Congenital heart diseases
Objectives
§ Epidemiology and aetiological factors of CHD
§ Describe the normal fetal circulation mention the changes that occur after birth
§What are the acyanotic heart diseases
§Presentation / Clinical features and investigations findings of acyanotic Heart diseases
§Treatment options of acyanotic CHD
Epidemiology
§Common - Prevalence: 0.8% of live births (8/1000)
§The incidence is higher in stillborn (3-4%), spontaneous abortions(10-25%), and premature infants (approximately 2%)
§Increased recognition and advances in treatment has improved the mortality rates due to CHD
Aetiology of CHD
§The causes of most congenital heart defects is unknown
§Multifactorial and result from a combination of
§ genetic predisposition
§ environmental stimulus
§ Risk of recurrence of increases if a 1st-degree relative is affected (so ask in history)
Genetic predisposition
CHD are related to chromosomal abnormalities
> Single gene disorders
§Trisomy 21- Downs Syndrome( 50%)
§Trisomy 18- Edward Syndrome(> 90%)
§Trisomy 13- Patau Syndrome
§XO -Turner syndrome. (40%)
Genetic causes - Microdeletions /mutations
§Ellis–van Creveld syndrome (polydactyly, ASD)
§Holt-Oram syndrome (limb defects, ASD
§Alagille syndrome (bile duct hypoplasia, cardiac lesions)
§Cri du Chat syndrome
§DiGeorge syndrome- 22q112 deletion
Maternal conditions and teratogenic influences
§Maternal diabetes mellitus
§Phenylketonuria,
§Systemic lupus erythematosus
§Congenital rubella syndrome
§Ingestion of drugs such as lithium, anticonvulsants
§Foetal alcohol syndrome
Presentations
§Antenatal anomaly scan 18-22 weeks
§Neonatal screening – heart murmur /pulse oximetry
§Detection of heart murmur subsequent visits in asymptomatic pts
§Heart failure (large lesions -> decompensations)
§Shock (hyperplastic leaft heart, critical coarctation)
§Cyanosis (right to left shunt)
§It is only after birth when the fetal pathways begin to close that the full hemodynamic impact is apparent
Fetal Circulation
- Before birth, blood from the placenta, about 80% saturated with oxygen, returns to the fetus by way of the umbilical vein.
- On approaching the liver, most of this blood flows through the ductus venosus directly into the inferior vena cava, bypassing the liver.
- In the inferior vena cava, where placental blood mixes with deoxygenated blood returning from the lower limbs, it enters the right atrium.
- guided toward the oval foramen by the valve of the inferior vena cava, and most of the blood passes directly into the left atrium.
- From the left atrium, where it mixes with a small amount of desaturated blood returning from the lungs, blood enters the left ventricle and ascending aorta.
- Since the coronary and carotid arteries are the first branches of the ascending aorta, the heart musculature and the brain are supplied with well-oxygenated blood.(62%)
- A small amount of blood from the IVC is prevented from entering the left atrium and remains in the right atrium.
- It mixes with desaturated blood returning from the head and arms by way of the superior vena cava.
- Desaturated blood from the superior vena cava flows by way of the right ventricle into the pulmonary trunk.
- During fetal life, resistance in the pulmonary vessels is high, such that most of this blood passes directly through the ductus arteriosus into the descending aorta, where it mixes with blood from the proximal aorta.
- After coursing through the descending aorta, blood flows toward the placenta by way of the two umbilical arteries.
- The oxygen saturation in the umbilical arteries is approximately 52%.
Circulatory changes at birth
- Changes in the vascular system at birth are caused by cessation of placental blood flow and the beginning of respiration.
Closure of the umbilical arteries
§It is accomplished by contraction of the smooth musculature in their walls.
§Functionally the arteries close a few minutes after birth, although the actual obliteration of the lumen by fibrous proliferation may take 2 to 3 months.
§Distal parts of the umbilical arteries form the medial umbilical ligaments and the proximal portions remain open as the superior vesical arteries.
Closure of the umbilical vein and ductus venosus
§It occurs shortly after that of the umbilical arteries.
§After obliteration, the umbilical vein forms the ligamentum teres hepatis in the lower margin of the falciform ligament.
§The ductus venosus is also obliterated and forms the ligamentum venosum.
Closure of the ductus arteriosus
- It is caused by contraction of its muscular wall which occurs almost immediately within 1-3 days after birth.
- Complete anatomical obliteration by proliferation of the intima is thought to take 1 to 3 months.
- In the adult, the obliterated ductus arteriosus forms the ligamentum arteriosum.
Closure of the oval foramen
- Since the ductus arteriosus closes by muscular contraction of its wall, and decrease in pulmonary resistance the amount of blood flowing through the lung vessels increases rapidly. This, in turn, raises pressure in the left atrium.
- Simultaneously, pressure in the right atrium decreases as a result of interruption of placental blood flow.
- The septum primum is then apposed to the septum secundum and functionally the oval foramen closes.
