ASD Flashcards
Presentation
- Lesions not recognised in childhood tend to present in 3rd and 4th decade
- Dyspnoea (pulmonary HTN or AF)
- Palpitations (atrial rhythm disturbances)
- TIA/Stroke - paradoxical emboli, AF
- right heart failure
- unexplained respiratory tract infections
Signs
- features of associated syndromes eg marfans syndrome (low set ears, flat nasal bridge, prominent epicanthic folds, glossoptosis, simian palmar crease)
- signs of stroke
- pulse could be irregular die I AF
- normal, elevated due to HF or TR due to RV overload
- thrust over RV if overloaded
- On Auscultation:
- S1 normally normal but could be pronounced as TV leaflets opened vigourously by volume overloaded RA then shut vigourously by overloaded and hyperdynamic RV
- soft ejection systolic murmur due to exaggerated flow through normal PV for same reason as above
- PSM 2ry to TR if caused by RV overload
- S2 is fixed and widely split. P2 occurs later due to increased PV flow. Communication between atria prevent the normal variations in pressure between both during respiration
- P2 May be louder due to pulmonary HTN
- rarely soft low-pitch diastolic murmur in large ASD due to increased blood flow over an effectively narrowed TV
- signs of right heart failure
Severity
Large ASD indicated by:
- evidence of RV overload
- pulmonary HTN
- soft low-pithed diastolic murmur
- AF (due to LA enlargement 2ry increased pulmonary venous return)
Less severe
- absence of the above
- soft pulmonary systolic murmur
Types
Primum ASD
- more correctly AV separation defect. Often associated with VSD and other defects. Abnormality in development of endocardial cushions so defect is in ostium premum (related to Down’s syndrome)
Secondum ASD
- defect in fossa ovalis due to incomplete development of septum secondum or excessive resorption of septum primum during development. This does not include patent foramen ovale
Sinus venosus ASD - abnormal folding of septum causing IVC also emptying into LA and also commonly pulmonary veins emptying into RA.
Coronary sinus ASD
- defect in wall between LA and coronary sinus
Investigations
- ECG: AF, abnormal p-waves 1st HB, partial RBBB, LAD in primum, RAD in secendum
- CXR - cardiomegaly, atrial enlargement, pulmonary artery dilatation
- TTE, bubble contrast may be necessary
- TOE to further assess defectsamd suitability for closure. Need to see sinus venosus defect
- R+L cardiac catheterisation. Can be useful for measuring pressures if Echo inconclusive. Can also assess reversibility of pulmonary HTN. If >40 then needed preoperarively anyway
- cardiac MRI - detailed anatomy definition and function and shunt assessment
- lung biopsy if right heart catheter with vasodilator test unclear in reversibility of pulmonary HTN
Management
No intervention required in most.
Offer surgery if:
- paradoxical embolism
- symptomatic
- significant shunt (ratio pulmonary to systemic flow >1.5)
- significant pulmonary HTN (>2/3 systemic) AND shown to have reversibility with right heart catheter dilation and the shunt fraction is at least 1.5
Lutembacher syndrom
Coexistence of secondum ASD and rheumatic MS. Can also be acquired by atrial septal puncture for PBMV to treat rheumatic MS
