Paed Cardio

Question 1

CHD Incidence

Answer 1

-Incidence 6-8/1000 live births
-80-85% now survive to adulthood

-VSD: 30%
-ASD: 10%
-Pulmonary stenosis: 10%
-PDA: 7%
-Coarctation: 7%
-Tetralogy of Fallot: 7%
-Aortic stenosis: 5%
-Transposition (TGA): 5%

Question 2

Cardio history for neonates

Answer 2

-Antenatal scan
-Perinatal history
-Cyanosis –consider duct dependent lesions
-Breathlessness
-Collapse, shock-consider duct dependent lesions
-Family history

Question 3

Cardio exam for neonates

Answer 3

-Dysmorphic features
-Tachycardia
-Tachypnoea
-Cyanosis
-Pulse oximetry
-Peripheral pulses
-Enlarged liver
-Murmurs

Question 4

History for infants and older children

Answer 4

-Respiratory distress
-Cyanosis
-Cyanotic spell
-Sweating during feeding/poor feeding (HF): L to R
-Poor weight gain
-Exercise intolerance
-Chest pain
-Syncope
-Palpitations

Question 5

Cardio exam for infants and older children

Answer 5

oedema extra

Question 6

Investigations in cardio problems

Answer 6

-ECG
-Echocardiogram
-Pulse oximetry
-Blood gas for acid base/ metabolic acidosis/ high lactate – for very sick patients
-Blood tests
-CXR (only symptomatic patients)
-Exercise test
-CT/MRI
-Cardiac catheter

Question 7

Classification of Congenital Heart Disease

Answer 7

-Acyanotic
=Increased pulmonary blood flow/ L >R shunt (ASD, VSD, patent ductus arteriosus, atrioventricular canal)
=Obstruction to blood flow from ventricles (coarctation of aorta, aortic stenosis, pulmonary stenosis)

-Cyanotic
=Decreased pulmonary blood flow/ R > L shunt (Tetralogy of Fallot, Tricuspid atresia, pulmonary atresia)
=Mixed blood flow (TGA, total anomalous pulmonary venous return, truncus arteriosus, hypoplastic left heart syndrome)

Question 8

Pathophysiology of L to R shunts

Answer 8

-Passage of oxygenated blood back to pulmonary circulation at atrial, ventricular or great artery level

-Results in
=Increased pulmonary blood flow
=Tendency to develop heart failure and PHT

Question 9

Pathophysiology of obstructive lesions

Answer 9

-Examples: pulmonary stenosis, aortic stenosis, coarctation of aorta
-Increased pressure in upstream vessel or chamber
-Ventricular hypertrophy
-Risk of ventricular failure (late feature)
-Critical stenosis, coarctation – duct dependent – iv Prostin

Question 10

Overall presentation of cyanotic HD

Answer 10

-Decreased pulmonary blood flow
=Oligaemic lungs
=Spelling episodes: hyperpnea (rapid/ deep breathing), irritability and prolonged crying, worsening cyanosis, disappearance or reduced intensity of heart murmur

-Mixed blood
=Plethoric lungs
=Heart failure signs: tachypnoeic

Question 11

Management of cyanotic spell

Answer 11

-ABCDE approach
-100% oxygen (pulmonary vasodilator)
-Auscultate to see if RVOTO murmur is reduced/absent to confirm diagnosis
-Holding infant in the knee-chest position, preferably in parents arm
-Morphine (IV or subcut)
=Quietens the distressed baby & reduces oxygen consumption: Suppresses respiratory centre which abolishes hypernea
-IV Access taking blood gas to check for acidosis
-IV Fluid bolus (10ml/kg) & maintenance IV fluids
-Propranolol PO 0.5mg/kg to 1mg/kg
=Myocardial depression reducing pulmonary infundibulum contraction
=Reducing tachycardia allowing more time for ventricular filling

