPVR?
Common vein dumps into the coronary sinus
What is infracardiac?
Common vein goes through esophageal hiatus where it joins portal vein, ductus venosus, hepatic vein or IVC.
What is required in TAPVR? Why?
ASD or patent foramen ovale.


Because all blood is returning to the RA, so have to get some over to the left. This is why the cyanosis occurs. You are perfusing the tissues with admixed blood.
What is scimitar syndrome?
1) PAPVC to right atrium or IVC


2) Right pulmonary hypoplasia with variable hypoplasia of the right lung


3) Rightward shift of the heart



4) Anomalous systemic arterial supply to the right lung
What makes a single ventricle?
Both AV valves align with one ventricle, thus all blood flows into and admixes in a single ventricle.
What is another name for complete transposition?
D
What is another name for corrected transposition?
L

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