ACHD: ASDs (1)

On examination: murmur which could be pulmonary ejection systolic murmur with fixed splitting of the second heart sound or triscupid regurgitation

ECG findings:

  • RAD
  • LAD (ostium primum)
  • incomplete RBBB
  • RVH
  • conduction disease

Symptoms from ASDs include:

  • mild exercise intolerance
  • DIB
  • palpitations from atrial arrhythmias (afib, flutter) or ectopics

Complications:

  • Pulmonary hypertension (rare in those <20yo but present in 50% of those >40yo)
  • paradoxical embolism / stroke
  • atrial arrhythmias
  • RV failure
  • Eisenmenger’s syndrome (occurs in 5-10%)

No evidence that ASDs increase risk of infective endocarditis

Most secundum ASD are asymptomatic to early adulthood.

70% are symptomatic before 40 years.

ASDs can involve the SVC, IVC or even the coronary sinus.

Investigations:

  • TTE is fine in most case
  • TOE needed if TTE suboptimal, ASD is large (>3cm) or doubt about possible contraindications.
  • Cardiac catheterisation: useful to confirm ASDs, assess shunt fraction, PA pressures and vascular resistance.
    • If the PA pressure is >75% of the systemic pressure, then reversibility studies with PA vasodilators should be performed.
    • Patients >40you usually also require coronary angiography

If you close an ASD in someone <25, they should have the same life expectancy as someone without an ASD

Unclear about asymptomatic 25-40 you with a significant shunt

Closing an ASD in someone with an ASD and cyanosis is often inappropriate due to the high procedural risk, regardless of the method.

ASD closure may cause immediate RV failure as the afterload against the RV suddenly increases.

Indications for percutaneous ASD closure:

  • Secundum ASD <40mm or less with left to right shunt Qp:Qs >1.5
  • Significant right heart volume overload (RA and RV dilatation)
  • Paradoxical embolisation

Contraindications for percutaneous ASD closure:

  • ASD > 40mm (stretched diameter)
  • Insufficient rim (<5mm) – occlusion device could obstruct SVC, IVC, tricsupid or mitral valve
  • Ostium primum, sinus venosus, coronary sinus defect or anomalous pulmonary drainage
  • Other conditions that require cardiac surgery
  • Intracardiac thrombus, sepsis or decompensated CCF
  • Pulmonary hypertension with net right to left shunt and systemic desaturation

Source: Oxford case histories in Cardiology by Rajendram et al

ACHD: Interatrial defects

Here is an image my father drew of interatrial defects



  • There are 4 types of interatrial defects – their name depends on their location: at the top is a sinus venosus defect, middle is secundum ASD (and PFO) and at the bottom is primum ASD
  • A persistent sinus venosus defect should result in RA / RV enlargement due to the left to right shunting
  • A sinus venosus defect involves either the SVC (superior) or IVC (inferior)
  • Superior sinus venosus defects (which are located the junction of the SVC and RA) make up 2-3% of all ASDs and are often associated with anomalous drainage of the right sided pulmonary veins into the RA instead of the LA
  • When people refer to an “ASD” – they’re usually referring to a secundum ASD
  • Primum ASDs are difficult to treat percutaneously especially if there is no “ridge” (which is apparently best visualised on TOE) and therefore are often treated surgically
  • In general, when it comes to interatrial shunting seen on TTE / TOE, if there are no right heart changes, the shunt is probably significant (and certainly not enough to be causing symptoms or oxygen desat)