- Constant apposition gradually leads to fusion of the two septa in about 1 year
CLASSIFICATION OF CHD
ACYANOTIC CHD
§Left to right Shunts
- Atrial septal defect (ASD)
- Ventricular septal defect (VSD) - most commonest
- Patent ductus arteriosus (PDA)
§Stenotic Lesions
- Pulmonary stenosis (PS)
- Aortic stenosis (AS)
- Coarctation of the aorta (CoA)
VSD
Types
ü membranous /
perimembranous ~75% - 2
ü muscular ( single or multiple) - 4
ü Inlet (subaortic) - less common
ü Infundibular (subpulmonary ) - less common
Symptoms relate to the
§Size
§degree of shunt
§pulmonary vascular resistance
>> if small: < 3mm - no symptoms - detection of a murmur on newborn examination or later routine examination
pink
normal pulses
normal P2 (no pulmonary hypertension)
± systolic thrill
harsh pansystolic murmur LLSE
§ECG: may be normal (no strain)
>>Larger defect:
§ murmur is not very loud
§ may have complication such as PH (loud P2)
§ may have mitral flow murmur (MDM @ apex )
§ may present /develop heart failure:
§dyspnoea
§slow feeding
§head sweating
§failure to thrive
§tachycardia, cardiomegaly
§gallop rhythm and basal crepts
hepatomegaly (important in infancy )
In large VSD ……
§CXR- increased pulmonary vascularity + cardiomegaly
ECG - RVH ± LVH
Complications
Complications of VSD
§Failure to Thrive
§Recurrent chest infections
§Pulmonary hypertention
§Herat failure
§Infective Endocarditis
§Aortic Valve proplapse
§ Eisenmenger Syndrome
Treatment Options
§Conservative (spontoneous closure in 90 % within 1st year )
§Monitor for Qp/Qs ratio serial echcardigraphy to check any development of pulmonary hypertension
§ Device closure via catheter or Surgical closure before pulmonary vascular changes become irreversible (= eisenmenger's syndrome following reversal of shunt)
§Maintain good dental hygiene
§Endocarditis prophylaxis
§Treatment of heart failure captopril, +- digoxin,diuretics.
Atrial septal defect
Types
Formation of atrial septum
Secundum ASD
§Usually no symptoms in childhood
§pink, normal pulses, soft ESM @ ULSE
§wide & ‘fixed’ split S2
§Pulmonary valve closes late P2 is delayed -WIDELY SPLIT S2
§RV is fully loaded so further increase RV volume in inspiration does not occur FIXED SPLIT S2
§CXR: often normal /sometimes pulmonary plethora
§Complications
§Pulmonary hypertension
§Infective endocarditis - very rare
§Arrythmia- in later life
§Haemodynamic significance of ASD is assessed to decide if closure appropriate
§Usually get closed spontaneously age 3-5 years (mostly < 8mm)
§If large /persists Two options for closure:
- interventional catheter – device closure
- surgery - suture or patch
Patent Ductus Arteriosus (PDA)
§Often asymptomatic
§CHF symptoms if large ductus in very young infant or preterm babies
§Examination :
§Pink
§collapsing pulse/bounding pulse
§continuous ‘machinery’ murmur loudest under left clavicle
§ECG: normal (small PDA) or LVH ±
§CXR: Normal or if large ± cardiomegaly, pulm plethora
§Options for closure:
interventional catheter
surgery - ligation–
preterm babies medical closure with indomethacin/paracetamol
Pulmonary Stenosis
§Usually asymptomatic
§
§pink , normal pulses, ESM loudest @ ULSE
± systolic ejection click
§CXR: normal ± prominent MPA (post-stenotic dilatation)
§ECG: RAD, RVH
§Treatment of valvar PS
§Mild pressure gradient – No intervention
§
§Moderate/Severe
balloon valvuloplasty preferred
uncommonly surgical valvotomy
Aortic Stenosis
§often asymptomatic;
ü cardiac syncope (exercise induced syncome think cardiac syncope!)
ü chest pain on exertion
§Examination
- pink
- small volume pulse, slow rising pulse
- ± LV lift (coz of high pressure)
- ± systolic thrill (suprasternal, URSE)
- ± systolic ejection click
- harsh ESM loudest @ URSE & radiating to carotids
S2 (even reversed)
§ECG: normal (mild AS) LVH ± strain(more severe AS)
§CXR: often normal ± LVH
§Treatment
§Mild- No intervention . Follow up
§AS (moderate/severe):
- balloon valvuloplasty
- surgical valvotomy
Coarctation of the Aorta
§Neonate if severe CoA – heart failure and collapse
§In older children often asymptomatic , hypertention or incidental finding of a murmur
§Examination:
§Pink
§ reduced or absent femoral pulses (screening in neonatal examination )
§ soft systolic murmur mid LSE, and/or mid interscapular region
Neonatal pulse oximetry screening for CCHD
right hand and lower limb
§To detect critical congenital heart defect (CCHD)
§Some examples of critical CHDs include coarctation of the aorta, transposition of the great arteries, hypoplastic left heart syndrome
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CHD FIRST TUTORIAL = where the recording?
And need to research certain parts!!!!!!!1
True/False type MCQ
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7) Developmental milestones of a 2 year old child is as followsHe can stand with support but not walk. Able to reach and grasp objects but does not transfer. No pincer grasp . He cannot hold a cup and feed. He gets upset with the approach of strangersWhich is the most appropriate development age of this child
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9) An eight year old child is seen in the paediatric outpatient clinic as he has had a syncope while taking part in his practices for the sport meet relays. On examination he had a heart rate of 80/minute with no radio-femoral delay. An ejection systolic murmur was heard in the upper sternal edge on right side. The most likely cause for the syncope is
SEQ
1) You are the paediatric house officer on duty to the postnatal ward. During the neonatal examination of a newborn baby you notice that the baby has up slanting eyes and a simian creases in the palms. He was also noted to have a pan systolic murmur in the lower left sternal edge
a) What is most likely cardiac abnormality (10 marks)
b) List 5 complications of the above condition (30 marks)
c) What is the prognosis of the condition mentioned above (30 marks)
d) List 5 features of heart failure in infancy (30 marks)
2) Write short notes on
a) Physiological basis of fixed split in ASD ( 25 marks)
b) Neonatal pulse oximetry screening (25 marks)
c) Aeitiology of CHD (25 marks)
d) Diagnosis of Coractation of aorta ( 25 marks)
CYANOTIC HEART DISEASE
AND REST OF CHD LECTURES???????????????