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Cardiology Flashcards

1
Q

Causes of superior axis on ECG

A

AVSD, tricuspid atresia, Ebsteins anomaly, Noonans syndrome, Wolff-Parkinson-White syndrome and in <1% of normals

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2
Q

Interrupted aortic arch, cleft palate and hypocalcaemia

A

22q11.2 deletion

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3
Q

Hypercyanotic (tet) spells are characterised by?

A
  • paroxysms of tachypnoea
  • prolonged crying
  • intense cyanosis
  • decreased intensity of the murmur of pulmonic stenosis (ejection systolic) due to greater obstruction
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4
Q

Causes of prolonged QTc?

A 
Jervell-Lange-Nielsen syndrome
CNS/Head injury
Hypokalaemia
Erythromycin
Hypocalcaemia
Hypomagnesemia
Adrenal insufficiency
Hypothermia
Quinidine
Phaeochromocytoma
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5
Q

Examples of calcium channel blockers

A

Amlodipine, nifidepine, verapamil

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6
Q

Describe the presentation and murmur of Ebstein’s Anomaly

A
  • If severe, presents with cyanosis at birth
  • If mild, presents with SOB and fatigue in childhood
  • Murmur: split S2 and loud systolic murmur at the LLSE due to tricuspid regurgitation
  • Associated with maternal lithium use
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7
Q

What ECG features would you find in Ebstein’s Anomaly?

A

RBBB, RAH, 1st degree AV block, delta wave (WPW)

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8
Q

What CXR findings would you find in Ebstein’s Anomaly?

A

Wall-to-wall cardiomegaly, decreased pulmonary vascular markings, raised apex of heart

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9
Q

What is the management of Ebstein’s Anomaly?

A
  • If severe with cyanosis at birth - resus, prostaglandin, I+V
  • Diuretics, digoxin for overload/arrhythmia
  • SVT - adenosine, b-blocker, ablation
  • Tricuspid repair or replacement
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10
Q

Which cardiac conditions is most commonly associated with neurofibromatosis?

A

Pulmonary stenosis is more common than expected in NF1. Other cardiac malformations may also be unusually frequent among NF1 patients.

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11
Q

Most common cardiac anomalies in William’s syndrome?

A

Supravalvular aortic stenosis (most common), peripheral pulmonary stenosis, and supravalvular pulmonary artery stenosis

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12
Q

What provides the strongest stimulus for postnatal closure of the ductus arteriosus in a term infant?

A
  • Increased systemic oxygen saturation
  • Normally, functional closure by 15 hours in healthy infants born at term
  • First breath -> increase in partial pressure of oxygen -> abrupt contraction of the muscular wall of the ductus arteriosus
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13
Q

Qp:Qs ratio

A

(PV - PA)

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14
Q

To what event in the cardiac cycle does the third heart sound relate?

A

Rapid ventricular filling e.g. in any condition that causes LV volume overload or dilatation (congestive heart failure and normal pregnancy)

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15
Q

What causes wide splitting of S2?

A

ASD, PS (pressure overload), Ebstein anomaly, TAPVR, RBBB (electrical delay), MR (early aortic closure)

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16
Q

What causes an accentuated pulmonary component of S2 with narrow splitting?

A

Pulmonary hypertension

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17
Q

What causes a single second heart sound?

A
  • Pulmonary or aortic atresia or severe stenosis
  • Truncus arteriosus
  • Transposition of the great arteries
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18
Q

How do you calculate pulmonary vascular resistance?

A

PVR = (mean PA pressure - mean LA pressure)/Qp

PVR is measured in woods units
Qp = flow e.g. 4L/min of cardiac output
Pulmonary hypertension = >3 woods units
Normal systemic vascular resistance = 10-14 (> 14 abnormal)

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19
Q

What cardiac medications should not be used in WPW due to the risk of re-entry tachycardia?

A

Digoxin and calcium channel blockers

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20
Q

What are the causes of LAD on ECG?

A
  • LVH esp volume overload

- L anterior hemiblock = tricuspid atresia, AV canal defect, congenitally corrected TGA

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21
Q

Describe the physiology behind a tet spell

A
  • Tet spells lead to a decrease in the pulm stenosis murmur
  • Decr SVR leads to hyperpnoea to inc venous return to the heart
  • This causes a R to L shunt across VSD, which causes further hypoxia
  • Need to increase L sided pressure e.g. squatting, so that blood goes through PA rather than across VSD
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22
Q

Why does primum ASD cause a LAD?

