Cardiology

Question 1

Discuss normal closing times of the PFO and ductus arteriousus and age of presenation with congenital heart defects

Answer 1

PFO 3 months of age is usually closed
Ductus – 10-15 hours physiologically and 2-3 weeks anatomically

Most neonates with congenital heart defects are asymptomatic at birht. Those with duct dependant lesions usually present within the first 2 weeks of life and those with left to right shunting usually present after 4 weeks of age when pulmonary resistance has decreased and heart failure develops

Question 2

Discuss infant and child CVS compensatory responses

Answer 2

The young myocardium is ineffiecny and unable to increase its contractility in response to demand. Therefore HR is the only mechanisms to increase SV

Children develop the ability to increase contractiliy at age 8-10

If HR is not enough to maintain BP the next step is to increase SVR –> this leads to mottling, increased CRT and weak and thready pulses

Question 3

Discuss cyanosis in a child

Answer 3

For evidence cyanosis to be present there must be at least 4-5 g/DL of deoxyhaemoglobin in blood correlatuing to sats of 80-85%. In the setting of anaemia even at this level cyanosis may not be present

Central cyanosis involves the lips tongue and mucous membranes - reflects pathologic origin and is an ominous sign. If secondary to congenital heart disease may not exhibit as much as stress as would be seen from a respiratory cause. Should think cardiac if comfortably blue
Cardiac cyanosis will worsen with crying where as resp often improves
Cardiac cyanosis also will not respond well to o2 as underlying pathophys is shunting

Peripheral cyanosis (acrocyanosis) involves the hands and feats. Is a common finding in neonates caused by cold stress and peripheral vasoconstriciton can be normal or pathological

Question 4

Discuss reasons for decreased SV in infants

Answer 4

1) Hypovolaemia (most commonly secondary to dehydration)
2) CCF
3) myocarditis
4) HCOM
5) DCM
6) Pericadritis
7) Tachydysrhythmias with decreased diastolic filling times

Question 5

What formula can be used to estimate blood pressure in children older than a year

Answer 5

Newborn sytolic 60

> 1
SBP = (agex2) +70

Question 6

Discuss signs that a murmur is pathological

Answer 6

• Any diastolic
• Systolic mumurs that are louder than a grade 3 continuous or associated with a thrill
• Murmurs associated with abnormal heart sounds
• presence of cyanosis or respiratory distress
• bounding or weak pulses
• abnormalities of the ECG
• Abnormal cardiac silhouette, abnormal pulmonary vascularity or cardiomegaly on the CXR

Question 7

Discuss functional murmurs

Answer 7

All innocent or functional murmus are associated with normal ECGs and normal chest radiographs. Innocent murmurs include

1: vibratory murmur (stills)
2: pulmonary flow murmur
3: carotid bruit
4: venous hum

Pulmonic flow murmur is due to the relatively thin walls and angulation of the right and left pulmonary arteries at birht. Usually disappears by the 3rd to 6th mont. Best hear at the left upper sternal border with radiation throuigh the entire chest and axillae. Persistance past the 6 month should raise concern for pulmonary arterial stenosis

Stills murmur is seen in children aged 2-6 years of age. Best head at the left midsternal border. Murmur has a vibratory musical or twanging quality resulting from turbulent flow.

Question 8

Discuss hyperoxia test

Answer 8

Consist of assessment of a rise in Pao2 when subjected to 100% o2 -> cardiac should not rise if shunt physiology

Question 9

Discuss ABG and FBC in Congenital heart disease

Answer 9

Respiratory acidosis is often present.

HB and haematocrit are often raised due to persistent hypoxic physiology

Question 10

Discuss the CXR in childhood

Answer 10

There are three important features to look for including the cardiothoracic ratio, the cardiac shape and the degree of pulmonary marking

Cardiothoraci ratio

• Compare the largest transverse cardiac shadow diameter to the largest transverse diameter of the cardiac shadow on the PA view
• normal should be between 50-55%
• large cardiac shadow more reliably indicates a volume overload status rather than pressure overload ( ECG finding of volume overload include Right atrial enlargement, RVH)
• The cardiac size can be falsely increased in infants by the presence of the thymus seen in the mediastinum from birth until about age 5

Shape
The three cardiac silhouette patterns seen with congenital heart defects are
1) boot shaped heart of tetraology of fallot
2) egg on a string of transposition
3) snoman or figure of 8 of total anomalous pulmonary venous return

