Congenital Heart Disease I & II

Question 1

Physiologic abnormalities w/patent ductus arteriosis

Answer 1

• Prenatally the blood goes from pulmonary artery to aorta (due to high PVR).
• At birth the PVR drops and blood flows from the aorta to the pulmonary artery.
• The pulmonary circulation, LA and LV become volume overloaded –> LV dilatation and L-HF.
• Right side is normal unless pulmonary vascular disease ensues, and if it does pt can get Eisenmenger syndrome where the blood goes from pulmonary artery to descending aorta

Question 2

Clinical & hemodynamic features of atrial septal defects

Answer 2

• Hemodynamics: Shunt lets blood through according to resistance. Usually Left to right (LA pressure > RA pressure)
• Clinical Features:
  
  • rarely presents in infancy
  • Sweating with feeds, increased RR
  • liver 2-3 cm below R costal margin.
  • 2-3/6 systolic ejection murmur at upper left sternal border ± diastolic rumble at lower left sternal border (<–NOT CAUSED BY BLOOD FLOW ACROSS DEFECT)
    
    • systolic=increased flow across pulmonic
    • diastolic=increased flow accross tricuspid
  • S2 widely split.

Question 3

Dx approaches and clinical hx of ASD

Answer 3

• Diagnostic approaches:
  
  • CXR: possible enlarged heart, enlarged pulmonary artery, prominent pulmonary vascular marking
  • Echo –> size/location of defect
  • ECG: Right axis deviation, RVH
• Natural history: often undetected in childhood, long term risk of pulmonary vascular disease, atrial arrhythmias, cardiac failure (RHF)

Question 4

Hemodynamics features of Ventricular Septal defects

Answer 4

• Can have large shunts that let pressure equalize between R & L
• Usually a L to R shunt (pulmonary vascular resist < systemic VR)
• Preferential flow to the lungs results in large LA
• Increases EDV.
  
  • Frank Starling kicks in = higher contractility, increased LV output.

Question 5

Dx approach/tx & natural history of VSD

Answer 5

• Diagnostic approaches: Characteristic exam, echo = definititive
  
  • ECG: right axis deviation, RVH/LVH possible
• Treat with diuretics or close the hole.
• Natural history: Most close on own, large ones decrease in size, large defects not treated can be devastating

Question 6

Hemodynamics & Clinical features of Tetralogy of Fallot

Answer 6

• Hemodynamics: Moved muscle that leaves a hole and has moved to underneath the pulmonary valve.
• Clinical features:
  1. ​​​​right ventricular outflow obstruction.
  2. RVH
  3. VSD
  4. Dextraposition of the aorta (aorta overrides VSD)
  5. **Blue baby w/loud murmur
• Most common cyanotic defect

Question 7

Dx & Natural course features of Tetralogy of Fallot

Answer 7

• Natural history: If RVOT is severe and patient has dependant ductal flow- they will die when ductus closes w/o intervention.
  
  • Otherwise, they can survive into young adulthood- clubbing, bleeding, limited exercise tolerance, arrhythmias, cerebral abscesses.
  • Kids may squat during exercise to increase SVR and PBF. Squatting reduces shunting R → L by increasing systemic vascular resistance. Also, increases venous return to the heart.

Question 8

Hemodynamics of coarctation of the aorta

Answer 8

• Narrowing of the aortic lumen.
• Localized shelf in the wall of the aorta- usually in the area of the ductus
• Aorta can dilate before and after the shelf
• obstruction –> poor descending aorta perfusion
  
  • decreased blood flow to bowel, leg muscles, kidneys

Question 9

Clinical features of coarctation of aorta

Answer 9

• occurs in 15% of Turner syndrome pts
• decreased blood flow –> Necrotizing enterocolitis, claudication, increased RAAS activation, rebound hypertension after repair
• Asymptomatic until ductus closes, after it closes, tachypnea, diaphoresis (sweating), poor feeding, cardiac failure/shock
• in infancy–> FEMORAL PULSES LACKING!
• In childhood: hypertension, lower extremity claudication, headaches.
• PE: tachycardic, blood pressure differential b/w upper and lower ext, rales, hepatomegaly, S2 and S3 gallop, systolic click over apex

Question 10

Dx approaches & natural course of coarctation of the aorta

Answer 10

• Diagnostic approaches:
  
  • PE: tachycardic, BP differential btwn upper and lower extremities, pulmonary rales or hepatomegaly, possible extra heart sounds/murmurs
    
    • Absent or weak femoral pulses
  • ECG- Right axis, RVH
  • Echo
  • CXR: aortic knob, coarctation, post stenotic dilation
• ​Natural history: Development of collateral arteries to supply blood flow to tissue and organs below the obstruction. Look for BP differential.