A

Because the AV node is displaced posteriorly

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23
Q

What is the mean pulmonary artery wedge pressure an indirect measure of?

A

The mean left atrial pressure

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24
Q

What is the abnormality in the cardiac action potential which results in QT prolongation in LQT1, LQT2 and LQT5?

A
  • Prolonged potassium efflux
  • The end result is an overload of myocardial cells with positively charged ions during ventricular repolarisation, resulting in a prolonged interval.
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25
Q

How do you calculate stroke volume?

A

EDV - ESV

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26
Q

How do you calculate ejection fraction?

A 
 EDV Normal = 55-60% (~ double the fractional shortening, which is calculated the same way but using diameter of short axis of ventricle -> quick and easy compared to EF calculation on ECHO)
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27
Q

What factors affect ventricular preload?

A
  • Inc total venous blood volume = inc venous return = inc preload
  • Dec venous compliance = inc venous pressure = inc preload
  • Inc atrial inotropy/contraction
  • Inc afterload = more blood left in heart after each contraction = inc preload
  • Decr HR = more time for heart to fill
  • Decr ventricular inotropy/contraction = inc end systolic volume = heart fills to greater degree = more contraction
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28
Q

What is the Frank-Starling law?

A
  • Increased ventricular filling increases stroke volume (as it increases preload or LVEDP)
  • This is because myocytes stretch more, and therefore contract back harder. Does not use more ATP
  • So inc venous return = inc EDV = inc stroke volume
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29
Q

What is ventricular afterload?

A
  • Ventricular afterload is related the pressure the ventricle must generate in order to eject blood into the aorta
  • Increased afterload leads to decreased velocity of contraction, as it takes longer for ventricle to overcome the pressure
  • Inc afterload causes Starling curve to move downwards = decreased SV and increased preload
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30
Q

What is the effect of afterload on stroke volume?

A
  • Inc afterload causes decr stroke volume -> inc preload

- Decr afterload causes incr stroke volume -> decr preload

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31
Q

What is the main contributor to the oedema found in congestive heart failure?

A

Sodium retention via the renin-angiotensin-aldosterone pathway (due to poor cardiac output leading to reduced perfusion of juxtaglomerular apparatus)

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32
Q

What ECG change would you see in a primum atrial defect?

A
  • The left axis deviation is suggestive of ostium primum ASD (due to AV node being displaced posteriorly and inferiorly, and atrial and/or AV nodal conduction often is delayed)
  • May be evidence of RBBB with RSR pattern in lead V1.
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33
Q

What causes an S3 heart sound?

A
  • A S3 heart sound is produced during passive left ventricular filling when blood strikes a compliant LV.
  • “ventricular gallop”
  • Just after S2
  • Can be a normal finding in children, but usually indicates systolic heart failure in adults (due to dilated ventricle)
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34
Q

What causes an S4 heart sound?

A
  • “atrial gallop”
  • Just before S1
  • When atria contracts to force blood into LV
  • If LV non-compliant (stiff or hypertrophic), then blood forced through AV valves and S4 produced by blood striking LV
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35
Q

Causes of myocarditis?

A
  • Infection: adenovirus, enterovirus, parvovirus, Chagas, zika, other viruses, mycoplasma
  • Meds: doxorubicin, antibiotics, tricyclic antidepressants, phenytoin
  • Autoimmune: coeliac, lupus, Kawasaki, Crohns, sarcoid
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36
Q

Which drugs can prolong the QTc?

A

Antiarrhythmics e.g. amiodarone, TCAs, antipsychotics (haloperidol, quetiapine), anti-infectives (clarithromycin, fluconazole, erythromycin).

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37
Q

Paradoxical splitting of S2 in expiration occurs in?