Vascular marking
- increased vascular marking are present when they can be seen in the lateral third of the lung field

Question 11

Discuss the normal pediatric ECG

Answer 11

-HR >100

-Rightward Axis due to initial increase in right sided pressures
-1week to 1 month : +110
-1-3months +70
3-3 months +60 (+10 -+120)
Adults +50 (-30 to +105)

T-wave inversions v1-3
RSR pattern in V1
Marked sinus arrhythmia
short PR interval: infants >120, 1-3 >150, 8-12 >170
Slightly peaked p -waves
Q waves in the inferior and left precordial leads

Question 12

Discuss Duct dependent lesions

Answer 12

Need PDA to preserve blood flow from the aorta to the pulmonary circulation

1) tetralogy of fallot
2) tricuspid atresia
3) pulmonary atresia
4) hypoplastic right heart syndrome
5) transposition of the great vessels

Need PDA to preserve blood from the main pulmonary artery to the systemic circulation

1) severe coarctation of the aorta
2) severe aortic stenosis
3) hypoplastic left heart

These condidion generally present from birth to the first 2-3 weeks of age when PDA is shutting
PGe1 infusion maintain PDA and are started at 0.05-0.1mic/kg/min – most signifiacnt side effect is apnoea which can affect up to 30% of cases
Avoid PGE1 when a small heart accompanies cyanosis and pulmonary oedema as this suggest TAPVD and PGE will worsen pulmonary oedema

Question 13

Discuss acyanotic lesions

Answer 13

Obstructive lesions

• pulmonary stenosis
• aortic stenosis
• coarctation of the aorta

Left to right shunt 
- VSD
-ASD
-PDA
-endocardial cushion defects 
These acyanotic lesiosn usually present within the first 6 months of life with symptoms of CHF, ASDs can remain asymptomatic

Question 14

Discuss VSD

Answer 14

Most common defect and accounts fo 20-25% of cases
Most are asymptomatic after birth due to high PVR.
When PVR decreases to the normal levels at 6-8 weeks after birth left to right shunting can then occur and the typical VSD murmur can be heard.

Small VSD will likley remain asymptomatic throughout childhood
approximatly 10% of infnats with Larger VSD present with CHF (poor feeding and poor growth) by age 2-3 months

If larger VSD are not corrected irreversible changes in the pulmonary vascularltyre may begin to occur as early as 6-12 months leading to pulmonary HTN and eventual Eisenmengers

IX: cardiomegaly with increased pulmonary vascular marking
ECG showing LVH but biventricular hypertrophy may be present

Management
All VSDs regardless of zie are at risk of bacterial endocarditis because of the high velocity of Turbulent blood flow through them as such all should be closed

Question 15

Discuss ASD

Answer 15

ASD account for 5-10% of cases of CHD
Majority of asymptomatic and 40% will spont resolve

Large ASD or those with associated comorbidites such as bronchopulmonary dysplasia can manifest with symptoms of CHF and pulmonary overcirculation

Question 16

Discuss Eisenmengers syndrome

Answer 16

Can occur with any large left to right shunt defect. Left uncorrected irreversible changes in the pulmonary arterioles leads to pulmonary vascular obstruction and pulmonary hypertension
As hypertension increases the PVR may than begin to exceed the SVR, this causes right sided pressures to exceed those on the left causing right to left shunting

This reversal in shunt direction leads to cyanosis

Question 17

Discuss coarctation of the aorta

Answer 17

Accounts for 8% of CHD and 50% have cocurrent bicuspid aortic valve
The area of coarctation can occur proximal to the ductus or distal (most common postductal type)

The severity of symptoms, the age of presentation are dependant on the location of the coarctation, the degree of narrowing and the presence of any other associated defects

preductal coarctation presents with differential cyanosis with the upper half of the body being well perfused and the lower half recieving poorly oxygenated blood from the right to left shunt from the pulmanary trunk to the aorta. When the ductus closes the patient will present with circulatory shock

Post ductal are less symptomatic presenting with systolic murmur and hypertension. If child has HTN get BP in the legs if coaractation generally have a 15-20mmhg higher BP in lower limbs

Question 18

Described tetralogy of fallot

Answer 18

Four abnormalities

1) right ventricular outflow tract obstruction (pulmonary stenosis)
2) large unrestrictive malaligned VSD
3) over-riding aorta that receives blood flow from both ventricles
4) right ventricular hypertorphy secondary to high pressure placed on the RV by the RVOFO

