congenital heart defects Flashcards
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
examination avsd
characteristics of down’s
signs of congestive HF - hepatomegaly, gallop rhythm, oedema,crackles
pallor or harrisons grooves (chronic tachypnoea)
hyperactive precordium
systolic heave along left sternal border
palpable apical thrill
auscultation complete AVSD
An accentuated S1
Loud pulmonary component of S2 – In complete AVSD, the second heart sound narrowly splits and P2 increases in intensity (due to elevated pulmonary artery pressure)
Ejection-systolic murmur: best auscultated along Left upper sternal border (pulmonary area) due to increased blood flow through a normal pulmonary valve.
Mid-diastolic murmur: best auscultated along Left lower sternal border and apex due to the increased flow across the common atrioventricular valve.
Holosystolic murmur: best auscultated along Left lower sternal border and at cardiac apex if left atrioventricular valve regurgitation is present.
partial AVSD auscultation
Wide and fixed splitting of S2: the character of S2 does not change with inspiration
Ejection systolic murmur: best auscultated at Left upper sternal border due to turbulent blood flow across the pulmonary valve – may radiate to the lung fields.
Mid-diastolic murmur: best auscultated at Left lower sternal border. Usually low pitched and represents significant left AV valve regurgitation.
Holosystolic murmur: may be heard at the apex due to regurgitation through anterior mitral cleft
AVSD management
sx relief of HF - diuretics, ACEi, digoxin, adequate caloric intake
complete -> corrective surgery, around 3-6 mths of age
down’s - pulmonary parenchyma hypoplasia…earlier surgery
palliative surgery - pulmonary artery banding..reduce diameter and bloody flow
corrective surgery
via median sternotomy under cardiopulmonary bypass:
Closure of inter atrial communication
Closure of inter ventricular communication
Construction of two separate and competent AV valves from available leaflet tissue
via single, double or modified single patch repair
ASVD complications untreated
Failure to thrive
Recurrent lower respiratory tract infections
Congestive heart failure
Pulmonary Vascular disease
Eisenmenger’s syndrome
ASVD surgical repair complications
Left AV valve regurgitation – this may persist or worsen due to inadequate surgical reconstruction
A residual shunt across ASD or VSD which may require a further repair.
Cardiac conduction defects – Arrhythmias may occur in 10-15% of patients [6]
Sinus node dysfunction resulting in bradycardia
Wound infection due to poor healing
prognosis AVSD
mortality rate 2.5%
reoperation due to worsening mitral rerg
lifelong cardiac follow up
hypoplastic left heart syndrome prevalence
1 in 5000 live births
risk factors hypoplastic left heart syndrome
environmental factors
seasonal variations
in utero maternal infections - rubella, herpes virus, coxsackie, cytomegalovrius
left side of heart to work must have a…
a) Patent ductus arteriosus to ensure adequate systemic circulation and
b) A non-restrictive atrial septal defect to ensure adequate mixing of oxygenated and deoxygenated blood.
the right ventricle in HLHS
has to support both systemic and pulmonary circulations
when become symptomatic HLHS
birth - patent ductus arteriosis is unrestrictive and high pulmonary vascular resistance..adequate systemic perfusion across duct into descending aorta
but PDA closes and pulmonary vascular resistance reduces…decreased systemic perfusion and increased pulmonary flow…cardiogenic shock
spectrum of defects of HLHS
Aortic atresia with mitral atresia (most extreme)
Aortic atresia with patent mitral valve
Aortic stenosis with patent mitral valve
common cardiac associations of HLHS
coronary cameral fistulas
persistent left SVC
anomalous pulmonary venous drainage
medical conditions associated HLHS
CHARGE syndrome
Turner’s
triosomies
microencephaly
clinical features HLHS
initially - healthy
then hypoxaemia, acidosis and shock..unless restrictive patent foramen ovale or intact atrial septum since birth…cardiogenic shock
clinical signs HLHS
Tachycardia, dyspnea and evidence of pulmonary oedema
Weak peripheral pulses, and vasoconstricted extremities
Loud single S2 (due to aortic atresia)
Hepatomegaly (secondary to congestive heart failure)
investigations HLHS
ECG: shows RVH (and occasionally right axis deviation)
CXR: shows pulmonary venous congestion or pulmonary edema. Moderately enlarged cardiac shadow.
ECHO: Diminutive left ventricle, Dilated and enlarged right ventricle, Aortic hypoplasia, Color flow Doppler shows retrograde blood flow in aorta
initial stablisation HLHS
secure patency of duct:
Prostaglandin E2 infusion
Diuretics and inotropic support – in case of congestive cardiac failure
Intubation and ventilation – occasionally required for hemodynamic stabilization
Balloon atrial septostomy – may be required in cases of restrictive IAS
definitive stabilisation HLHS
conversion of the single ventricle into a systemic ventricle and establishing an obstructed pulmonary blood flow by bypassing the heart.
The definitive repair of HLHS is a 3-staged repair:
Stage 1: Norwood procedure
Stage 2: Glenn procedure (Bi-directional Glenn or Hemi-Fontan)
Stage 3: Fontan Procedure
norwood procedure
Atrial septectomy to establish unobstructed pulmonary venous return
Reconstruction of the aortic arch using the main pulmonary artery to establish a systemic circulation
Placement of a modified BT shunt /RV-PA conduit (Sano shunt) to re-establish pulmonary blood flow
Creating a connection between smaller ascending aorta and pulmonary root to establish coronary blood supply (DKS – Dammus-Kaye Stansel)