congenital heart defects Flashcards
(116 cards)
ASD prevalence
1.6/1000 live births
females more common
how atrial septum formed
two separate endocardial cushions during 4th week of gestation. Septum primum grows from the roof of the atrium down towards the atrioventricular endocardial cushions, closing off the ostium primum. The ostrium secondum grows downwards to septum primum and the space between the septum primum and secondum is foramen ovale
patent foramen ovale
Foramen ovale closes after birth when vascular resistance changes…BP increases and pulmonary pressure decreases causing a decrease in right atrium pressure..if not remains open
5 types of ASD (COMMON -> LEAST)
Patent foramen ovale
Ostium secundum defect
Ostium primum defect
Sinus venosus defect
Coronary sinus defect
Ostium secundum defect
incomplete occlusion of ostium secundum by septum secundum or too much reabsoprtion of septum primum from atrium roof
ostium primum defect
septum primum fails to fuse with endocardial cushions, allowing blood to travel from left to right atrium
- can be complete (spans from atrium to ventricles) or partial (just ostium primum)
sinus venous defect
superior defect - When superior vena cava (SVC) opening runs on top of oval fossa (foramen ovale remnant) of atrial septum. This renders SVC draining blood from both LA and RA. Usually co-exists with abnormal communication between SVC and right superior pulmonary vein
inferior defect - Less common than superior defect, but occurs when IVC orifice overrides LA & RA. Can co-exist with abnormal communication between IVC and right inferior pulmonary vein
coronary sinus defect
an absence in the roof of the coronary sinus. This can be partial or focal, allowing transmission between coronary sinus and left atrium.
risk factors ASD
aut dom, treacher-collins syndrome, TAR syndrome - ostium secondum ASD
family history
Maternal smoking in 1st trimester
Maternal diabetes
Maternal rubella
Maternal drug use e.g. cocaine & alcohol
ASD prognosis
not by itself life threatening, but co-existing increases mortality, same life expectancy unless diagnosis missed
post surgery - high risk of atrial flutter and AF
sx of large ASD in paeds
Tachypnoea
Poor weight gain
Recurrent chest infections
examination ASD
Murmur: soft, systolic ejection murmur, best heard over pulmonary valve region (2nd ICS, figure 2).
Wide, fixed split S2
Diastolic rumble in lower left sternal edge in patients with large ASD
investigations ASD
ECG - usually normal unless large defect…tall p waves, right BBB, right axis deviation
transthoracic echo is gold standard
cardiac MRI - measure pulmonary v systemic blood flow ratio (Qp/Qs)
CXR - cardiomegaly
initial management ASD
ASD < 5mm, spontaneous closure should occur within 12 months of birth.
In adults, if patient is presenting with no signs of right heart failure and a small defect, then monitor every 2 – 3 years with echocardiogram3.
If presenting with arrhythmia, control rhythm with drugs & anticoagulated before definitive surgical treatment
if child has HF - diuretics
definitive management ASD
surgical closure if ASD >1CM
via percutaneously (transcatheter) or open chest20 (central stenotomy) using cardiopulmonary bypass. Surgical closure is not recommended in patients where pulmonary hypertension is present (mean pulmonary pressure of 30mmHg), as this can induce RV failure if the ASD is closed up.
Percutaneous closure is carried out in cath lab and chosen method dependent on age of child
complications of percutaneous closure
Arrhythmias
Atrioventricular block
Thromboembolism (VTE aspirin)
indications for surgical closure
TIA / stroke
Ostium primum defects
Sinus venous defects
Coronary sinus defects
consequences of untreated large ASD
arryhtmias
pulmonary HTN
Eisenmenger syndrome (presenting with: chronic cyanosis, exertional dyspnoea, syncope, increased risk of infections, increased pulmonary vascular resistance)15
Cyanosis (only if Eisenmenger)
Peripheral oedema (if eventually leading to heart failure)
TIA / stroke
ASVD association
Down’s syndrome
Heretotaxy syndromes
ASVD pathophysiology
Primitive AV canal connects atria and ventricles. At 4-5 weeks of gestation, superior and inferior endocardial cushions of common AV canal fuse and contribute to formation of AV valves and septum…if endocardial cushions do not fuse correctly…causes apical displacement of AV valve and incomplete formation of ventricular septum
if complete failure of superior and inferior endocardial cushiosn to fuse = ASD nad VSD and single common atrio ventricular valve forms
if partialfailure - partial AV canal defect with ASD, a common valvular annulus with 2 separate AV valve orifices and cleft in anterior mitral leaflet
complete AVSD
increased shunting of blood from left to right at both atrial and ventricular levels..excessive pulmonary blood flow…HF and increased pulmonary vascular resistance. Also atrioventricular valve regurg
partial AVSD
left to right shunting at level of atrial septal defect…volume overload of both right atrium and ventricle…not enough to majorly affect pulmonary artery pressures…no sx until adulthood
regurg from LV to RA through defect…R sided volume overload
investigations AVSD
increased distance between aorta and apex of heart - ‘goose neck deformity’ on echo
karyotyping - down’s
ECG - superior QRS axis, prolonged PR, RVH in V1
cxr - cardiomegaly
clinical features AVSD
Tachypnoea
Tachycardia
Poor feeding
Sweating
Failure to thrive