Left to Right shunts Flashcards
What are the two types of atrial septal defects?
1) Secundum ASD - 80% - there is a defect in the centre of the atrial septum involving the foramen ovale.
2) Partial atrioventricular septal defect (AVSD)/Primum ASD - Defect of atrioventricular septum, involves inter-atrial communication between the bottom end of the atrial septum and AV valves. Characterised by abnormal regurgitant AV valves.
Clinical presentation of atrial septal defect (L to R shunt)?
1) Usually asymptomatic
2) Arrhythmia from 4th decade onwards
3) Recurrent chest infections
4) Ejection systolic murmur best heard at upper left sternal edge - due to increased blood flow through pulmonary valve (L to R shunt)
5) Fixed and widely split heart sound
6) In partial AVSD - apical pan-systolic murmur heard due to AV valve regurgitation
Diagnosis of atrial septal defect?
1) CXR - shows cardiomegaly, enlarged pulmonary arteries, increased pulmonary vascular markings
2) ECG - SASD - RBBB, right axis deviation due to enlargement of RV/
- AVSD - superior QRS axis - problem with AV node conduction to ventricles - abnormal axis
3) ECHO - GOLD STANDARD!!!!!!!!!!!
Treatment of ASD?
Secundum ASD - cardiac catheterisation with insertion of occlusive device
Partial AVSD - Open surgical conduction in order to prevent right heart failure (ankle oedema, sacral oedema, ascites) and arrhythmias in later life
Ventricular Septal defect types?
1) Small VSD’s (80%)
2) Large VSD’s (20%)
VSD’s common - 30% of all congenital heart cases.
Small VSD’s presentation and diagnosis?
1) Smaller than diameter of aortic valve (<3mm).
2) Usually asymptomatic
3) Found pan-systolic murmur at lower left sternal edge
4) CXR and ECG will appear normal - echo needed to diagnose
Treatment of Small VSD’s?
1) These usually spontaneously resolve, and lesion will close - showed by disappearance of murmur and normal ECG
2) Whilst VSD is present - important to prevent bacterial endocarditis through good oral hygeine.
Presentation of Large VSD’s?
(Defined as being same size or larger than diameter of aortic valve (>3mm)
1) Heart failure with breathlessness and failure to thrive (faltering growth after 1 week old)
2) Recurrent chest infections
3) Tachypnoea, and tachycardia
4) Enlarged liver (due to blood back flow)
Diagnosis of Large VSD?
1) CXR - heart failure picture with cardiomegaly, enlarged pulmonary arteries, increased pulmonary vascular markings, pulmonary oedema.
2) ECG - Biventricular hypertrophy by 2 months, upright T waves (pulmonary hypertension)
3) ECHO - gold standard!!!!!!!!!!
Treatment of VSD?
1) Diuretics - Furosemide
2) ACE-i - Captopril
3) Corrective surgery performed at 3-6 months (always pulmonary hypertension in L to R shunts (and large VSD) - leading to Elsenmenger syndrome if untreated (surgery to prevent)
Pathophys of Patent Ductus Arteriosus?
- Ductus arteriosus connects the pulmonary artery to the descending aorta.
- In term infants it usually spontaneously closes 1-2 days after birth.
- PDA is defined as a ductus arteriosus that has failed to close by 1 month of the expected date of delivery due to a defect in the constrictor mechanism of the duct.
- The flow of blood from the PDA is from the aorta to the pulmonary artery (L to R shunt) following the fall in pulmonary vascular resistance after birth.
- PDA is only abnormal, and the consequence of congenital heart disease in a term infant. In a pre-term infant a PDA is a direct result of prematurity.
Clinical presentation of PDA?
1) Rare to have symptoms
2) Constant ‘machinery’ murmur below the left clavicle.
3) Collapsing or bounding pulse
Diagnosis of PDA?
1) CXR and ECG are normal
2) ECHO DIAGNOSTIC
Treatment of PDA?
1) Ensure duct dependant heart disease is excluded before treatment!!!!
2) Pharmacological give to preterm infants as prophylaxis: NSAID (IV Indometacin (once daily for 3 days)
3) Surgical at 1 year: Cardiac catheterisation involving closing duct with coil or occlusion device, surgical ligation required in large ducts, surgery necessary to prevent the lifelong risk of bacterial endocarditis and of pulmonary vascular disease.