Question 12

Overview of ASD

Answer 12

-Atrial septal defects (ASDs) are the most likely congenital heart defect to be found in adulthood. 10%
-They carry a significant mortality, with 50% of patients being dead at 50 years.
-Two types of ASDs are recognised, ostium secundum (failure of septum secundum) and ostium primum (septum primum, leads to AV valve defects and ASD). Ostium secundum are the most common. Patent foramen ovale
-Left to right shunt because left atrium higher pressure so no cyanosis but increased flow to RHS leads to right sided overload and strain so pulmonary hypertension then Eisenmenger syndrome (pulmonary pressure>systemic so shunt reverses so cyanosis)

-P: ejection mid systolic murmur, crescendo-decrescendo loudest at ULSB, fixed splitting of S2 (delayed closure of P2), dynamic precordium, parasternal heave.
=Usually asymptomatic in first 4 decades
=Asymptomatic and present in adulthood with dyspnoea, HF, stroke
=Symptomatic: SOB, difficulty feeding, poor weight gain, LRTI
= Risk of R heart failure, arrhythmias (AF and flutter), pulmonary hypertension, paradoxical embolism (RA to LA across ASD)

-I: CXR (normal or increased CTR, prominent main PA, plethoric lung fields), ECHO best from subcostal window, colour flow Doppler helpful, volume loaded right heart side), angiography

-Ostium secundum (70% of ASDs)
=Associated with Holt-Oram syndrome (tri-phalangeal thumbs)
=ECG: RBBB with RAD

-Ostium primum
=Present earlier than ostium secundum defects
=Associated with abnormal AV valves
=ECG: RBBB with LAD, prolonged PR interval

-M: closure (surgical: low mortality, good long term results/ transvenous catheter closure via femoral vein). Paediatric cardiologist for ongoing management, watchful waiting. Anticoagulants

Question 13

Overview of VSD

Answer 13

-Most common cause of congenital heart disease 30%. They close spontaneously in around 50% of cases.
-L to R so Acyanotic so pulmonary hypertension so Eisenmenger syndrome

-Aetiology
=Congenital VSDs are often association with chromosomal disorders
==Down’s syndrome
==Turner’s
==Edward’s syndrome
==Patau syndrome
==Cri-du-chat syndrome
=Congenital infections
=Acquired causes
==Post-myocardial infarction

-VSDs may be detected in utero during the routine 20 week scan. Post-natal presentations include:
=Failure to thrive, poor feeding
=Features of heart failure: Hepatomegaly, Tachypnoea, dyspnoea, Tachycardia, Pallor
=Classically a pan-systolic murmur which is louder in smaller defects, LLSB and 3/4 intercostal, may be systolic thrill on palpation
=Small defects symptoms unusual (can present in childhood), large defects may lead to HF, risk of pulmonary hypertension if not treated

-Management is clearly highly specialised
-Small VSDs that are asymptomatic often close spontaneously and simply require monitoring
-Moderate to large VSDs usually result in a degree of heart failure in the first few months
=Nutritional support
=Medication for heart failure e.g. diuretics
=Surgical closure of the defect (transvenous catheter closure via femoral vein or open heart)

-Complications
=Aortic regurgitation: due to a poorly supported right coronary cusp resulting in cusp prolapse
=Infective endocarditis (prophylactic abx for surgical procedures)
=Eisenmenger’s complex: due to prolonged pulmonary hypertension from the left-to-right shunt, results in right ventricular hypertrophy and increased right ventricular pressure. This eventually exceeds the left ventricular pressure resulting in a reversal of blood flow, this in turn results in cyanosis and clubbing. Eisenmenger’s complex is an indication for a heart-lung transplant
=Right heart failure
=Pulmonary hypertension, pregnancy is contraindicated in women with pulmonary hypertension as it carries a 30-50% risk of mortality

