Congenital Heart Disease

Question 1

Pulmonic Stenosis

Answer 1

epidemiology

• congenital, often ass w/ other cardiac lesions

pathophysiology

• stenosis of valve or RV infundibulum => increased resistance to RV outflow => increased RV pressure and limits pulmonary blood flow
  anatomy:
• valvar > subvalvar > supravalvar

relevant genetic factors

DX

• Echo/Doppler
  
  • show doming valve vs dysplastic valve
  • subvalvular obstruction
  • presence or absence of tricuspid or pumonic regurg
  • gradient across valve (mild - <30 mmHg; moderate - b/n 30 and 60 mmHg; severe - >60 mmHg)
• ECG
  
  • R axis devation = RVH
  • peaked P waves = RA overload
• CXR
  
  • NL heart size or enlargment grossly, RA, or RV
  • often postenotic dilation of main and L pulm arteries
  • Ca may be present in pulm arteries

S:

• mild = asx
• moderate/severe = DOE, syncope, CP => RV failure and low CO

O:

• • palpable parasternal lift d/t RVH
• • loud, harsh, systolic murmur and occassionally prominent thrill at L 2nd and 3rd ICS
    
    • radiates to L shoulder (as due to flow pattern)
    • increased w/ inspiration
• mild to moderate = loud ejection click preceding murmur (follows S1- systolic)
  
  • decreases w/ inspiration (as RV filling from inspiration prematurely opens valve during systole-diminishes w/ more V ejected into RV during inspiration)
• S2 often obscured by murmur - P2 diminshed, delayed, or absent
• R sided S4 and prominent a wave in JVP w/ RV diastolic dysfunction
• severe = cyanosis (also in patent foramen ovale w/ R to L shunting)

general management approaches

• mild = NL life span w/o intervention
• moderate = sxs often appear when older
• severe = can cause R HF in 20 and 30 yo
• SBE (subacute bacterial endocarditis) prophylaxis (rare)
• balloon dilatation or sx if severe
• valve replacement (in obstruction)

Question 2

Coarctation of the aorta

Answer 2

epidemiology:

• ass bicuspid aortic valve (50-80%)
  pathophysiology:
• = localized narrowing of aortic arch just distal to origin of L subclavian artery
• develops related to accessory ductal material that contracts soon after birth, so not in fetus
• depends on degree of narrowing and ass lesions
• collateral circulation develops around coarctation thru intercostal arteries and branches of subclavians => lower transcoarctation gradient by allowing blood flow to bypass obstruction

anatomy:

• preductal (long segment, fetal onset)
• postductal (short segment, postnatal onset) (more common)

DX:

• Echo/Doppler
  
  • gradient >20 mmHg
  • bicuspid arotic valve
• ECG
  
  • LVH
• CXR
  
  • scalloping of ribs d/t enlarged collateral intercostal arteries
  • dilation of L subclavian atery and postenotic aortic dilation and LV enlargement
  • “3” sign along aortic shadow on PA CXR
• MRI and CT = images of anatomy

S:

• if no CF in infancy, no sxs until HTN produces LV failure or cerebral hemorrhage occurs

O:

• systolic HTN upper body w/ diminished lower body pulses (BP difference >15-20 mmHg) [diastolic similar BPs]
• strong arterial pulses in neck and suprasternal notch
• HTN in UE, BP NL or low in LE
• difference exaggerated by exercise
• weak and delayed femoral pulses compared to radial or brachial
• continuous murmur heard superiorly and midline in back or over L ant chest may be present when collaterals carry a lot of flow
• systolic ejection murmurs at base, often heard posteriorly ​

TX:

• preductal = prostaglandin E to keep ductus open, if sxs neonate or sx
• postductal = transcatheter balloon dilatation or stent implantation or sx
• pts HTN even s/p sx because of changes in renin-angiotensin pathway, endothelial dysfunction, aortic stiffness, altered arch morphology, and increased ventricular stiffness

Complications

• CHF, endocarditis, dissection, stroke

Question 3

Atrial Septal Defect/ Patent foramen ovale

Answer 3

anatomy:

• septum primum separates the atris, moving inferiorly and ventricular septum forms moving superiorly at same time
  
