Acyanotic congenital heart disease Flashcards
List the L-R shunts
Atrial Septal defects
Ventricular Septal defects
Patent Ductus Arteriosus
Endocardial cushion defects
Partial anomalous pulmonary venous drainage
What happens in L-R shunts
Characterized by hyper-oxygenated blood which keeps re-circulating through the lungs –at expense of systemic circulation.
The lungs become over-perfused because they receive:
all the deoxygenated blood from the systemic venous return
PLUS blood shunted from the left side
Volume overload of one or more cardiac chambers
Increased cardiac workload to supply rest of body with enough blood to meet metabolic demands
What is the relation of pulmonary to systemic blood flow and how does this affect the severity of L-R shunts
this is 1:1 because equal volume of blood is pumped to body and lungs
In L-R shunts, this ratio is >1
Qp:Qs ratio <1.5:1 = small shunt;
1.5-2.0:1 = moderate,
while >2:1 is a large shunt
Describe the levels of L-R shunting
Venous level: anomalous drainage of pulmonary veins( total, partial) – into RA and /or its tributaries
Atrial level: atrial septal defects / single atrium
Ventricular level: ventricular septal defects / single ventricle
Arterial level: PDA, arteriovenous malformations
What are the types of ASD
Ostium secundum
Ostium primum
Sinus venosus
Coronary sinus
What causes ostium secundum defects
Excessive fenestration or resorption of septum primum
Under development of septum secundum
Or combination of both
The magnitude of ASD depends on what factors
Size of the defect
Relative compliance of the right and left ventricles
Vascular resistance in the pulmonary and systemic circulations
Clinical features of ASD
Asymptomatic
Mild FTT in younger children
Varying degrees of excercise intolerance seen in older children
What investigations would you carry out for ASD and what will be the findings
CHEST XRAY
Normal heart size in small defects
In large defects:
Cardiomegaly
Enlarged RA and RV
Increased pulmonary vascular markings
ECG
Right axis deviation
Right ventricular hypertrophy
ECHO
Location and size of defect
Right atrial and right ventricular enlargement
Describe the natural history of ASD
Most children with ASD remain asymptomatic
The defect may decrease in size with up ato 33% closing spontaneously usually before age 30 months, especially if small
Spontaneous closure is rare after age 4 years
Symptoms such as pulmonary hypertension, congestive heart failure and complications such as atrial arrthymias usually develops in adults especially with large ASDs.
What is the most common cardiac malformation
VSD accounting for 25% of all CHD
What are the types of VSD
Perimembranous
Muscular (or Trabecular)
Inlet (or Posterior / AVcanal-type / endocardial cushion–type)
Outlet (or Subarterial /supracristal / infundibular, subpulmonic )
Describe the pathophysiology of VSD
When both ventricles simultaneous contract, blood shunts from the left to the right side of the heart.
The shunted blood DOES NOT remain in RV but immediately enters the main pulmonary artery which dilates.
There is increased pulmonary blood flow and increased pulmonary venous return to LA
There is dilation of the LA and LV followed by LVH
The increased pulmonary venous return leads to an increase in the pulmonary arterial, arteriolar and capillary pressure leading to increased pulmonary interstitial fluid
When severe, pulmonary edema results
Prolonged exposure of pulmonary vascular bed to higher than normal blood flow at high pressure results in Pulmonary vasoconstriction in an attempt to protect the lungs
This increases pulmonary vascular resistance(PVR) and subsequently causes pulmonary hypertension(PHT)
The PHT is initially reversible but ultimately irreversible changes occur in the smooth muscle which lead to pulmonary vascular disease
Describe eisenmenger physiology
If this pulmonary vascular resistance continues, the ratio of pulmonary to systemic resistance approaches 1.
Then, the shunt is no longer Left –to- right but becomes bidirectional
The patient becomes cyanotic———- Eisenmenger physiology
Clinical presentation of VSD
Small Defects
Mild or no symptoms
Most often brought to the cardiologist’s attention because of a murmur (pan-systolic murmur heard best at the lower left sternal border± thrill) detectedduring routine examination.
Feeding or weight gain usually not affected.
Moderate to large defects
Delayed growth and development
Decreased exercise intolerance- feeding difficulties
Repeated pulmonary infections due to pulmonary congestion.