Question 14

Overview of Patent Ductus Arteriosus

Answer 14

-Acyanotic L to R CHD 7%, however, uncorrected can eventually result in late cyanosis in the lower extremities, termed differential cyanosis
-Connection between the pulmonary trunk and descending aorta- RHS strain leads to ventricular hypertrophy
-Usually, the ductus arteriosus closes with the first breaths due to increased pulmonary flow which enhances prostaglandins clearance. The ductus arteriosus normally stops functioning within 1-3 days of birth, and closes completely within the first 2-3 weeks of life. When it fails to close, this is called a “patent ductus arteriosus”
-More common in premature babies, born at high altitude or maternal rubella infection in the first trimester

-P: left subclavicular thrill, continuous crescendo-decrescendo machinery murmur (left clavicle, back), large volume bounding collapsing pulse wide pulse pressure, heaving apex beat, dynamic precordium. Asymptomatic small (potential for HF in adulthood), large HF
=SOB, difficulty feeding, poor weight gain, LTRI

-I: ECHO (ductal flow easily visualised using colour and continuous-wave Doppler). Hypertrophy?

-M: Monitored untill 1 year using ECHO. Indomethacin or ibuprofen (given to neonate, inhibits prostaglandin synthesis, closes the connection in the majority of cases), diuretics and SBE prophylaxis, if associated with another congenital heart defect amenable to surgery then prostaglandin E1 is useful to keep the duct open until after surgical repair (ligatiob, catheter device occlusion). Surgical after 1 year or symptomatic/ HF

Question 15

Overview of Coarctation of the Aorta

Answer 15

-7%. Coarctation of the aortic arach usually around ductus arteriosus describes a congenital narrowing of the descending aorta. It is more common in males, despite an association with Turner’s syndrome.
-Narrowing of the aorta reduces the pressure of blood flowing to the arteries that are distal to the narrowing. It increases the pressure in areas proximal to the narrowing, such as the heart and the first three branches of the aorta.

-Associations
=Turner’s syndrome
=Bicuspid aortic valve
=Berry aneurysms
=Neurofibromatosis

-P:
=Infancy: heart failure (tachypnoea, work of breathing, poor feeding, grey and floppy), neonatal collapse, weak femoral pulses (four limb blood pressure will reveal high blood pressure in the limbs supplied from arteries that come before the narrowing, and lower blood pressure in limbs that come after the narrowing)
=Adult: hypertension
=Radio-femoral delay, absent or reduced lower limb pulses, upper limb hypertension, murmur between scapulae (continuous, systolic ejection left infraclavicular area and below left scapula). Left ventricular heave (as left ventricular hypertrophy), underdeveloped left arm where reduced flow to L subclavian artery, underdevelopment of legs
=Mid systolic murmur, maximal over the back
=Apical click from the aortic valve
=Notching of the inferior border of the ribs (due to collateral vessels) is not seen in young children

-M: Surgical repair (end-to-end, patch repair, ligate ductus arteriosus), balloon angioplasty (+/- stent), operative risks (mortality <5%, spinal cord damage <1%, risk of aortic aneurysm). In cases of critical coarctation where there is a risk of heart failure and death shortly after birth Prostaglandin E is used keep the ductus arteriosus open while waiting for surgery

Question 16

Overview of Pulmonary Stenosis

Answer 16

-10% CHD
-The pulmonary valve usually consists of three leaflets that open and close to let blood out and prevent blood from returning to the heart. These leaflets can develop abnormally, becoming thickened or fused. This results in a narrow opening between the right ventricle and the pulmonary artery. This is called congenital pulmonary valve stenosis.

-Congenital pulmonary valve stenosis often occurs without any associations. It can be associated with other conditions such as:
=Tetralogy of Fallot
=William syndrome
=Noonan syndrome
=Congenital rubella syndrome

-P: Asymptomatic, exercise intolerance, arrhythmias, dizziness and fainting, SOB, Ejection systolic murmur louder on inspiration in pulmonary area. Acyanotic, RV heave (hypertrophy), thrill in pulmonary area, ejection click, delayed (soft) P2 murmur at ULSE to lung fields. Raised JVP with giant a waves

-I: ECHO

-M: Intervention if significant pressure gradient (>50 mmHg), significant elevation in RV pressure. Transcatheter approach preferred for balloon valvuloplasty via femoral vein

Question 17

Overview of Aortic Stenosis

Answer 17

-Narrow aortic valve that restricts blood flow from the left ventricle into the aorta.