A

Severe aortic stenosis

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38
Q

Discuss coronary artery fistulas

A
  • A fistula from one of the coronary arteries directly into the RV (most common) or into RA
  • Continuous murmur along LLSE, maximal in diastole and has very high-pitched components. A continuous thrill may be palpable.
  • Specific diagnosis may require cardiac catheterisation, angiocardiography or further cardiac imaging i.e. CT scan.
  • Treatment involves ligation, specific surgical repair or coil occlusion.
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39
Q

Discuss the differences in KCNQ1, KCNH2 and SCN5A gene mutations

A
  • All cause long QT syndrome
  • Risk for cardiac events is greater in LQT mutations in the
    KCNQ1 (63%) or KCNH2 gene (46%), compared to those
    with mutations in the SCN5A gene (18%).
  • Mutations in KCNQ1 experience most episodes during
    exercise and rarely during rest or sleep.
  • Mutations in KCNH2 and SCN5A are more likely to have
    episodes during rest or sleep and rarely during exercise
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40
Q

Differential diagnoses for infants that are critically ill

in the first 24 hours include?

A
  • Valve problems (e.g. Ebstein’s, absent pulmonary valve syndrome)
  • Obstructed TAPVD
  • ‘Early’ duct dependent circulation
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41
Q

What are causes of significant cardiomegaly at birth?

A
  • Ebstein’s anomaly - wall to wall heart
  • Fetal cardiomyopathy
  • Pompe disease (GSD type 2)
  • AVM
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42
Q

Infant with profound cyanosis without respiratory distress… suspect?

A

Transposition of the great arteries, sats usually 50-70%

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43
Q

Discuss Brugada syndrome

A
  • Can cause syncope associated with fever or usually at rest, sleep, or after a heavy meal (vagal nerve activation)
  • Risk sudden cardiac death. AD.
  • Can lead to VF or polymorphic VT secondary to reentry loop, may need ICD
  • SCN5A mutation (encodes cardiac sodium channels), can overlap with LQT type 3
  • Characteristic ECG: ST elevation in leads V1-V3 with a right bundle branch block (RBBB) appearance
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44
Q

ECG findings in HOCM?

A

Voltage criteria for LVH with associated ST segment repolarisation abnormalities are classical ECG findings in hypertrophic cardiomyopathy

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45
Q

A long systolic murmur at the left sternal edge?

A

Could represent a VSD, TOF, Still’s, or TR

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46
Q

Management of VT with pulse and:

  • Shocked
  • Not shocked?
A
  • Shocked: DC synchronous shock 2J/kg, then 4J/kg, then amiodarone, then repeat 2J/kg
  • Not shocked: amiodarone 5mg/ over 1-4 hrs, if persistent then consider synchronous shock
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47
Q

Treatment of bradycardia in shocked child:

  • Due to vagal overactivity
  • Not due to vagal overactivity
A
  • Vagal overactivity: atropine 20mcg/kg

- Not due to vagal overactivity: adrenaline 10mcg/kg

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48
Q

Management of SVT:

  • With shock
  • Without shock
A
  • With shock: Synchronous DC shock 1J/kg, then 2J/kg, consider amiodarone
  • Without shock: vagal maneuvers, then adenosine 100mcg/kg, 2min later 200mcg/kg, 2 min later 300mcg/kg, then consider 400-500mcg/kg or synchronous shock or amiodarone
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49
Q

Endocardial fibroelastosis is associated with which infection in pregnancy, and what are the features?

A
  • Mumps
  • Aortic stenosis, hypoplastic left heart and aortic coarctation
  • Echocardiogram shows opaque white fibroelastic thickening of the endocardial surface of the heart.
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50
Q

What is the mechanism of action of digoxin?

A
  • Digoxin, a Na/K/ATPase pump inhibitor, depresses the SA and AV nodes, prolongs refractiveness and slows conduction
  • Side effects of overdose: arrhythmia, hyperkalaemia
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51
Q

Medication used in long QT syndrome?

A

Propranolol, a non-selective beta blocker, is the pharmacological treatment of choice for long QT syndrome and is effective in 70% of cases in preventing ventricular tachyarrhythmias.

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52
Q

Medication used in cardiomyopathy to prevent arrhythmias?

A

Amiodarone, a class III agent, inhibits nodal function as wells a cardiac conduction and prolongs the refractory period. It has been shown to suppress both supraventricular and ventricular arrhythmias in all forms of cardiomyopathy (dilated, hypertrophic and restrictive).

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53
Q

Medication used in atrial flutter?

A

Sotalol

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54
Q

Medication used in WPW?

