Heart Folding
Right (d-looping) causes the atrium and sinus venosus to migrate cranially; neural crest cells by this point have participated in Aorticopulmonary septation and helped form the primitive aortic arches
(Roughly week 4)
What forms the borders of the AVC?
Cardiac jelly, fusion of superior and inferior endocardial cushions
=»Endocardial cells then differentiate to form the fibrous portion of the valves
3 origins of the membranous part of the IVS
Right bulbar ridge, left bulbar ridge, and the av septum (endocardial cushions)
By what day does the heart have 4 chambers
50
1st aortic arch =»
Maxillary and external carotid arteries
Third aortic arch =»
Common carotid artery
Fourth aortic arch =»
Left= aortic arch; right=subclavian
Sixth aortic arch =»
Right= RPA/LPA; Left= Ductus arteriosus
Pulmonary Vein development
Lung buds from the embryonic foregut incorporate a common vein to the left atrium at week 8 and separate into two distinct veins by week 12
What does the sinus venosus become?
The smooth part of the RA
Atrial Septal Defect
Leads to right atrial enlargement, right ventricular enlargement, and increased pulmonary flow
Clinical: Soft systolic ejection mumur at the left upper sternal border, fixed split S2, and prominent RV impulse
CXR may show cardiomegaly; echo is gold standard
Tx: May close spontaneously or can close w/ cardiac catheterization procedure
Ventricular Septal Defect
Most common congenital heart disease
Blood flows from LV to RV causing increased pulmonary flow, some LV enlargement, and LA enlargement
Signs:Presents at ***4-8 weeks w/ tachypnea, diaphoresis, failure to thrive
PE: Hyperdynamic precordium, holosystolic mumur at lower left sternum, possible mid-diastolic rumble at the apex w/ large defects
Tx: Surgery
PDA
Common in preemies; decreased pulmonary resistance at birth causes L=>R shunting increasing return and leading to LA and LVL enlargement
Signs: Tachypnea, diaphoresis
PE: Harsh, machine-like murmur at the upper left sternal border, tachypnea
PDA: Indomethacin, cardiac catheterization procedure
Atrioventricular Septal Defect
Partial defect is similar to ASD, complete defect has combination of ASD and VSD (severe)
Clinical: Partial =» asymptomatic; Complete =» CHF signs
PE: Partial- Fixed S2 impulse, systolic ejection murmur at upper left sternal border
Complete-Loud S2, hyperdynamic precordium, murmur at lower-left sternum
Tx: Partial- Observation, elective surgery when older
Complete- Management of CHF, surgery at 3-6months
Aortic coarction
Commonly seen in Turner’s Syndrome (XO); causes a rise in EDV leading to increased LV and LA pressures and pulmonary edema
***HTN in upper extremities; hypotension in lower extremities
PE: CHF signs once ductus arteriosus closes; possibly mild HTN in older children
Tx: PGE1 to maintain ductus arteriosus, inotropy support, correction of metabolic acidosis
Hypoplastic Left Heart Syndrome
Self-described; causes a dominant right heart and causes things light aortic atresia/stenosis alongside mitral atresia/stenosis depending on the size of the LV
-While Ductus arteriosus is open, some blood from the pulmonary artery will enter systemic circulation
PE: Shock once PDA closes but mild cyanosis before that; usually seen prenatally
-Dyspnea, single loud S2
Tx: PGE1, inotropy help, hypoventilation to manage pulmonary resistance
-Eventual severe surgery is performed connecting the IVC to the pulmonary artery (FYI)
Tetrology of Fallot
PROVe
-Initially a L=>R shunt due to V, hypertrophy of RV and increased pulmonary stenosis eventually changes it to R=>L shunt
PE: Normal S2, cyanosis, harsh systolic ejection murder on left sternal border that radiates to the back
*HYPERCYANOTIC EPISODES: acute increase in R=>L shunting that causes cyanosis, irritability, lethargy, hyperpnea
=»Put baby in knee-chest position to decrease VR and increase SVR (goal is to improve pulmonary flow)
-Also give IV fluids (increased pulmonary flow), morphine, phenylephrine, BB
***Boot-shaped heart on CXR
Tx: Surgery
Tricuspid atresia
Pts. have interatrial communication, hypoplastic right ventricle, and a VSD
-Systemic venous return mixes w/ pulmonary return in LA, all pulmonary flow must go across the VSD and degree of cyanosis depends on this flow
PE: Neonatal (early) cyanosis, normal S2, left ventricular impulse
Tx: PGE1, surgery
Transposition of the Great Vessels
Assoc. w/ patent foramen ovale, VSD, and aortic coarction; degree of mixing of blood determines cyanosis
PE: Neonatal cyanosis, may be a murmur
Tx: PGE1, surgery
Truncus Arteriosis
Assoc. w/ 22q.11 deletion; pulmonary blood flow depends on resistance
PE: CHF, mild cyanosis, holosystolic murmur from VSD
***ONLY DISORDER TO HAVE A DIASTOLYLIC MURMUR TOO (from truncal regurgitation)
Total Anomalous Pulmonary Venous Return
Assoc. w/ hetortaxy syndrome; Pulmonary arteries connect back to the RA; systemic flow depends on patent foramen ovale or ASD
PE: Unobstructed-Asymptomatic initially, then feeding problems, tachypnea, failure to thrive, widely split S2, systolic murmur
Obstructed- Severe respiratory distress and cyanosis on 1st day of life, normal cardiac signs
-Snowman sign on CXR, echo
Tx: Unobstructed- Medical therapy then surgery
Obstructed- SURGICAL EMERGENCY; stabilize (inotropics, PGE1, mecahnical ventilation) and surgery