Congenital Heart Disease Flashcards
what are the 2 extra connections in a fetal heart that close after birth
- patent foramen ovale: passage between atria, R to L shunt from high O2 right side to left side
- ductus arteriosus: connects pulmonary artery to aorta, shunting blood away from the pulmonary bed to the body
Why do the PFO and DA eventually close after birth
because L sided pressure is higher than R sided after breathing and systemic vascular resistance increases
What is the time frame in which the PFO and the DA close
PFO: within 6 months (due to the loss of R sided pressure)
DA: within 2-3 days (due to L-R pressure change & ecrease in prostaglandins from mom)
Describe some risk factors for CHD
- prematurity
- family history
- genetic syndromes
- maternal factors (DM, HTN, obesity, thyroid, connective tissue, epilepsy, substances)
- fertility (assisted reproductive therapy)
- in utero infection (CMV, rubella, etc)
When is a standard OB ultrasound done with cardiac windows
18-22 weeks
- evaluates outflow tract and 4 chambers
- not all lesions identifiable
- does not evaluate rhythm or function yet
- can proceed to fetal echo if higher risk of CHD
Describe cyanotic CHD
lesions that allow circulation of deoxygenated blood into systemic circulation via intracardiac or extracardiac shunting
Describe ductal-dependent CHD
dependent upon a patent ductus arteriosus to supply pulmonary or systemic blood floow or to allow adequate mixing between parallel circulations
Describe critical CHD
refers to lesions requiring surgery or catheter based interventions in the 1st year of life
List some acyanotic CHD
- atrial septal defect
- ventricular septal defect
- patent ductus arteriosus
- coarctation of the aorta
List some cyanotic CHD
- truncus arteriosus
- HLHS
- tetralogy of fallot
- total anomalous pulmonary venous return
- transposition of great vessels
Describe some physical manifestations of hypoperfusion
- cold extremities
- cyanotic
- poor cap refill
- tachy
- metabolic acidosis
What is ECMO
extracorporeal mechanical oxygenation
- pulmonary bipass
- does job of the lungs
- kids waiting for emergent CHD repair can sit on ECMO for days
Describe cardiogenic shock
circulatory failure
- tissue hypoxia d/t reduced oxygen delivery and/or increased oxygen consumption or inadequate utilization
Can kids with VSD, ASD, and PDA participate in sports?
Yes, with rare exceptions, as long as hemodynamically insignificant
What is the average O2 sat in utero
60%
Which CHDs are ductal dependent
coarctation of the aorta and transposition of the great vessels
Describe the etiology of atrial septal defect
Septation between atria fails to close resulting in a L to R shunt
Pathophys depends on location, compliance of ventricles, & size of defect
Oxygenated blood going back into lungs & venous circulation
Describe the etiology of patent foramen ovale
Transient shunting between R and L atria during times of high R sided pressure (coughing, valsalva, straining)
Normal shunting in fetus but doesn’t spontaneously close as it should
Describe the etiology of ventricular septal defect
Common, Communication between ventricles (single or multi), shunting L to R
Location class
- peri/membranous
- muscular defects
- outlet defects (subpulmonic)
- inlet defects (AV canal)
Describe the etiology of patent ductus arteriosus
Fetal vascular connection between main pulmonary artery & aorta that diverts blood away from pulm bed - fails to completely close postnatally
Results in some oxygenated blood leaving LV and going back to lungs, L to R
Describe the etiology of coarctation of the aorta
Narrowing of descending aorta usually at ductus arteriosus, often assoc with other CHDs
Cardiac output must cross narrow segment to reach lower extremities after birth
Cardiac output increases over time d/t resistance/outflow tract obstruction resulting in LV overload
Describe the etiology of truncus arteriosus
Blood vessels from heart fail to separate in development (typically see VSD too), resulting in a connection between the aorta and pulmonary artery and mixing of systemic & pulmonary blood flow
Describe the etiology of HLHS
Diminutive LV and small L side structures incapable of supporting systemic circulation so RV supports
Survival depends on PDA to maintain systemic circulation and ASD to allow adequate mixing of oxygenated and deoxygenated blood
Describe the etiology of tetralogy of fallot
10% of all CHD, most common cyanotic CHD
During development the septum deviates:
1. VSD
2. Overriding aortic root
3. R ventricular outflow tract obstruction
4. RV hypertrophy