A

Flecainide, a sodium channel blocker and class 1c agent, slows conduction velocity in the accessory pathway in WPW and can be used to terminate supraventricular tachycardias in this condition.

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55
Q

How can you calculate the cardiac output?

A

CO = oxygen consumption (ml/min) / arteriovenous oxygen difference

CO = VO2/(A-V)

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56
Q

RsR in V1 vs RsR in V6

A
  • V1 = partial RBBB

- V6 = partial LBBB (rarely seen in paeds)

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57
Q

Partial vs complete bundle branch block

A

If QRS is prolonged (>0.12) then complete BBB. If QRS is normal then partial RBBB

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58
Q

What are the findings in a Still’s murmur?

A
  • Vibratory ESM loudest at LUSE and LLSE, resolves with extension of the neck, almost disappears with sitting
  • Due to aortic leaflet vibration
  • Normal CXR, normal ECG
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59
Q

Tall R wave V1 with deep S wave in V6 indicates?

A
  • RVH
  • Normal R in V1: 2-16 sq
  • Normal S in V6: 0-7 sq
  • Severe RVH develop ST and T wave inversion with ST depression
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60
Q

Upright T waves in V1 between day 4 age and 4yo indicates?

A
  • Pathological RVH
  • Allowed to be upright until day 4
  • Severe RVH the T wave goes down again due to strain
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61
Q

Large P waves indicate?

A
  • If tall = p pulmonale = RAH, >3mm tall

- If bifid or wave (V1) = p mitrale = LAH, >2.5 sq wide = >0.10 sec

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62
Q

Causes of RVH on ECG?

A
  • ASD
  • Large VSD with pulmonary hypertension
  • ToF
  • Pulmonary stenosis
  • TAPVR
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63
Q

What are the findings of LVH on ECG?

A
  • S in V1 + R in V5 or V6 >40mm total
  • Prolonged QRS or flat T waves in V5 and V6 (or inverted if severe LVH)
  • Q waves in II, III, aVF, V5-6
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64
Q

Causes of LVH on ECG?

A
  • Aortic stenosis
  • Systemic hypertension
  • Large VSD
  • PDA
  • Cardiomyopathy
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65
Q

Familial causes of prolonged QT

A
  • Romano Ward
  • Jervell and Lange Nielsen syndromes
    (others = electrolytes, drugs, metabolic)
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66
Q

TAPVD on ECG?

A

RAD, RVH, RAH

Cyanotic child

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67
Q

Causes of RAH on ECG?

A
  • ASD
  • Tricuspid stenosis or atresia
  • Tricuspid regurg
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68
Q

Causes of LAH on ECG?

A
  • Mitral stenosis or atresia
  • Mitral regurg
  • L-R shunt with large VSD causing increased return to LA
  • PDA (inc R volume loading)
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69
Q

ECG findings of incomplete AV canal defect or ostium primum defect?

A
  • LAD (due to shift of SA node)
  • RVH +/- RAH
  • Incomplete RBBB
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70
Q

When are Q waves on ECG normal?

A

Normal if narrow and in inferior or lateral leads

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71
Q

Causes of abnormal ST segment?

A

> 1mm in limb leads, >2mm in V2-V4

Pericarditis, myocarditis, MI, electrolyte abnormalities

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72
Q

Which CHD preset as critically ill in the first 24 hours?

A
  • Valve regurgitation, especially Ebstein’s and absent pulmonary valve syndrome (with large PA and pulm valve regurg)
  • Obstructed TAPVD (only obstructed)
  • Early duct-dependant presentation if duct closes very early
  • Respiratory distress in first 24 hours is usually not a cardiac causes -> resp disease
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73
Q

Discuss the findings in Ebstein’s

A
  • Sick neonate, occ diagnosed in older children
  • CXR: wall to wall heart (mostly RA), cardiomegaly, lung hypoplasia
  • ECG: delta waves (WPW), RVH, RAD, RAH
  • Due to atrialisation, tricuspid valve displaced down into RV causing small RV
  • Regurgitation into RA and shunting across PFO (patent due to high RA pressures) or ASD + small RV leads to heart failure
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74
Q

Discuss the findings in TAPVD

A
  • Sick neonate if obstructed, with pulmonary hypertension and pulm oedema
  • Cyanosis due to mixing of blood -> ASD
  • CXR: plethoric lung fields R>L, normal cardiac size, can affect lungs asymmetrically. Pulm oedema if obstructed
  • ECG: RVH and RAH
  • Due to PV return to the SVC (supracardiac), RA via coronary sinus (cardiac), or via liver or IVC (infracardiac)
  • Must have associated ASD otherwise not compatible with survival, small ASD can lead to shock
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75
Q

Supracardiac TAPVD on CXR

A
  • Snowman sign

- Widened mediastinum, flattened diaphragm, increased lung vascularity

76
Q

In which type of TAPVD does obstruction most commonly occur?

