Paeds Cardio Flashcards
Name the Right to left shunts (blue/cyanotic) in congenital cardiac disease?
Tetralogy of Fallot
Transposition of great arteries
Name the Left to Right Shunts (breathless) in congenital cardiac disease?
Atrial septal defect
Ventricular Septal Defects
Persistent arterial duct
Name the Common mixing (breathless and blue) in congenital cardiac disease?
Atrioventricular septal defects
What are the symptoms of HF in children?
Breathlessness (particularly on feeding and exertion)
Sweating
Poor feeding
Recurrent chest infections
What are the signs of HF in children?
Poor weight gain of faltering growth Tachypnea Tachycardia Heart murmur Enlarged heart Hepatomegaly Cool peripheries
What cardiac changes that occur during birth?
In the fetus the left atrial pressure is low, as relatively little blood returns from the lungs.
The pressure in the right atrium is higher than in the left, as it receives all the systemic venous return including blood from the placenta
The flap valve fo the foramen ovale is held open, blood flows across the atrial septum into the left atrium and then into the left ventricle which pumps blood to the upper body.
With the first breaths resistance to pulmonary blood flow falls and the volume of blood flowing through the lungs increased 6 fold.
Causes a rise in left atrial pressure
Volume returning to right atrium falls as placenta is excluded from circulation.
The change is a pressure difference causes the flap valve of the foramen ovale to be closed.
The ductus arteriosus which connects the pulmonary artery to the aorta in foetal life will normally close within the first few hours to days.
Some babies who rely on blood flow through the duct (duct dependent circulation)
Give some common causes of congenital disorders
Maternal disorders:
Rubella
SLE
SM
Maternal Drugs :
Warfarin
Foetal alcohol syndrome (ASD, VSD, TOF)
Chromosomal T21 (downs) Atrioventricular septal defect and VSD
Where do you hear a ventricular septal defect?
Pansystolic murmur in lower left sternal border
Where do you hear coarctation of the aorta?
Crescendo-decrescendo murmur in the upper left sternal border
Where do you hear a patent ductus arteriosus?
Diastolic machinery murmur in the upper left sternal border
Where do you hear pulmonary stenosis?
Ejection systolic murmur in the upper left sternal border
RFs for tetralogy of fallot?
Males
Tetragons: Alcohol, Warfarin, Trimethadione
Genetics: Charge syndrome & Digeorge syndrome
What are the 4 features of ToF?
A large VSD
Overriding aorta with respect to the ventricular septum
Subpulmonary stenosis causes right ventricular outflow tract obstruction
Right ventricular hypertrophy as a result
What is the pathology behind the 4 features of ToF?
Ventricular septal defect:
Causes systolic pressure between the ventricles to equalise
Pulmonary stenosis
Commonest site = infundibular septum
Results in impaired flow of deoxygenated blood into the main pulmonary artery
May be severe enough to cause intermittent right ventricular outflow tract obstruction - this forms the basis of the hypoxic episodes, commonly known as tet spells
Right Ventricular hypertrophy
Occurs in response to the high pressure → to overcome it
Can be seen as ‘the boot sign’ in chest x rays
Overriding aorta
Dilated and displaces over the interventricular septum
Aortic dilatation is caused by an increase in blood flow through the aorta as it receives blood from both ventricles vias the VSD.
What are the severities of ToF?
Mild (Pink TOF):
These infants have mild PS/RVH and are usually asymptomatic
However the disease normally progresses as the child and the heart grows
Ny 1-13 they will develop severe cyanosis.
Moderate - Severe (Cyanotic TOF):
Infants born with moderate -severe PS may present within the first few weeks with cyanosis and respiratory distress
Develop recurrent chest infections and fail to thrive
Extreme:
TOF with pulmonary atresia and absent pulmonary valve
These are true ‘duct dependent lesions’ as the only way deoxygenated blood can flow into the lungs is through the patent ductus arteriosus (PDA)
Will present within few hours of life if not detected antenatally
What are tet spells?