Question 11

Clinical features (history & PE) of VSD

Answer 11

• respiratory distress
• diaphoresis w/ feeding
• failure to thrive
• Physical exam (large VSD):
• Active precordium
• loud S2
• 2-3/6 harsh holosystolic murmure at lower left sternal border, diastolic murmur
• Murmur IS CAUSED by flow across the defect.

Question 12

Clinical features of Tetraology of Fallot

Answer 12

• Clinical Features: Blue babies if R → L shunt. If blood can get through pulmonary artery, shunt will be L → R and baby will be pink.
• Murmur is caused by the PA obstruction (narrow) not the VSD.
• Can have a tet spell precipitated by prolonged crying, anemia, dehydration
• Tachycardic and cyanotic if blue tet.
• Diaphoretic and tachypneic if pink tet.
• Precordial impulse relocated to lower left sternal border = RV dominance.

Question 13

“Shunt definition”

Answer 13

• connection between 2 chambers or vessels
• shunt direction determined by pressure/resistance differences
• “L to R”: from systemic chamber into pulmonary chamber
• “Systemic chambers”: pulmonary veins, LA, LV, aorta
• “Pulmonary chambers”: systemic veins, RA, RV, pulmonary artery

Question 14

Clinical Hx presentation of PDA

Answer 14

• smaller PDAs often asymptomatic
• Larger PDAs in neonates:
  
  • respiratory effects: pulmonary edema/congestion
  • CHF
  • feeding inteolerance
  • renal insufficiency
  • intraventricular hemoorhage or stroke
  • death
• Older children: hoarse cry, pneumonias/respiratory difficulties, failture to thrive

Question 15

Physical exam findings w/PDA

Answer 15

• wide pulse pressure –> bounding pulses
• increased work of breathing
• hyperactive precordium
• variable murmurs:
  
  • classic = continuous/machinaery sounding murmur @ LUSB
  • systolic ejection possible
• Loud P2 if pulmonary HTN

Question 16

Dx of PDA

Answer 16

• Hx + physical exam
• CXR: large PDA –> increased pulmonary vascular markings, enlarged LA/LV
• confirm w/echo

Question 17

Tx of PDA

Answer 17

• asymptomatic neotate: conservative management
• symptomatic neonate: COX inhibitors or surgical ligation
• symptomatic older child: percutaneous occlusion

Question 18

Risk factors for developing PDA

Answer 18

• mother w/Rubella
• born @ high altitude
• prematurity

Question 19

Natural history of PDA

Answer 19

• large PDA –> pulmonary veno-occlusive disease/”Eisenmenger syndrome” = irreversible pulmonary hypertension
• increased risk of bacterial endocarditis

Question 20

Characteristics of Eisenmenger Syndrome

Answer 20

Question 21

Physiology of Tetralogy of Fallot

Answer 21

• large VSD –> equalization of LV & RV pressures
  
  • much of circulating blood bypasses pulmonary circulation (hence cyanosis)
• sources of pulmonary blood flow:
  
  • RV –> pulmonary aa.
  • Ductus arterious flow <– primary source of flow if outflow obstruction is severe
    
    • maintain PATENT DA w/PROSTAGLANDINS
• shunt direction depends on resistance to flow
  
  • R –> L: RV outflow resist > SVR = cyanosis
  • L –> R: RV outflow resist < SVR = no cyanosis

Question 22

Dx/PE features of Tetralogy of Fallot

Answer 22

• Blue tet = tachycardic and cyanotic
  
  • “squatting” –> increases SVR
  • clubbing
  • JVD
• Pink tet = diaphoretic and tachypneic
• Precordial impulse displaced to LLSB (b/c RV dominance)
• 2-3/6 short systolic murmur (pulmonary stenosis)
• ECG has right axis deviation and RVH