Congenital Heart Disease Flashcards
What is the most common CHD?
Ventricular septal defect (25-30%)
What are the types of CHD exhibiting a left to right shunt?
VSD, ASD, PDA
How might we classify VSD according to its locations? For each, describe the chance of spontaneous closure.
• Perimembranous:
- bordered directly by fibrous continuity b/n AV + arterial valves
- intermediate chance closure, some risk aortic valve regurgitation
• Muscular:
- completely in muscular septum
- high chance spontaneous closure, can be difficult for surgical closure
• Doubly committed:
- bordered by fibrous continuity between leaflets of aortic and pulmonary valves
- Low chance spontaneous closure, significant risk aortic valve regurgitation
Describe the murmur produced by VSD
- LLS ejection holosystolic (louder with more restrictive i.e. smaller VSD)
- can radiate to RLS
- smaller VSD related to more palpable thrill
When do symptoms usually present for a VSD?
When PVR fallsnormally after birth, usually 1-3 weeks
- May have very little net intracardiac shunt right after birth -> baby no Sx, no murmur
What can develop if a VSD remains untreated?
- Left ventricle dilatation
- Einsenmenger syndrome (now rare): long-standing left-right shunt -> pulmonary HTN -> reversal into cyanotic right-left shunt
What Ix could you do to diagnose a VSD?
- Echo: location and number VSDs, estimation pressure gradient-assess RVP, ?LV dilatation, ?associated defects
- ECG: prominent left and right ventricular forces
- CXR: pulmonary plethora and cardiac enlargement
What are the clinical features of a VSD?
- Cyanosis
- Failure to thrive
- Sweaty, tachypnoiec with feeds
- SOB
- clubbing
- recurrent pulmonary infections
What kind of conservative Mx is available for a VSD?
Similar to actual HF, but without the BBs:
• *Diuretics (frusemide/spironolactone)
○ to reduce pulmonary extravascular water
• Afterload reduction - ACE inhibitor
○ reducing systemic vascular resistance improves oxygen delivery
○ Trying to make the balance between SVR and PVR less - so the net shunt will be lower.
• Balance risk of endocarditis with prophylactic abx - in only some pts now!
When might surgery be indicated for a VSD?
- Failure to respond to meds
- VSD with pulmonic stenosis
- Large VSD with pulmonary HTN
- VSD with aortic regurgitation
What kind of procedural methods are there to repair a VSD?
- Surgery–standard care if closure required
- Closure of defect - perimembranous, doubly committed, many muscular VSDs
- Pulmonary artery band - apical muscular
- Catheter device closure
- Muscular
- Surgical device closure
- Apical and mid muscular
Epidemiology of ASD:
- % of CHD
- When do symptoms arise?
- M/F
- 8% of CHD
- ~3rd-4th decade, very rare early on
- F > M
What is the most common type of ASD?
Secundum defects:
- in region of fossa ovalis while sinus venosus type defects in region SVC or IVC
What kind of murmur is heard in ASD?
- Only heard in greater degrees of left-right shunt
- ejection systolic at ULSB i.e. pulmonary
- fixed splitting of S2 (pathognomonic)
Explain the pathophysiology of the S2 splitting that occurs in ASD, and how this differs then from normal physiological splitting of S2.
- Normal: splitting in insp, none in exp.
- Insp -> neg intra-thoracic P -> inc VR -> RV volume loading -> pul valve delays closure
- Exp -> split no longer heard bc less neg intra-thoracic P
- Fixed splitting in ASD i.e. no variation b/n exp and insp.
- ASD creates left to right shunt that causes pul valve to always close later than the aortic
