An Atrial septal defect is a congenital heart defect that causes a shunting of blood from the left to the right atria.
L-to-R shunt – ACYANOTIC
There are two types of Atrial Septal Defect:
- Secundum ASD
- 80% of ASD’s
- Basically, a patent foramen ovale
- Partial AVSD
- Minority of cases
- Usually involves a defect around the bottom of the atrial septum, and typically involves the tricuspid valve
- Clinical features of both types are very similar
- In both instances, blood will flow from left to right through the defect
Clinical features
- Commonly asymptomatic
- Recurrent chest infections / wheeze
- Heart failure
- Arrythmias – not until >4th decade of life
Examination
- Split second heart sound
- Ejection systolic murmur – best heard at the left sterna edge – due to increase bloodflow in the right ventricular outflow tract
Investigations
- Secundum
- RBBB (but this is common in many children anyway)
- Right axis deviation
- Partial AVSD
- Left axis deviation
- Superior QRS axis – the AVSD is typically in the region of the AV node, thus conduction is altered, and conduction occurs to the ventricles ‘superiorly’
Management
Secundum ASD
- Usually cardiac catheterisation. A device can be inserted to close off the defect
Partial AVSD
- Surgery usually required
- Usually performed at age 3-5 to prevent prevent RHF and arrhythmias in later life
References
- Murtagh’s General Practice. 6th Ed. (2015) John Murtagh, Jill Rosenblatt
- Oxford Handbook of General Practice. 3rd Ed. (2010) Simon, C., Everitt, H., van Drop, F.
- Beers, MH., Porter RS., Jones, TV., Kaplan JL., Berkwits, M. The Merck Manual of Diagnosis and Therapy