ASD
Presentation
Sir, this patient has atrial septal defect as evidenced by presence of a wide and fixed
splitting of the second heart sound.
There is presence of an ejection systolic murmur over the pulmonary area which is louder
on inspiration, implying presence of a pulmonary systolic murmur. This is a grade 3/6
murmur and there is no associated systolic thrill.
There is no associated mid-diastolic flow murmur to suggest relative tricuspid stenosis or
Lutembacher’s syndrome (Acquired MS and ASD). There was also no associated PSM to
suggest an ostium primum defect (TR, MR, VSD).
The apex beat is not displaced and is located in the 5th IC space just medial to the midclavicular line.
There is no complication of Eisenmenger’s syndrome; there is no evidence of pulmonary
hypertension; is not clubbed and no central cyanosis. There is also no evidence of
congestive cardiac failure.
There are no stigmata of infective endocarditis. Patient is in atrial fibrillation with an
irregularly irregular pulse and is rate controlled at a rate of 84 bpm; there are also no
bruises to suggest over-anticoagulation.
There is no evidence of any thumb defects to suggest Holt-Oram syndrome. The patient
also does not features of Down’s syndrome.
I would like to complete my examination by examining patient’s chest for pneumonia as
patients are prone to recurrent chest infections as well as a neurological examination to
look for evidence of stroke due to paradoxical embolus.
In summary, this patient has got an ASD with complications of AF. There are no
complications of pulmonary hypertension, heart failure or Eisenmenger’s syndrome.
There is also no infective endocarditis. This patient has ASD is most likely due to an
ostium secundum atrial septal defect which is a congenital heart condition.
Questions
What are the types of ASDs?
o Ostium secundum type
o 90%
o common congenital heart condition
o Most remain asymptomatic
o If small <2 cm, normal life expectancy with no symptoms
o Larger defects may present in the second or third decades with dyspnea or
fatigue
o defect in the fossa ovalis with no involvement of the AV valves
o Ostium primum type
o 10%
o Failure of fusion of the septum primum with the endocardial cushions
o AV valves affected – MR, TR and VSD
o Sinus venosus type
o Defect in the septum just below the entrance of the SVC (inverted P waves
in the inferior leads)
How do patients present?
o Secundum
o Asymptomtic
o Symptomatic
 Fatigue, dyspnea
 Right heart failure
 AF
 Recurrent pulmonary infections
 Paradoxical emboli
o Primum
o In addition to the above
 Failure to thrive, poor development
 IE
 Syncope (heart block)
What are the complications of ASD?
o Pulmonary hypertension, heart failure, Eisenmenger’s
o AF, IE (primum defects)
o Recurrent chest infection, paradoxical emboli
What are the various types of murmurs that can be associated with ASD and what do they
mean?
o Pulmonary ejection systolic murmur and mid-diastolic murmur at the triscuspid
area implies increased flow of blood through the pulmonary and triscupid valve
respectively due to left to right shunting of blood via the ASD
o MS murmur means acquired Rh heart disease affecting the mitral valve in
Lutembacher’s syndrome
o MR, TR or VSD murmur implies that ASD is of the ostium primum type
What is the mechanism of a split second heart sound?
o A split S2 is caused physiologically during inspiration because the increase in
venous return overloads the right ventricle and delays the closure of the
pulmonary valve
Why is there wide and fixed splitting of the second heart sound in ASD?
o With an atrial septal defect, the right ventricle can be thought of as continuously
overloaded because of the left to right shunt, producing a widely split S2, with the
pulmonary valve closing much later cf to the aortic valve
o It is fixed because the atria are linked via the defect, inspiration produces no net
pressure change between them, and has no effect on the splitting of S2
How do you differentiate between a flow mumur through the pulmonary valve vs a PS
murmur?
o PS murmur is a/w P2 that is soft, delayed and varies with respiration
What are the conditions that can cause a wide splitting of the second heart sound?
o Increase RV volume – ASD, VSD, PR
o Increase RV pressure – PS
o RV conduction delay –RBBB
o Increase LV emptying – MR, VSD
What is Eisenmenger’s syndrome?
o It implies a reversal of a left to right shunt as a result of the development of
pulmonary hypertension
o This occurs in conditions such as ASD, VSD or PDA
o Patients are markedly clubbed and deeply cyanosed
o The defect must not be repaired once this complication occur due to high
mortality risk
What is Lutembacher’s syndrome?
o Acquired Rh MS
o ASD
What is Fallot’s trilogy?
o ASD
o RVH
o PS
What is Holt-Oram syndrome?
o ASD secundum type
o Hypoplastic thumb with accessory phalanx
o Autosomal dominant
How would you investigate?
o ECG
o Secundum – Partial RBBB, RAD
o Primum – LBBB, LAD, low atrial rhythm
o Sinus venosus – inverted P in inferior leads
o Pulmonary hypertension – p pulmonale, RVH
o CXR
o Cardiomegaly
o Pulmonary hypertension
 Prominent pulmonary trunk
 Enlarged RA and RV
o Shunt vascularity/pulmonary plethora (well visualised pulmonary arteries
in the periphery of the lung
o Small aortic knob
o Echocardiogram
o Diagnosis - demonstrate the defect
o Cardiac catheterisation
o Determine the severity and direction of shunt
How would you manage?
o Counsel
o Medical
o No antibiotic prophylaxis required, repaired or unrepaired
o Treatment of complications such as heart failure and AF
o May consider anticoagulation if there is evidence of bidirectional shunting
to prevent strokes from paradoxical emboli
o Surgery
o Early childhood – closure is recommended at 5-10 years of age to prevent
complications
o Small ASDs can be left alone(5 mm or less)
o Large ASDs or pulmonary to systemic flow ratio>1.5
o Closed surgically or transcatheter button or clam-shell devices
o Closure prevents pulmonary hypertension and RHF but does not alter
incidence of AF
How would you counsel a patient with ASD who intends to get pregnant?
o Pregnancy is well tolerated in patients with small and hemodynamically
insignificant ASD
o For large defects with pulmonary hypertension, Eisenmenger’s syndrome, avoid
pregnancy as there is increase morbidity and mortality both to fetus and mother
o Routine closure before pregnancy as complications of progressive pulmonary
vascular disease may develop