-P: Mild aortic stenosis can be completely asymptomatic, discovered as an incidental murmur during a routine examination. More significant aortic stenosis can present with symptoms of fatigue, shortness of breath, dizziness and fainting. Symptoms are typically worse on exertion as the outflow from the left ventricle cannot keep up with demand. Severe aortic stenosis will present with heart failure within months of birth.
=Ejection systolic murmur heard loudest at the aortic area, which is the second intercostal space, right sternal border. It has a crescendo-decrescendo character and radiates to the carotids.
=Ejection click just before murmur, palpable thrill during systole, slow rising pulse and narrow pulse pressure

-I: ECHO, ECG, exercise testing

-M: Percutaneous balloon aortic valvoplasty, Surgical aortic valvotomy, Valve replacement

-Complications: left ventricular outflow tract obstruction, HF

Question 18

Overview of Transposition of Great Arteries

Answer 18

-Attachments of aorta and pulmonary trunk to heart swapped: two separate circulations don’t mix (R systemic, L pulmonary)
-Can be associated with VSD, Coarctation of aorta, pulmonary stenosis
-Needs SHUNT

-P: often diagnosed during pregnancy with antenatal USS, if not detected: cyanosis at or within few days of birth. A patent ductus arteriosus or ventricular septal defect can initially compensate by allowing blood to mix between the systemic circulation and the lungs, however within a few weeks of life they will develop respiratory distress, tachycardia, poor feeding, poor weight gain and sweating

-I: lactate marker for oxygenation of tissue

-M: where there is VSD allows mixing, Prostaglandin IV to maintain ductus arteriosus, balloon septostomy catheter into foramen ovale via umbilicus, inflate balloon to create large ASD to allow oxygenated blood to flow through body), open heart surgery cardiopulmonary bypass (arterial switch within few days of birth/ other corrections)

Question 19

Overview of Tetralogy of Fallot

Answer 19

-Tetralogy of Fallot (TOF) is the most common cause of cyanotic congenital heart disease. It typically presents at around 1-2 months, although may not be picked up until the baby is 6 months old

-TOF is a result of anterior malalignment of the aorticopulmonary septum. The four characteristic features are:
=Ventricular septal defect (VSD)
=Right ventricular hypertrophy
=Right ventricular outflow tract obstruction, pulmonary stenosis
=Overriding aorta

-RF: rubella, increased age of mother (40+), alcohol consumption in pregnancy, diabetic mother

-P: The severity of the right ventricular outflow tract obstruction determines the degree of cyanosis and clinical severity
=Cyanosis: unrepaired TOF infants may develop episodic hypercyanotic ‘tet’ spells due to near occlusion of the right ventricular outflow tract, features of tet spells include tachypnoea and severe cyanosis that may occasionally result in loss of consciousness, they typically occur when an infant is upset, is in pain or has a fever
=Clubbing, poor feeding, poor weight gain, ejection systolic murmur loudest in pulmonary area, tet spells
=Causes a right-to-left shunt
=Ejection systolic murmur due to pulmonary stenosis (the VSD doesn’t usually cause a murmur)

-I: ECHO with doppler flow studies. A right-sided aortic arch is seen in 25% of patients
=Chest x-ray shows a ‘boot-shaped’ heart, ECG shows right ventricular hypertrophy

-M: prostaglandin infusion can be used to maintain the ductus arteriosus. This allows blood to flow from the aorta back to the pulmonary arteries. Total surgical repair by open heart surgery is the definitive treatment, however mortality from surgery is around 5%. Prognosis depends on the severity, however it is poor without treatment. With corrective surgery, 90% of patients will live into adulthood.
surgical repair is often undertaken in two parts, cyanotic episodes may be helped by beta-blockers to reduce infundibular spasm

Question 20

What are tet spells

Answer 20

“Tet Spells” are intermittent symptomatic periods where the right to left shunt becomes temporarily worsened, precipitating a cyanotic episode. This happens when the pulmonary vascular resistance increases or the systemic resistance decreases. For example, if the child is physically exerting themselves they are generating a lot of carbon dioxide. Carbon dioxide is a vasodilator that causes systemic vasodilation and therefore reduces the systemic vascular resistance. Blood flow will choose the path of least resistance, so blood will be pumped from the right ventricle to the aorta rather than the pulmonary vessels, bypassing the lungs.

