11/9 Congenital Heart Disease - Parang Flashcards
congenital HD
definition
- anatomic abnormality in cardiocirculatory structure/fx present at birth (even if discovered later)
- most common type of congenital defect (0.8% of all births)
- most cases: not certain what causes it
- genetic, environment, maternal illness, toxins all prob contribute
key congenital lesions
keys of fetal and transitional circulation
where is blood coming from? what are the relative levels of oxygenation?
what bypasses exist? why?
what happens to bypasses after birth?
recall:
- SVC contains poorly ox blood coming from head/upper extremities
- IVC contains relatively well ox blood coming from lower extremities (poor ox) and umbilical vein (HI OX!!!)
- umbilical vein is allowed to bypass liver and head straight into IVC through ductus venosus
- both drain into RA, but mixing is limited! → instead, blood heads in two diff directions
- IVC blood (hi ox) → foramen ovale to LA → LV → aortic arch → brain, etc
- SVC blood (lo ox) → RA → pulmo artery → ductus arteriosus in the desc aorta → to lower limbs!
three key bypasses
- ductus venosus → allows bypass of hepatic circ
- foramen ovale → allows oxygenated blood to bypass high-resistance pulmo circ
- ductus arteriosus → directs less-oxygenated blood to flow to lower extremeties
three shunts close after birth
- clamping the umbilical cuts off bloodflow through DV → DV closes
- baby breathes → lungs inflate → resistance drops AND L side pressure incr due to preferential flow through lungs → flow through foramen ovale drops → FO closes
- prostaglandins levels drop → DA closes
non cyanotic lesions
6 total
key feature
initially, there is NO R→L shunt
- atrial septal defect
- ventricular septal defect
- patent ductus arteriosus
- congenital aortic stenosis
- pulmonic stenosis
- coarctation of aorta
ASD
atrial septal defect
- distinct from PFO
- depending on location:
- secundum
- primum
- sinus venosus (SVC and pulmo v connection)
- normally a L→R shunt, with degee of sx depending on severity of shunt
- asymptomatic
- dyspnea
- palpitation
physical exam findings
- fixed split S2
- typically, incr bloodflow to the R side of heart on inspiration → delayed P2 on inspiration
- in ASD, no splitting! with inspiration, get the extra volume to to the R side, but the hole/defect allows you to equalize pressure through it, so no split
- evidence of RV enlargement (CXR/EDG/echo)
- “step up” in oxygenation in RA (compared to pulmo vein) [assessed via cardiac cath]
treatment
- depending on volume of shunting and presence of symptoms…
- surgical or percutaneous closure
- once you’ve got Eisenmengers…closure contraindicated
in general…
effect of one side of the heart seeing more VOLUME?
effect of one side of the heart seeing more PRESSURE?
volume → dilation (eccentric hypertrophy)
pressure → thickening (concentric hypertrophy)
VSD
ventricular septal defect
- most common locations: membranous or muscular ventricular septum
- normally a L→R shunt, BUT, they initially lead to LV volume overload! (not RV vol overload)
- blood is moved pretty quickly through the RV since they’re both contracting at same time…so the incr volume is mostly seen by LV and pulmo a
- over time: incr pulmo bloodflow → pulmo HTN & Eisenmenger’s syndrome
physical exam findings
- harsh holosystolic murmur
- possible evidence of left enlargement (CXR/EKG) or right enlargement if Eisenmenger’s
- sx of CHF: tachypnea, poor feeding, failure to thrive, freq upper resp tract infections
treatment
- depending on volume of shunting and presence of symptoms…
- surgical or percutaneous closure
- many close by themselves! (>50% of small/med size)
PDA
patent ductus arteriosus
- typically, PDA closes due to incr in O2sat and decr prostaglandins
- in postnatal circ, PDA stays open, and flow reverses: aorta → pulmo a
- L sided volume overload → dilatation
- risk factors: 1st trimester rubella, prematurity, high altitude
physical exam findings
- continuous “machine-like” murmur
- left enlargement (CXR/EKG)
- large shunts possible
- infants: CHF, tachycardia, slow growth, recurrent RTI
- adults: fatigue, palpitation, dyspnea
treatment
- CLOSE to reduce risk of endocarditis
- indomethacin
- surgery, percutaneous technique if indomethacin fails
- if you want to keep open…prostaglandin infusion!