Excessive sweating due to increased sympathetic tone
Congestive cardiac failure
Cyanosis in older children with long standing pulmonary hypertension
What are the physical findings of VSD
Pan-systolic murmur LLSB
Precordium is hyperactive with signs of congestive cardiac failure- tachypnea, tachycardia, enlarged liver(if VSD is large)
P2 is normal or slightly accentuated if there is associated pulmonary hypertension
What investigations would you carry out for VSD and what will be the findings
Chest Xray
Normal heart size or minimal cardiomegaly : Small VSD
Gross cardiomegaly with increased pulmonary vascular markings: Large VSD
ECG
Normal/left ventricular hypertrophy: small VSD
Biventricular hypertrophy: Large VSD
ECHO
Position and size of the defect
CARDIAC CATHETERIZATION
Increased oxygen content and pressure in the right ventricle in large defects
Describe the natural history of VSD
Ranges from spontaneous closure to congestive heart failure (CHF) to death in early infancy
30-50% of small defects close spontaneously. Spontaneous closure is frequent before the age of 2 years, uncommon after age 4 years
Most frequently observed in muscular defects (80%), then perimembranous (35-40%)
Most children with small defects remain asymptomatic but have a high risk of infective endocarditis
Large defects may get smaller but it is less common for them to close spontaneously.
These patients have repeated chest infections and heart failure despite optimal medical management
Pulmonary vascular obstructive disease can develop in patients with large defects as early as 6 -12 months of age.
How would you treat VSD
Control of Congestive cardiac failure
Prompt treatment of chest infections
Palliation if definitive treatment is not immediately feasible e.g., PA banding for large VSD
Prevention of infective endocarditis
Management of complications (if present)
Surgery
PDA is associated with which syndrome
Congenital rubella syndrome
What featured differenciate PDA from VSD
Bounding peripheral pulses
continuous murmur at the infraclavicular area
What is the treatment of PDA in preterms
If small and asymptomatic, monitor for 6 months because of the possibility of spontaneous closure
If symptomatic, medical or surgical intervention:
Fluid restriction to 120mls/kg/day
Diuretic- Furosemide 1mg/kg/dose 8-12hourly for 24-48 hours
IV Indomethacin 0.2mg/kg/dose 12 hourly for up to 3 doses ( a second course may be necessary to achieve closure in some cases) CI: Low platelet count(<80,000/mm3), bleeding tendencies, NEC, hyperbilirubinaemia, high BUN (>25mg/dl), high creatinine (>1.8mg/dl)
IV Ibuprofen 10mg/kg stat, followed 24 hours later by 5mg/kg daily x 2 doses from the 3rd day of life
Surgical ligation of the ductus when medical treatment is unsuccessful or contraindiacted
Describe coarctation of the aorta
The discrete constriction/ stenosis of the upper thoracic aorta or a long segment
Rarely abdominal aorta is involved
Male dominance M:F = 2: 1
It could be familial, among patients with Turner’s syndrome
Other associated cardiac defects: abnormal aortic and mitral valve, VSD, aortic hypoplasia
What are the types of coarctation of the aorta
Preductal
Juxtaductal
The usual site
Postductal
What are the clinical features of CoA
NEONATAL
Feeding difficulties
Respiratory distress
Signs of shock-oliguria, severe acidaemia
Sweating
GENERAL
Radiofemoral delay
BP differential in 4 point BP determination
Single loud S2
POST NEONATAL
Upper limb hypertension
Headaches
LV failure
Tachycardia, tachypnoea
Tender hepatomegaly etc
Lower limb hypotension
Calf pain
Intermittent claudication
Poor pulses
What investigations would you carry out to diagnose CoA and what will be your findings
CXR
Cardiomegaly and pulmonary congestion in severe cases
3 sign
Enlarged ascending aorta
Indentation of the COA
Post stenotic dilatation
Rib notching
ECHO
Identify segment of coarctation
Cardiac catheterization & Aortic angiography
To identify collateral blood flow and other anomalies
How would you treat CoA
MEDICAL
Treat CCF, shock, acidosis
Infuse prostaglandin E1 to keep the ductus patent
Catheter intervention
Balloon dilatation and stents
SURGICAL
Resection and end-to-end anastomosis
Patch aortoplasty