These episodes may be precipitated by waking, physical exertion or crying. The child will become irritable, cyanotic and short of breath. Severe spells can lead to reduced consciousness, seizures and potentially death.

Question 21

Tet spell treatment options

Answer 21

Older children may squat when a tet spell occurs. Younger children can be positioned with their knees to their chest. Squatting increases the systemic vascular resistance. This encourages blood to enter the pulmonary vessels.

Any medical management of a tet spell should involve an experienced paediatrician, as they can be potentially life threatening.

-Supplementary oxygen is essential in hypoxic children as hypoxia can be fatal.
-Beta blockers can relax the right ventricle and improve flow to the pulmonary vessels.
-IV fluids can increase pre-load, increasing the volume of blood flowing to the pulmonary vessels.
-Morphine can decrease respiratory drive, resulting in more effective breathing.
-Sodium bicarbonate can buffer any metabolic acidosis that occurs.
-Phenylephrine infusion can increase systemic vascular resistance.

Question 22

Pathophysiology of Tetralogy of Fallot

Answer 22

The VSD allows blood to flow between the ventricles. The term “overriding aorta” refers to the fact that the entrance to the aorta (the aortic valve) is placed further to the right than normal, above the VSD. This means that when the right ventricle contracts and sends blood upwards, the aorta is in the direction of travel of that blood, therefore a greater proportion of deoxygenated blood enters the aorta from the right side of the heart.

Stenosis of the pulmonary valve provides greater resistance against the flow of blood from the right ventricle. This encourages blood to flow through the VSD and into the aorta rather than taking the normal route into the pulmonary vessels. Therefore, the overriding aorta and pulmonary stenosis encourage blood to be shunted from the right heart to the left, causing cyanosis.

The increased strain on the muscular wall of the right ventricle as it attempts to pump blood against the resistance of the left ventricle and pulmonary stenosis causes right ventricular hypertrophy, with thickening of the heart muscle.

These cardiac abnormalities cause a right to left cardiac shunt. This means blood bypasses the child’s lungs. Blood bypassing the lungs does not become oxygenated. Deoxygenated blood entering the systemic circulation causes cyanosis. The degree to which this happens is related mostly to the severity of the patients pulmonary stenosis.

Question 23

Heart murmurs

Answer 23

-Ejection systolic
=Louder on expiration: aortic stenosis, hypertrophic obstructive cardiomyopathy
=Louder on inspiration: pulmonary stenosis, atrial septal defect
=Tetralogy of Fallot

-Holosystolic (pansystolic)
=Mitral/tricuspid regurgitation (high-pitched and ‘blowing’ in character): tricuspid regurgitation becomes louder during inspiration, unlike mitral reguritation, during inspiration, the venous blood flow into the right atrium and ventricle are increased → increases the stroke volume of the right ventricle during systole
=Ventricular septal defect (‘harsh’ in character)

-Late systolic
=Mitral valve prolapse
=Coarctation of aorta

-Early diastolic
=Aortic regurgitation (high-pitched and ‘blowing’ in character)
=Graham-Steel murmur (pulmonary regurgitation, again high-pitched and ‘blowing’ in character)

-Mid-late diastolic
=Mitral stenosis (‘rumbling’ in character)
=Austin-Flint murmur (severe aortic regurgitation, again is ‘rumbling’ in character)

-Continuous machine-like murmur
=Patent ductus arteriosus

-Right sided murmur: heard best on inspiration
-Left sided murmur: heard best on expiration