Ventricular septal defect/atrial septal defect

Question 1

ASD - background

Answer 1

1. May be subtyped as ostium secundum or partial atrioventricular septal defect (ostium primum)

Question 2

ASD - ostium secundum defect (overview)

Answer 2

1. Defect in region of foramen ovale; AV valves are normal. Defect is usually isolated, found incidentally and 3x more common in girls
2. Clinical features = most children asymptomatic; may rarely result in HF
3. Ix (3) = ECG (often shows RBBB - ?), CXR (may show cardiomegaly with pulmonary plethora), **echocardiography (to confirm dx)
4. Prognosis = defects usually well-tolerated; symptoms and complications usually only present in the 3rd decade or later
5. ASD closure is required and advised for all pts, even if asymptomatic. Usually achieved by insertion of an occlusion device at cardiac catheterisation or by open heart surgery (can do direct suture or patch closure if unsuitable for transcatheter approach). Intervention should be performed in early childhood, before school entry

Question 3

ASD - partial AVSD (background)

Answer 3

1. More serious ASD. Affects endocardial cushion tissue that gives rise to mitral and tricuspid valves. Located in lower atrial septum and associated with a three leaflet mitral valve (normally bicuspid). These abnormalities result in a left to right shunt with valve incompetence. AVSD are often seen in Down syndrome
2. Clinical features (3) = most children with small defects are asymptomatic; those with larger defects are predisposed to recurrent chest infections + HF
3. Ix = ECG (LAD + RBBB - ?; presence of LAD distinguishes primum ASDs from secundum defects), CXR (usually shows marked cardiomegaly and pulmonary plethora), **echo (dx)
4. Prognosis = depends on degree of L to R shunt, pulmonary HTN and severity of mitral regurgitation; without surgical repair, congestive cardiac failure may develop in infancy/early childhood
5. Mx = definitive tx with surgical closure of the defect. Placement of patch to close ASD and repair of mitral valve

Question 4

Complete AVSD - overview

Answer 4

1. Significant VSD coexisting with primum ASD (ASD that abuts on AV valves)
2. Sx = presentation resembles that of VSD; difficulty feeding and failure to thrive
3. Ix = ECG, CXR, echocardiography

Mx

4. Surgical repair almost always required. If PHTN present, generally recommend surgery in early months of life (3-4mo). Tx HF and FTT (adequate nutrition)
5. Operation = patch repair with prosthetic patch material, repair of AV valve

Question 5

VSD - background

Answer 5

1. Account for 25% of all congenital heart disease (2:1000 live births)
2. May occur in isolation or as part of complex malformations
3. Clinical features depend on size and location of the defect

Question 6

VSD - clinical features

Answer 6

1. Asymptomatic - typical/early
2. Heart failure (breathlessness - after the first few days of life); recurrent chest infections
3. Failure to thrive; trouble feeding
4. Rare after first decade of life - secondary to Eisenmenger syndrome (any untx L to R shunt converted into R to L shunt due to elevated pulmonary arterial pressures and associated pulmonary vascular disease)
5. Endocarditis (late)

Question 7

VSD - examination findings

Answer 7

1. Pansystolic murmur - lower left sternal edge
2. Parasternal thrill
3. Tachypnoea, increased work of breathing
4. Large VSD - displaced apex
5. Hepatomegaly (frequently seen - ?)

Question 8

VSD - ix (3)

Answer 8

1. ECG (frequently normal with small defects, often shows biventricular hypertrophy with larger defects)
2. CXR (frequently normal with small defects; shows cardiomegaly and increased pulmonary plethora with larger defects)
3. Echocardiography (*dx, site and size of defect)

Question 9

VSD - prognosis and management

Answer 9

1. Majority of small defects will close spontaneously
2. Tx heart failure (medically) if present

Surgery

3. Indicated if severe HF; pulmonary hypertension
4. Performed at 3mo of age, before the pulmonary HTN causes pulmonary vascular disease (Eisenmenger syndrome)
5. Methods of closure = open heart surgery or transcatheter techniques if suitable