The age at presentation and the degree of cyanosis are directly correlated to the degree of RVOF obstruction

They will have worsening of their cyanosis during feeding apposed to respiratory causes which will likley improve

Can be duct dependent for flow to the pulomonary vessels and may require PGE1 infusion

IX: CXR shows reduced vascular markings and classical boot shaped heart, ECG shows RVH and RAX deviation

Question 19

Discuss TET spells

Answer 19

Potentially life threatening complication of tetralogy of fallot- known as a hypercyanotic or hypoxic spell

Most commonly occur in infants witha peak incidence between 2-4 months of age
Any event taht suddenly lowers the SVR such as crying or defecation, will cause a large right to left shunt through the VSD beginning the civious circle of a hypoxic spell.

The shunt causes a dramatic fall in pao2 an icnrease in pco2 and decrease in ph – these stimulate resp centres to produce hypernea (deep and rapid) which causes -ve intrathoracic pressure causing increase in systemic venous blood return to the right ventricle. This increase blood volume is shunted to the left via a combination of existing RVOT obstruction and reduced SVR

Question 20

Discuss management of TET spells

Answer 20

Overall management is to increase SVR, abolish hyperpneoea and to correct the metabolic acidosis.

Supplemental o2
increase SVR by placing him in a knee to chest position, older children may squat

Analgesics should calm the child, decrease catecholamine surge and decrease resp rate. Morphine was the historical choice but has the undesirbale possible side effect of reducing systemic vascular resistance
Both fentanyl 1mic/kg IV or 2 mic/kg IN are good option
ketamine can be considered at 1-2mg/kg IV

Ifants who do not improve with the above measures will require vasopressor support - metaraminol, phenylephrine, norad

If still no good propranolol (0.1-0.25 g/kg IV)administered slowly may reduce infundibular spasm at the RVOT

Question 21

Discuss postoperative complications of congenital heart defects

Answer 21

Early

• mediastinitis
• Cardiac failure
• Repiratory failure
• Arrythmias

Late

• Endocarditis
• Cardiac failure
• CVA
• Arryhtmai
• Cyanosis

-Post pericardiotomy syndrome is an inflammaotry pericarditis taht can occur 1-6 weeks after any surgical procedure that invovled a pericardiotomy.

Question 22

Discuss conditions at increased risk of mortality with RSV infections

Answer 22

• Cyanotic or complex congenital hear defects
• Pulmonary hypertension
• Prematurity ( especially those infants with bronchopulmonary dysplasia or chronic lung disease)
• Immunodeficiency states

Question 23

Discuss DDX of Congestive cardiac failure in children

Answer 23

Most Commonly CHD but can result from deranagement in any of the four primary determinants of normal cardiac function

1) excessive preolaoad
- large left to right shunts
- severe chronic anaemia
- hyperthroidism

2) decreased contractiltity
- myocarditis
- pericardial effusions

3) Excessive afterload
- HTN
- Left side obstructive leasions

4) Dysrythmias
- Tachy or brady dysrythmias

Other

• Toxins (can cause 2 and 4)
• Rheumatic heart
• Kawasaki disease

Question 24

Discuss presentation of CCF in children and its management

Answer 24

Problems with feeding

• sweating
• tachypnoea
• reduced volume of feeds leading to failure to thrive

Tachycardia, gallops with an s3, tachpnoea, wheeze, hepatomegaly, peripheral oedema, decreased peripheral perfusion

Management

• ABCD
• may need o2 supplementation and pressure - large left to right shunt lesiosn such as truncus arteriosus may worsen with high Fio2 so care
• May require prostaglandin
• May need pressor support
• Frusemide little evidence but considered safe 1mg/kg IM or IV

Question 25

Discuss DDX of sinus brady in children

Answer 25

Most common cause in infants and children is hypoxia and should be sort first

• Parasympathetic stimulation (suctioning)
• Metabolic (hypoxia, asphyxia, hypothermia)
• Poisoning
• Rasied ICP
• Surgical injury to SA post congenital heart surgery
• Cardiomyopathy

Management

• Remove cause
• ensure adequate ventilation
• if life threatening CPR + atropine 20mic/kg min 100mic

Question 26

Discuss SVT in children

Answer 26

Most common symptomatic dysrhythmia in infants and children - usually AVRT orthodromic
No abnormalities are found in appox 50% of cases
WPW is present in only 10-20%
Narrow QRS in 90% of SVT

