Congenital Heart Disease 2 Flashcards
congestive heart failure - overview & causes in adults vs. infants
*defined as state where the heart is unable to pump blood/oxygen at rate needed by the body’s demands
*several mechanisms:
-weak heart (most adult pts)
-strong but inefficient heart (infants with congenital heart disease, esp shunt lesions)
CHF - compensatory changes
*hypovolemia detected by the body leads to:
-renal salt & water retention
-increased catecholamine levels
-cardiac remodeling
causes of CHF in pediatrics - by age group
*neonates: obstructive lesions (coarctation, aortic stenosis)
*infants: shunt lesions (VSD, PDA)
*older children/adolescents: cardiomyopathy
CHF physical exam in pediatrics
*vital signs - HR, RR, BP
*respiratory status (usually tachypneic)
*distal perfusion (cap refill, temperature)
*pulses (often diminished, but could be bounding)
*hepatomegaly
*extracardiac malformations
atrioventricular septal defect - aka
*endocardial cushion defect
*AV canal
atrioventricular septal defect - consists of
- ostium primum ASD
- VSD
- common AV valve
atrioventricular septal defect (AVSD) - physiology
*behaves like a large VSD:
-left to right shunt
-congestive heart failure (poor feeding/poor weight gain, pulmonary edema & respiratory distress, diaphoresis)
*treatment involves surgical repair at 4-6 months of age
atrioventricular septal defect & trisomy 21
*40-50% of AVSD patients will have trisomy 21
*45% of children with trisomy 21 have a heart defect
*at least 25% of trisomy 21 patients have an AVSD
hypoplasia - defined
*developed, but smaller than normal
atresia - defined
*never formed at all
*valve atresia = door never opened; a solid shelf exists instead of a functional valve
stenosis - defined
*only opens partially
*obstructed
acyanotic congenital heart defects - obstructive lesions
*pulmonic stenosis (PS)
*aortic stenosis (AS)
*coarctation of the aorta
pulmonic/aortic stenosis - murmur
*murmur due to turbulent blood flow through narrowed valve orifice
*higher pressure gradient, higher pitch
*thrill = vibration felt over the skin, indicating severe turbulence
pulmonic/aortic stenosis - clinical findings
*mild to moderate pulmonic/aortic stenosis: asymptomatic
*some findings include:
-shift in PMI
-RVH on EKG
*severe pulmonary stenosis = CYANOSIS
*sever aortic stenosis = SHOCK (cardiogenic)
pulmonic/aortic stenosis - physiology
*higher ventricular pressures need to overcome valve stenosis
pulmonic/aortic stenosis - treatment
*neonate: prostaglandins (to maintain PDA as a second source) until surgery
*no treatment needed for mild to moderate aortic or pulmonic stenosis
*if severe stenosis or sick infant:
-valvuloplasty (catheter placement with balloon to expand the valve)
peripheral pulmonic stenosis (PPS)
*physiologic turbulence at the bifurcation of the pulmonary trunk into the L and R pulmonary arteries
*normal in infants < 6-9 months
*grade 1-3 (out of 6) systolic ejection murmur heard over back/axillae
*usually not heard in immediate newborn period
coarctation of the aorta - overview
*narrowing of the aorta, usually near the insertion of the ductus arteriosus
coarctation of the aorta - 2 common presentations
*neonatal: CHF & cardiogenic shock
*infancy/childhood: heart murmur, systemic HTN, decreased lower extremity pulses
*four-extremity blood pressure is a good way to identify (upper blood pressures will be high and lower will be low)
coarctation of the aorta - epidemiology
*etiology unknown
*7% of congenital heart diseases
*male predominance
*associated with bicuspid aortic valve, other left sided lesions, and VSD
*associated with TURNER SYNDROME (monosomy X)
coarctation of the aorta - neonatal clinical presentation
*progressively worsening feeding
*pallor
*diaphoresis
*tachypnea
*lethargy
*grunting
note - essentially they present in heart failure
coarctation of the aorta - older child clinical presentation
*usually asymptomatic
*leg discomfort?
