Cyanotic CHD Flashcards
Truncus arteriosus
Cyanotic CHD with increased PBF - outflow tract defect
Common PA + Ao
VSD always present - LV/RV mixing
+/- interrupted aortic arch 13%, R) aortic arch 30%
Failure of neural crest cells to migrate to bulbus cordis (septation to form Ao/PA)
Associations: DiGeorge (22q11) 30%
Pathophysiology
- Both ventricles eject blood at systemic pressure
- Increased PBF
- CCF features within 2wks of life
- Develop pulmonary HTN & PVOD by ~3-4mo
Features
Single S2
Ejection systolic murmur LUSB
Continous systolic murmur of VSD
+/- apical diastolic rumble (increased flow across MV)
ECG: BVH, LAH
CXR: cardiomegaly, increased pulmonary vasculature
Treatment
Diuretics, CCF treatment
Surgical- conduit betwern RV/PA
Transposition of great arteries (TGA)
Cyanotic CHD + increased PBF
- *D-TGA**
- Ventricles in position, vessels switched
- Ao drains RV, PA drains LV
Associations: VSD 30-40%
- *Pathophysiology**
- Lungs- oxygenated blood
- Systemic- deoxygenated blood
- Circuits seperated, requires mixing to survive (without VSD = sickest)
- If VSD only develop PVOD
- If VSD + PS = best survival
Features
Cyanosis (less if VSD)
Tachypnoea
Single & loud S2, holosystolic murmur LLSB +/- mid-systolic murmur
ECG: RVH/RAH +/- LAH
CXR ‘egg on a string’
Treatment
PGE1
Balloon septostomy to preserve PDA if inadequete mixing
Arterial switch 1-2wks of life
(Cx CA obstruction, supravalvular PS, valvular regurgitation from neo-Ao)
- *L-TGA (congenitally corrected)**
- Physiological
- RV on LHS, Ao drains RV
Associations: VSD 80%, PS 50%, TR 40%m dextrocardia 50%
- *Pathophysiology**
- Asymptomatic without other defects
- With VSD/PS = cyanotic, CCF if large
- Can have AV conduction disturbance
- *Features**
- Cyanosis, loud S2, holosystolic murmur LLSB
- ECG: absence of Q wave in V5-6, Q wave in V1, upright T waves, AV block +/- WPW
- CXR: L) straight upper cardiac border, cardiomegaly/increased lung markings if VSD, dextrocardia
Treatment
Conservative: manage CCF, antiarrythmics
Surgical repair- high risk CHB
Tricuspid atresia
Cyanotic CHD with decreased PBF
Tricuspid valve malformed, or fails to develop entirely
- No connection between RA/RV
- Hypoplastic RV
Incompatible with life without ASD/VSD
Associations: PS, TGA, coarctation
Pathophysiology
RA → ASD/PFO → LA → LV
- VSD → RV → lungs
- Ao → systemic
- Single ventricle pathology as LV supports entire blood volume
Features
If PS = reduced PBF, cyanosis
If large VSD = CCF
Death within 6mo without treatment
Cyanosis
LV impulse
Holosystolic murmur LLSB (VSD)
Machinery murmur if PDA
Apical diastolic rumble if MR
ECG: RAH/LAH, LVH, Superior axis
CXR: Concave pulmonary artery, reduced pulmonary vasculature
Treatment:
PGE1 if no VSD
Fontan
Tetralogy of Fallot (TOF)
Outflow tract defect
Most common cyanotic defect
- Pulmonary stenosis/ RVOT obstruction
- Hypertrophied RV
- VSD
- Displaced/overriding aorta
Infundibulum tissue
Level of cyanosis depends on severity of pulmonary stenosis
Associations (~15%): Di George 22q11, Down’s syndrome, Allagile syndrome
Pathophysiology
Severity of RVOT obstruction determines shunt
- Mild = L→R (pink TOF)
- Severe = R→L (cyanotic TOF)
- Also depends on SVR vs PVR
TOF + Pulmonary Atresia: pulmonary blood flow via PDA/MACPAs
TOF + pulmonary vessel hypoplasia: 2% RV/PA dilatation, PR, compression of trachea & bronchi
Features
Cyanosis if severe RVOTO, moderate murmur & tet spells, mild CCF later in childhood
Early mortality <2yrs if assoc PA - haemoptysus from collateral vessels
High mortality with absent PV >20%
‘Tet spells’
Crying, defecation, increased activity- increases cardiac demand/CO - decreases output, increased R→L shunting, desaturation & quieter murmur
Tachypnoea worsens cyanosis
Squatting/bending legs, kinks arteries, decreased SVR
RV tap LLSB
Ejection systolic murmur -RVOTO
Machinery murmur- PDA
Single S2 (absent PV/PS)
Murmur decreases with increasing severity
Ejection click, loud S2 in TOF + PA
To and fro murmur if absent PV
ECG: R) axis deviation, RAH, RVH
CXR: ‘boot shaped heart’
Treatment
Conservative/temporising
- Morphine, oxygen
- Vasoconstrictors, B-blockers (propanolol)
Surgical
- BT shunt if decreased PBF
- PA banding if increased PBF
4-6mo for definitive, 1-2yrs if mild
1. VSD patch closure
2. Widening of RVOTO
3. Pulmonary valvulotomy
TOF + PA
PGE1 dependant
Shunt operation required
Total anomalous pulmonary venous return (TAPVR)
Cyanotic CHD with increased PBF
PV drains into alternative site, no connection with LA
- Systemic veins: Supracardiac 50%, infracardiac 20%, cardiac 20% (RA), mixed 10%
- Requires ASD/PFO for survival
Pulmonary veins develop close to lungs then grow toawrds heart to fuse with LA, fuse at wrong location
Mixing occurs in R) heart
RV → pulmonary circulation → ASD/PFO → systemic
Without obstruction = RA/RV overload, net L → R shunt, elevated PBF
With obstruction = pulmonary HTN, systemic hypoperfusion
Without obstruction = CCF, pumonary infections
With obstruction = cyanosis, respiratory distress, death
Cx: pulmonary HTN
Features
Without obstruction
Not cyanotic
Hyperactive RV, widely split S2, S3-S4 present
Systolic murmur LUSB (PS), mid-diastolic LLSB (TS)
ECG: RVH
CXR: cardiomegaly, RAH/RVH
With obstruction
Cyanotic ++
Tachypnoea
Loud single S2, gallo rhythm
Hepatomegaly, pulmonary crackles
ECG: RAD, RVH
CXR: normal sized heart, pulmonary oedema
Treatment
Ventillatory + fluid volume support
PGE can worsen pulmonary circuit overload
Obstruction- immediate surgery
No obstruction- surgery 4-6mo
Outflow tract defect- embryology
Truncus arteriosis
Bulbus cordis - neural crest cells migrate and promote septation to form Ao/PA
Incomplete formation of aorticopulmonary septum = persistent truncus arteriosis
Defect in spiralling of aorticupulmonary septum = TGA
TOF