Peak age of incidence is usually between 2-4 months of life
Paroxysm of hyperpnea:
a) Rapid deep respirations secondary
b) Due to increased right-to-left shunting, carbon dioxide accumulates therefore stimulating the central respiratory centre
c) Self perpetuating (causes more right to left shunting)
Irritability - manifested by prolonged unsettled crying
Increased cyanosis
May be precipitated by dehydration, anaemia or prolonged crying (induces tachycardia and reduced systemic vascular resistance)
What would you hear on auscultation of ToF?
Loud, single S2: due to closure of aortic valve in diastole with absent/reduced pulmonary valve closure (P2) depending on the degree of stenosis.
Loud harsh ejection systolic: best auscultated either mid or upper left sternal edge (LSE). The smaller the VSD the louder the murmur and vice versa.
Ejection click: high pitch noise which occurs at the maximal opening of semilunar (aortic or pulmonary) valves. Clicks in TOF occur due to presence of dilated aorta. Normally heart immediately after S1.
Continuous, machinery murmur: occurs in the presence of PDA with extreme forms of TOF, especially those on prostaglandin infusion. Best auscultated at the upper LSE or left infraclavicular area.
What is the management of ToF?
Medical
Squatting
a) Increases venous return therefore increases systemic resistance
b) Put child in this position whilst waiting for medical review
Prostaglandin infusion
a) This maintains patent ductus arteriosus (in severe TOF)
Beta Blockers propranolol is commonly used in both ‘tet’ spells and prophylaxis in moderate severe disease
a) Peripheral vasoconstrictor and by relieving sub pulmonary muscular obstruction
Surgical
Surgery at 6 months to close VSD, relieve pulmonary tract obstruction
What are the complications of ToF?
Polycythaemia Cerebral abscess Stroke Infective endocarditis Congestive cardiac failure
What is the hallmark of transposition of the great arteries?
Ventriculoarterial discordance
What is the presentation of TGA?
Cyanosis
a) Appears in first 24 hours (if no mixing at the atrial level)
Mild cyanosis - particularly when crying
Signs of congestive heart failure: Tachypnea, Tachycardia, Diaphoresis, Failure to gain weight
From Examination: Prominent right ventricular heave Single second heart sound, loud A2 Systolic murmur potentially if VSD present No signs of respiratory distress
How would you investigate TGA?
Pulse oximetry
Capillary blood gas → metabolic acidosis with decreased PaO2. As there is a lack of oxygen going to distal organs, cells respire anaerobically producing lactate.
ECG= Normal
Imaging
Echocardiogram - essential to demonstrate the abnormal arterial connections
CXR
Egg on a string - due to potentially narrowed upper mediastinum: cardiomegaly and increased pulmonary vascular markings
How would you initially manage TGA?
Emergency prostaglandin E1 infusion to keep the ductus arteriosus patent as a temporary solution that allows mixing of blood
Prostaglandins are high during antenatal period - so used to maintain that same state.
Correct metabolic acidosis
Emergency atrial balloon septostomy to allow mixing.
How would you manage TGA long-term?
Surgical correction, commonly arterial switch operation (ASO) is usually performed before the age of 4 weeks.
Emergency balloon atrial septostomy may be required.
Long term follow up and counselling in the future if female patients want to get pregnant.
What is Eisenmenger syndrome?
Complication of long standing L→R Shunt causes Pulmonary hypertension and eventually switches into a R→L shunt.
What are the two types of ASD?
Secundum ASD (80%) a) defect in centre of atrial septum involving the foramen ovale
Partial atrioventricular septal defect
What are the clinical signs of ASD?
None
Recurrent chest infections / wheeze
Arrhythmias (fourth decade onward)
Physical signs:
Ejection systolic murmur best heard in the upper left sternal edge - due to increased flow across the pulmonary valve because of the left to right shunt.
A fixed and widely split second heart sound - due to right ventricular stroke volume being equal in both inspiration and expiration.