Ebstein anomaly - septal and posterior leaflets of the tricuspid valve are displaced towards the apex of the right ventricle - associated with SVT and WPW 10-15% of patient with WPW have ebstein anomaly

Question 27

Discuss management of SVT in children

Answer 27

If HD untable using 0.5-1J/kg increasing to 2j/kg if not responsive

If HD stable vagal maneuvers can be used

• bag of ice and water over the face for 15-30 seconds to elicit the diving refelx
• in older children modified trandenlenburgs can be used

If unsuccessful adenosine 0.1mg/kg up to 6mg can be used increasing to 0.2mg/kg if not successful

If above is unsuccessful in a HD stable sedation with cardioversion is next option

Question 28

Discuss AF in children

Answer 28

Both a fib and a flut are rare in children and are usually associated with underlying heart conditions ( CHD, myocarditis, dig tox)

HD stability depends on rate - as with adults unstable patient should be dc cardioverted

If HD stable medications can be used to first slow the rhythm down icnluding, diltiazem, b blocker or dig - the rhythm than can be convereted and supressed with amiodarone, progcainamide or DC cardioversion

If known WPW the ABCD of drugs should be avoided
-Adenosine
-B blocker
-Calcium channel blocker
-Dig
All of these preferentially block the AV node leaving the acessary pathway to conduct atrial to the ventricles at a potentionally lethal rate
Under these condition amiodarone, procainamide or cardioversion are safe alternatives

Question 29

In children with known CHD what history question should be asked

Answer 29

Cardiac diagnosis

• congenital or acquired
• Any previous episode of decompensation ( if so are the current signs similar)

O2 issues

• Currently on home O2 ? (continous or only during feeds and sleep)
• Baseline o2 sats
• any recent need for increased o2

Medications

• Name and dose
• were any stopped recently
• any recent increase or decrease
• any new
• recent dig level if kon

Surgical procedures

• old and planned
• any complications

Question 30

Discuss IE, Myo-pericarditis

Answer 30

Look at the adult stuff not different

Question 31

Discuss kawasaki disease

Answer 31

Febrile, exanthematous multisystem vasculitis seen most commonly in children under the age of 5. Normally self limiting - leading cause of acquired heart disease in children in Western countries

Up to 20% of untreated children have some degree of coronary artery abnormalities

Cause is not well known

Male to female ratio of 1:5

Question 32

Discuss diagnostic criteria of kawasaki disease

Answer 32

Fever for at least 5 days and any four of the following
1) bilateral nonexudative bulbar conjunctival injection (bilateral scleral injection with perilimbic sparing)

2) oropharygneal mucous membrane changes (pharangeal erythema, red and cracked lips and strawberry tounge)
3) Cervical lymphadenopathy – usually unilateral

4) peripheral extremity changes- generally the last manifestation to appear - children develop an indurated oedeam of the dorsum of their hands and feet with a diffuse erythema
- periungual desquamation during convalescent phase

5) A polymorphous generalised rash (non vesicular and nonbullous) there is no specific rash that is pathognomonic for kawasaki diseaes

Question 33

Discuss incomplete kawasaki disease

Answer 33

Classic presentation and diagnositc criteria miss a number of children who present with incomplete disease

Any child less than 6 months with 7 days or greater of fever without clear source incomplete KD should be suspected – children in this age group are at greater risk of giant coronary artery aneurysm
Any child of any age with unexplained fever for >5days with only 2-3 days of criteria should be considered

In these children ESR and CRP should be performed if raised empirical treatment should be started and in hospital ECHO performed
If not raised ESR <40 and CRP <30 can be followed up in a OPD setting with serial inflammatory markers

Question 34

Discuss clinical course of Kawasaki disease and complications seen in Kawasaki

Answer 34

Postulated to be caused by an infectious agent that enters the resp tract and initiates an oligoclonal immunoglobulina A response which activates lymphocytes, cytokines and proteinases that weakn vessel walls and lead to global increase risk of aneurysm

Approx 25% of patient have diffuse myocardial inflammation - characterised by tachycardia, a gallop and non specific ST-T wave changes.

