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