*headaches
*epistaxis
coarctation of the aorta - treatments
*neonatal: prostaglandins (maintain the open ductus arteriosus)
*surgical intervention is the definitive therapy
*older children: stenting of the hypoplastic aorta
prostaglandins - overview
*prostaglandin E1
*alprostadil
note - prostaglandins are used to maintain the ductus arteriosus in certain conditions in neonates, as keeping it open allows for a secondary pathway of blood flow
uses of prostaglandin treatment
*cyanotic (blue) babies with no respiratory distress:
-transpositions
-tricuspid or pulmonary atresia
*acyanotic but shocky (gray) kids with poor distal pulses (especially femoral pulse) & perfusion:
-HLHS
-critical aortic stenosis
-coarctation
*prenatally-diagnosed single ventricle patients
prostaglandins - ADEs
*vasodilator (systemic & pulmonary) → hypotension, flushing
*apnea
*fever
*seizures
cyanosis - defined
*a physical exam finding
*bluish coloration of the skin/mucous membranes due to presence of deoxygenated hemoglobin in the circulation
*visible when the equivalent of 3-5 gm/dL of Hb has no oxygen in it
acrocyanosis
*“blue edges” = hands & feet
*NORMAL finding in newborns, or environmental reaction in children
*not the same implication as true cyanosis
*sluggish circulation in the periphery allows for extensive removal of oxygen by the tissues → blue tint
causes of cyanosis
*respiratory problems: not breathing/sick lungs
*cardiac problems: due to deoxygenated blood going directly to the body due to cardiac defects (RIGHT to LEFT shunt)
cyanotic congenital heart disease - examples
*cyanotic CHD is caused by RIGHT TO LEFT SHUNTS
*the Terrible T’s:
1. truncus arteriosus
2. transposition of the great arteries
3. tricuspid atresia
4. Tetralogy of Fallot
5. total anomalous pulmonary venous return (TAPVR)
6. also, pulmonary atresia & critical pulmonary stenosis
Tetralogy of Fallot (TOF) - overview & elements of diagnosis
*caused by anterosuperior displacement of the infundibular/conal septum
*most common cause of early childhood cyanosis
*characterized by:
1. OVERRIDING AORTA (straddles VSD, receiving blood from both LV and RV)
2. VSD
3. RVOT obstruction (pulmonary infundibular stenosis)
4. right ventricular hypertrophy
Tetralogy of Fallot (TOF) - clinical presentation
*fetal diagnosis
*CYANOSIS
*murmur (from pulmonary stenosis, not from VSD)
*boot-shaped heart on CXR
*EKG with right ventricular hypertrophy or right axis deviation
Tetralogy of Fallot (TOF) - Tet Spell
*sudden increase in RVOT obstruction (infundibular stenosis) OR sudden drop in systemic venous return → pulmonary stenosis forces right-to-left flow across VSD
*s/s:
-TERROR (agitation, fear, “possessed”, not just a little fussy or cranky)
*INTENSE CYANOSIS
*hyperpnea
*diaphoresis
Tetralogy of Fallot (TOF) - Tet Spell: precipitating events
*crying
*defecation
*feeding
*awakening from naps
*fevers
*dehydration
*tachycardia (decreased filling time leads to reduced end-diastolic volume)
*medications (ACE inhibitors, sedation)
Tetralogy of Fallot (TOF) - Tet Spell: treatment
1st: calm yourself & the infant; knee to chest position; oxygen
2nd:
-fluid bolus
-morphine
-ketamine
-phenylephrine
-beta blockers
-surgical shunt
Tetralogy of Fallot (TOF) - treatment
*repair may be staged (modified BTT shunt) or complete
D-transposition of the great arteries (D-TGA) - overview
*aorta leaves RV (anterior) & pulmonary trunk leaves LV (posterior) → separation of systemic and pulmonary circulations
*due to failure of the aorticopulmonary septum to spiral
*not compatible with life unless a shunt is present to allow mixing of blood
*survival dependent upon mixing at atrial, ventricular, or great vessel level (via ASD, VSD, or PDA)
D-transposition of the great arteries (D-TGA) - clinical findings
*findings depend on level of mixing:
-often profound cyanosis
-large infants (due to associated with maternal diabetes)
-no respiratory distress
-maybe tachypnea from acidosis/hypoxia
-no murmur
-loud S2
D-transposition of the great arteries (D-TGA) - CXR finding
*egg on a string CXR (narrow superior mediastinum)
D-transposition of the great arteries (D-TGA) - treatment
*balloon atrial septostomy (temporary)
*switch the connections so that LV connects to aorta & RV connects to pulmonary artery