Complications

• Coronary artery disease with coronary artery aneurysm
• MI
• myocarditis

Complications usually peak 2-4 weeks after the onset of illness and are seen in 15-25% of untreated patients

Question 35

Discuss investigation and management of kawasaki disease

Answer 35

IX
-FBC -anaemia
-Platelets - marked thrombocytopenia after 1-3 weeks
-LFT
-Urine - sterial pyuria from urethritis
ECHO - coronary artery vasculitis –> generally will not have aneurysms acutely

MANAGEMENT
Main goal is to decrease the inflammation of the myocardium and coronary arteries. IVIG and high dose aspirin have an additive effect. – despite appropriate treatment 2-4% of patient will still develop coronary artery aneurysm
Can do second course of IVIG if refractory to initial – ie: ongoing fever
Pulsed methylpred 30mg/kg/day – if not affective

Current IVIG regimen involves an infusion of 2g/kg over 10-12 hours. - ideally started within the first 10 days of illness
Side effect of IVIG including 
-hypotension,
-nausdea and vomting 
-headache 
-seizure

Aspirin dose is initiate 30-50mg/kg/day (max 4 grams) orally divided into 6 hour dosing until the child is afebrile for 48-72 hours. This dose is then decreased 3-5mg/kg each day until lab results return to normal which typically occurs at 6-8 weeks
Aspirin is continued past this point only in those children with coronary artery abnormalities
-unclear if aspirin provides beniftis past that of IVIG

Steroids ?

Question 36

Discuss acute rheumatic fever

Answer 36

Most common cause of acquried heart disease in children is the result of delayed immune reaction to GAS infection throat or skin.

Immunity does not develop and unless further GAS infection can be prevented they are susceptible to recurrent attacks.

The most common presenting complaint is migratory polyarthritis which commonly involves the larger joints of the extremities

Question 37

Discuss Jones criteria

Answer 37

Evidence of preceding GAS infection

• increased or rising ASO titre or other strep antibody (anti-dnase B)
• A positive rapid GAS antigen test in a child with clinical presentation suggesting a high pretest probability of strep
• a positive throat culture for Group a b haemolytic strep

And then either 2 major or 1 major and 2 minor criteria

Major

• Pancarditis
• Migratory polyarthritis
• Erythema marginatum - smoke ring
• Subcut nodules
• Sydenhams Chorea - Jerky purposeless movement of limbs, speech impairment, emotional lability

Minor

• Fever
• monoarthralgia
• ESR>30 or CRP >3mg/dl
• Prolonged PR interval after accounting for age variability (unless carditis is a major critea)

Question 38

Discuss management of ARF

Answer 38

Prophylaxis is penicillin G administered every 21-28 days
-Adults >27 kg – 1.2 million units
Children <27kg - 600000 units evert 21-28 days

If penicillin allergy azithromycin 250mg orally daily

Prophylaxis is until age 18 but can be continued life long depending on the degree of cardiac involvement

Aspirin 50mg/kg per day in divided doses

Question 39

Discuss causes of sudden cardiac death in young athletes

Answer 39

• HOCM
• ARVD
• Prolonged QT
• Various pre-excitation
• Commotio cordis
• aortic rupture secodnary to marfans
• Myocarditis
• coronary artery disease secondary to kawasaki
• aortic stenosis

Question 40

Discuss congenital coronary artery anomalies

Answer 40

24% of caess of sudden death are due to various anomalies of the coronary arteries
The most common is the anomalous left coronary artery in whcih the left and right coronary artery arise from the right sinus - individuals with this disease have a 45% incidence of sudden death with more than 85% occuring during exercise

Congenital coronary artery hypoplasia is another uncomon cause of exercise idncued sudden death

Question 41

Discuss Marfans syndrome

Answer 41

Clinical manifestations include

• tall and slender habitus
• striae atrophicae
• disproportionately long extremities compared to the trunk
• scoliosis
• pectus excavatum or carinatum
• lens dislocation

Cardic complictions include

• mitral valve prolapse
• aortic dilation - progressive with risk of rupture

No contact sport for marfans
if known aortic root dilation nil sport at all

Question 42

Give DDX of paediatric syncope

Answer 42

1) Vasovagal - 64-73%
2) Breath holding spell (6.4%)
3) Cardiac (2.9-4.8%)
4) Neurological (2.1-4.6%)
- Seizures
- vascular events: subclavian steal, vertebrobasilar insuffieicny
- disrupted CSF circulation
- basilar migraine
5) metabolic 0.8%
6) psych 2.2-2.3
7) unknown or other (8.2-18.9%)

Question 43

Describe total anomalus pulmonary venous return

Answer 43

Pulmonary veins feed into the right atrium rather than left
Can be cyanotic depending on how many of the 4 veins feed into the right
Both right atria and ventricle can become dilated secondary to excessive fluid load

not duct dependant and can worsen with PGE1