Cardiology: Acyanotic CHD Flashcards
What examples are there?
ASD
VSD
PDA
Describe the shunt
Left to right
What does the left to right shunt cause?
Pulmonary HTN
R heart hypertrophy
What do the symptoms depend on?
Extent of the malformation
How do infants present?
Exercise intolerance
Failure to thrive
Symptoms of HF
Recurrent bronchopulmonary infections
What common complications can occur?
IE
Arrhythmias
Embolisms
(Especially is treatment delayed)
What is Eisenmenger syndrome?
Prolonged pulmonary HTN due to a L to R shunt causes constriction and permanent remodelling of pulmonary vessels, leading to irreversible pulmonary HTN
RV hypertrophies to compensate and eventually RV pressure higher than LV pressure and shunt reversal occurs. This provokes the onset of cyanosis (deoxygenated blood enters systemic circulation)
What causes of ASD are there?
Down syndrome
Fetal alcohol syndrome
Holt-Oram syndrome
What types of ASD are there?
Ostium secundum ASD (80%)
Ostium primum ASD
Both similar symptoms but anatomy different:
- secundum = defect in centre of atrial septum involving foramen ovale
- primum = communication between bottom of atrial septum and AV valves, abnormal AV valves, left AV valve has 3 leaflets and leaks
Ostium primum defects are also called…
Endocardial cushion defects
What symptoms can occur with ASDs?
Usually asymptomatic Recurrent chest infections Wheeze Palpitations due to arrhythmias HF symptoms
What heart murmur is associated with ASD?
Systolic ejection murmur over upper left sternal edge (due to increased flow over pulmonary valve due to L to R shunt)
Describe the second heart sound heard in ASD?
Fixed and widely split - due to RV stroke volume being equal in both inspiration and expiration
Delayed pulmonary valve closure
What will CXR show in ASD?
Cardiomegaly
Enlarged pulmonary arteries
Increased pulmonary vascular markings
What ECG findings are associated with ASD?
Secundum: partial RBBB common, RAD, p pulomonale, PR prolongation
What investigation is definitive?
ECHO
How are ASDs managed?
In childhood spontaneous closure may occur
In those with significant ASD large enough to cause RV dilation require treatment
Secundum: cardiac catheterisation with insertion of occlusion device
Primum: surgical correction required
At what age does treatment usually occur with ASD?
3 to 5 years
To prevent right HF and arrhythmias later in life
What does the ductus arteriosus connect?
Descending aorta and pulmonary artery
In term infants, when does the DA close?
Shortly after birth
In PDA it has failed to close by…
1 month after the expected date of delivery
Following the fall of pulmonary vascular resistance after birth, blood flows which way across the PDA?
Left to right
What causes PDA?
Premature infants
Maternal rubella infection during pregnancy
Maternal prostaglandin administration
Trisomies - Down, Patau, Edwards
What can the resulting L to R shunt cause in PDA?
Volume overload of pulmonary vessels
What type of murmur is associated with PDA?
Continuous murmur beneath left clavicle
What symptoms are associated with PDA?
May be asymptomatic
Failure to thrive
HF symptoms
What can signs are associated with PDA?
Wide pulse pressure - causing a collapsing or bounding pulse
Heaving, laterally displaced apical impulse
What confirmatory test can be done for PDA?
ECHO
Doppler to assess degree of shunt and pulmonary artery pressure
What are the indications for PDA closure?
Symptomatic
Pulmonary HTN
Cardiomegaly
How is PDA closed?
In preterm: infusion of indomethacin or ibuprofen
In infants > 5kg precutaneous catheter occlusion or surgical ligation
What should be given if the PDA is needed for survival?
Prostaglandin
Why is PDA closure recommended?
Reduce bacterial endocarditis risk and pulmonary vascular disease
Describe how the atrial septum develops
Septum primum growns downward - and leaves a gap called the ostium primum
The septum primum then continues to grow and meets the endocardial cushion
A hole appears in the upper septum called the ostium secundum
The septum secundum growns down, covering ostium secundum and leaves a small opening called the foramen ovale
= makeshift valve
At birth, the septum secundum and septum primum slap shunt and fuse to close off the foramen ovale
Are VSDs common?
Yes they account for 30% of all cases CHD
Where is the defect in VSDs?
The defect can be anywhere in the ventricular septum, perimembranous (adjacent to the tricuspid valve) or muscular (completely surrounded by muscle)
What symptoms are associated with small VSDs?
Usually asymptomatic
What symptoms are associated with large VSDs?
HF with breathless
Faltering growth
Recurrent chest infections