  • if atrial septum does not make it all the way, residual defect in septum primum = primum ASD (ostium primum)
• if septum primum makes it, a hole(s) forms in middle of septum (creating ostium secundum)
• a second septum forms and moves down R side of septum and covers ostium secundum hole
  
  • if it doesnt cover the hole = secundum ASD
• septum secundm normally completely covers R side of atrial septum except for ovale defect in it inferiorly (foramen ovale)
• if septeae do not fuse =>patent path from RA to LA persists (PFO)
• most common = persistence of ostium secundum in mid septum
• in ostium primum defect - mitral or tricuspid valve redundacy or clefts as well as VSD as part of AV septal defect
• 3rd form of ASD = sinus venosus defect (hole at upper or lower part of atrial septum due to failure of embryonic SVC or IVC to merge w/ atri properly)
  
  • SVC sinus venosus defect commonly ass w/ anomalous connection of R upper pulmonary vein into SVC

pathophysiology:

• in all cases, normally O2 blood from higher pressure LA passes into RA, increasing RV output and pulm blood flow
• as RV diastolic P increases from chronic V overload, L to R shunting decreases and eventually RA P exceeds LA P and R to L shunting occurs primarily => systemic cyanosis
  
  • major factor in direction of shunt flow = compliance of respective atrial chambers
  • size of hole
  • pulm/systemic resistances
• usually = L to R shunt w/ R sided V overload
• pulm P only modestly elevated
• eventual RV failure may occur

S:

• asx until late
• palpitations (atrial arrythmias- d/t RA enlargment)
• larger ASD shunts = DOE, HF develop in 40s or later

O:

• loud systolic ejection murmur at 2nd and 3rd ICS (from increased flow thru pulm valve)
• tricuspid mid-diastolic rumble (large L to R shunts due to high flow across tricuspid valve)
• wide and fixed split S2 (no variation w/ respiration)
• RV lift

DX:

• CXR = large pulmonary arteries, increased pulmonary vascularity, an enlarged RA and RV, and a small aortic knob with all pre-tricuspid valve cardiac L to R shunts
• Echo
  
  • RA and RV V overload
  • atrial defect observed
  • CT and MRI to visualize anatomy of defect

TX:

• percutaneous device or surgical closure (if evidence of RV V overload, hypoxemia evidence)

Complications:

• A fib d/t RA enlargement
• late dysrhythmia or pulm HTN
• paradoxical R to L emboli (uncommon)

Question 4

Ventricular Septal defect

Answer 4

epidemiology:

• common (25% of all congenital)
• de novo in adults is umcommon
• presentation in adults dependent on size of shunt and if there is ass pulmonic or subpulmonic stenosis that has protected lung from systemic P and V
  
  • unprotected w/ large defect => severe pulm HTN and pulm vascular disease d/t chronic V overload from large L to R shunt= Eisenmenger physiology
    
    • pulm resistance > systemic = cyanosis, clubbing, polycythemia

pathophysiology

• occur in various parts of ventricular septum
  
  • type A = VSD lies underneath semilunar valves
  • type B = VSD is membranous w/ 3 variations
  • type C = inlet VSD is present below tricuspid valve and often part of AV canal defect
  • type D = muscular VSD
• membranous and muscular may spontaneously close during childhood
• L to R shunt (unless ass RV HTN) depends on:
  
  • size of defect (smaller = greater gradient from LV to RV=> louder murmur)
  • relative pulmonary and systemic vascular resistances

S:

• depend on size of shunt and presence or absence of RV outflow obstruction or increased PVR
• V overload LA and LV (now R to L shunt) => SOB, fatigue, CHF, poor growth, pneumonia

O:

• small shunts
  
  • loud, holosystolic murmur in L 2rd and 4th ICS along sternum
  • systolic thrill common
• larger shunts
  
  • RV V and P overload
  • if pulm HTN, high P pulm regurg may result
  • R HF may gradually become evident and shunt will equalize or reverse as RV and LV systolic P equalize w/ pulm HTN
    
    • cyanosis from R to L shunting then

DX:

• ECG
• CXR = large shunts, RV, LV, LA, and pulm arteries are enlarged and pulm vascularity is increased
• Echo and Doppler !
• MRI/CT