congenital aortic stenosis
congenital aortic stenosis
- no shunting; aortic valve is just tight
- M > F
physical exam findings
- harsh crescendo-decrescendo murmur; loudest at base
- LV concentric hypertrophy (EKG)
- enlarged heart, dilated asc aorta (CXR)
- sx dependent on severity of stenosis
- infants: poor feeding, tachycardia, tachypnea, failure to thrive
treatment
- in infancy: balloon valvuloplasty (usually palliative)
- definitive tx: surgery
aortic stenosis is also potentially a result of bicuspid aortic valve (separate card)
bicuspid aortic valve
- common cause of aortic stenosis in adults due to progressive calcification of leaflets
- initially, not too bad
- over time, they get calcified more easily due to abnormal hemodynamics → can become stenotic
- strong assoc with coarctation of aorta, i.e. coarctation? → likely abnormal aortic valve
- HOWEVER, opp is not true. abnormal aortic valve? not more likely to have coarctation of aorta
presentation and management is similar to calcific aortic valve stenosis
- key diff: stenosis due to bicuspid valve presents younger than regular old calcific variety
pulmonic stenosis
pulmonic stenosis
- in valve (90%), within RV, within pulmo a
-
causes: incr RV pressure, hypertrophy
- mild (<50mm), mod (50-80mm), or severe (>80mm)
physical exam findings
- prominent jugular a wave
- late-peaking cresc-decesc murmur at L upper sternal border
- pulmonic valve click: ONLY R sided sound that decreases with inspiration
- most R sided heart sounds increase with inspiration
- enlarged RV
- sx of R sided heart failure: edema, abd fullness
- dyspnea on exertion, exercise intolerance
treatment
- balloon valvuloplasty
coarctation of aorta
coarctation of aorta
- assoc with Turner Syndrome (XO)
- results in pressure overload of LV
physical exam findings
- LVH, enlargement of intercostal arteries to bypass site of coarctation
- EKG: LVH
- CXR: intercostal notching on posterior ribs
- weak, delayed femoral pulses
- differential bp in upper/lower extremities (depending on site of coarct)
- severe cases: infants with differential cyanosis
treatment
- infants: maintain PDA with prostaglandin infusion to keep lower ext perfusion intact
- elective repair to prevent systemic HTN (less severe cases)
- surgical or percutaneous balloon dilatation
cyanotic lesions
R→L shunting
- Tetralogy of Fallot
- transposition of great arteries
tetralogy of Fallot
interventricular septum positioned anteriorly and superiorly to where its supposed to be (abnormal anterior and cephalad displacement of infundibular portion of intraventricular septum)
- subvalvular pulmonic stenosis
- RVH
- ventricular septal defect
- overriding aorta: aorta overrides septal defect
net result: R→L shunt through VSD, resulting in cyanosis
- “spells” made worse on exertion, made better on squatting (incr vascular resistance → reverse shunting)
physical exam findings
- cyanosis
- clubbing (chronic finding)
- pulmonic systolic ejection murmur
- CXR: “boot shaped” heart
- ECG: RVH
treatment
- surgical closure of VSD and enlargement of subpulmo infundibulum
- may need repeat operation as adults to replace pulmonic valve
transposition of great arteries
- aorta coming off RV, pulmo a coming off LV
- as a result, systemic and pulmonary circulation end up being in parallel (instead of in series)
- baby fine in utero. why? R→L shunt!!!
- postnatally, though, need some type of mixing to occur to sustain life: want PDA or an ASD
treatment
- initial tx: maintain PDA with prostaglandin infusion or creation of interatrial communication through balloon catheter
- definitive correction: “arterial switch” procedure
anomalous coronaries
1 uncontroversial situation
1 controversial situation
everything else (uncontroversial)
L main off R cusp coursing between pulmo artery and aorta associated with sudden death
- corrected with bypass surgery
- uncontroversial
R coronary coursing between great vessels
- bypass vs observation
- choice depends on sx, but this is controversial
everything else: observe!
CHD associations
memorize.