Complications

• poor growth
• lung infections
• pulm vascular disease (Eisenmenger’s)
• endocarditis

TX:

• spontaneous closure (25%)
• medical tx if small shunt
• sx if pulm blood flow > 2x NL

Question 5

Tetrology of Fallot

Answer 5

epidemiology:
* 10% of congenital defects
features:

• RV outflow obstruction from infundibular stenosis (at, below/or above valve)
• RVH (develops as result of increased workload of RV)
• VSD
• overriding aorta (dilated and overrides septum) (receives blood from RV and LV)

pathophysiology

• RV outflow obstruction and relative pulm and systemic resistances => R to L shunt across VSD into overiding aorta => hypoxemia and cyanosis
• pulm artery is narrowed, limiting amt of blood entering lungs to become oxygenated
• RV attempts to overcome obstacle in outflow tract through pumping more blood = RVH
• venous blood in RV cannot enter narrowed PA and is shunted thru VSD into aorta
• mixing of RV and LV blood facilitated by overriding aorta
• aorta can be filled w/ blood from both and will contain venous and aterial blood

S/O:

• in adults, can be diminished RUE pulse on side used for Blalock procedure
• JVL may reveal increased a wave from poor RV compliance
• persistant pulm outflow murmur
• P2 may or may not be audible
• maybe R sided gallop heard
• residual VSD or aortic regurg murmur heard maybe

Complications

• “Tet spells” = systemic vasodilatation (exercise, orthostasis, fever) => increase R to L shunt => cyanosis and cerebral hypoxia (irritability, syncope, seizures, death)
  
  • tx of spell = squatting/knee chest position, O2, morphine, bicarb, pressor, propanolol (if not asthmatic), transfusion if anemic

TX:

• palliative (temporizing)
  
  • systemic to PA shunt (Blaylock Taussig shunt) = enables blood to reach underperfused lung either by directly attaching one of subclavian arteries to PA (classic) or by creating conduit b/n the 2 (modified)
  • decrease RV outflow obstruction (operative or interventiional catheterization to enlarge pulm outflow)
• corrective
  
  • close VSD
  • relieve RV outflow (subpulmonic/pulmonic stenosis)
• ​total repair = VSD patch, enlarging RV outflow tract patch, and take-down of aterial-pulm shunt

DX:

• Echo/Doppler
• MRI or CT

Question 6

Patent ductus arteriosus

Answer 6

epidemiology:

• rare in adults
  
  • usually asx, at least until middle age
• 6% of congenital HD
• premature infants

pathophysiology:

• embryonic ductus arteriosus allows shunting of blood from PA to aorta in utero and normally closes after birth so pulm blood flows only to pulm arteries
• failure to close = shunt connecting L PA and aorta
• kept open before birth thorugh prostaglandins
• persistent L to R shunt in systole and diastole (continuous murmur)
  
  • V overload LA and LV; CHF
  • high pulm flow = pulm vascular disease
• if large enough => pulm HTN (eisenmenger physiology)

S:

• most asx unless pulm HTN develops
• CHF if large

O:

• hyperdynamic double apical impulse
• pulse pressure is wide and diastolic pressure is low
• continuous “rough machinery” murmur, accentuated in late systole at time of S2 heard best at: 1st and 2nd ICS at LSB
• thrills are common
• if pulm HTN is present (Eisenmenger) => shunt reverses and lower body gets desat blood and upper gets sat blood=> hands appear normal and toes are cyanotic and clubbed

DX:

• Echo/Doppler
• CT and MRI are best noninvasive modalities

TX:

• large shunt = mortality from HF
• HF in small shunt but later on
• spontaneous closure <6 mo
• premature infants = indomethacin or PDA ligation
• older pts = embolization and catheterization or PDA ligation
• prostaglandin inhibitors may close it

Complications

• infecive endocarditis or endoarteritis

Question 7

Transposition of the great vessels

Answer 7

epidemiology:
* 5% of congenital HD
anatomy:

• aorta arises from RV
• pulmonary artery arises from LV

pathophysiology:

• cyanotic at birth
• survival requires mixing systemic and pulmonary venous return via PDA, ASD, VSD

TX:

• IV prostaglandin to keep ductus open
• balloon atrial septostomy if needed
• sx repair = switch great vessels and move coronaries