A

Infracardiac (PV return to liver or IVC)

77
Q

Which CHD present within the first 24 hrs with:

  • A murmur
  • Cyanosis
A
  • Murmur: aortic stenosis, pulmonary stenosis, mitral regurg, tricuspid regurg. Not usually ASD or VSDs (as pulm vasc resistance still high)
  • Cyanosis: TGA, single ventricle, mixing (or early duct dependent)
78
Q

Which CHD present between 24hrs - 2 weeks:

  • Dependent on PDA for pulm blood flow
  • Dependent on PDA for systemic blood flow
  • Dependent on PDA for mixing
A
  • Pulm (blue): pulm atresia or stenosis, single ventricle with PA or PS
  • Systemic (pale and shocked): aortic atresia or stenosis, HLHS, critical coarctation
  • Mixing (cyanosis): TGA
79
Q

Duct-dependent cyanotic heart disease:

  • Oligaemic lung fields
  • Mildly plethoric lung fields
  • Congestion
  • Massive cardiomegaly
A
  • Oligaemic lung fields - pulm atresia or stenosis
  • Mildly plethoric lung fields - TGA
  • Congestion - TAPVD with obstruction + pulm oedema
  • Massive cardiomegaly - Ebstein’s
80
Q

CXR findings in TGA

A
  • Narrow mediastinum as aorta and PA are orientated ant-posteriorly (aorta = ant)
  • Egg on a string
  • Mildly plethoric lung fields
81
Q

What is levo-TGA

A
  • Congenitally corrected TGA
  • RV connected to aorta, LV connected to PA however ventricles have switched over
  • Not cyanotic
  • Over time develop RVH and heart failure as R sided heart and valves not built to withstand high systemic pressures
  • ECG: First degree heart block, left axis, deep “Q” waves in V1 and no “Q” waves in V5-6
82
Q

Which CHD present between 2-6 weeks?

A
  • VSD, PDA, AVSD
  • Truncus
  • ToF with pulmonary atresia
  • Present with congestive heart failure once pulm vascular resistance has dropped, leading to excess pulmonary blood flow
  • Tachypnoea, poor feeding, poor weight gain, hepatomegaly
83
Q

CXR findings in partial anomalous pulmonary venous drainage?

A

Scimitar sign, where right pulmonary veins join into IVC junction

84
Q

Findings in coarctation?

A
  • Murmur heard posteriorly between scapula
  • Diminished femoral pulses
  • Hypertension
  • Associated with bicuspid aortic valve
85
Q

Discuss venous hum murmur

A
  • Continuous murmur, due to venous return to the heart
  • Accentuated in diastole
  • DDx: PDA
  • Varies with posture and head movement, turn head to side and compress neck vein -> murmur resolves
86
Q

Indications for cardiac catheterisation?

A
  • Haemodynamics - flow, pressure, shunting, resistance, primary pulmonary hypertension
  • Angiography - anatomy, can see extra-cardiac (missed on ECHO)
  • Interventional e.g. balloon septostomy
87
Q

Normal cardiac catheterisation data?

A
  • Sats R side = ~75%, L side = ~95%
  • Pressure RA 5, RV 25/5, PA 25/10
  • Pressure LA 6, LV 95/10, Ao 100/60
88
Q

Triad of symptoms in aortic stenosis

A
  • Breathlessness (restricted CO)
  • Syncope
  • Chest pain (lack of coronary blood flow)
89
Q

Risks of cardiac catheterisation

A
  • Common - fever, haematoma at groin, transient vessel occlusion, transient arrhythmia
  • Uncommon (<1%) - stroke, seizure, allergic reaction, cardiac perforation
  • Mortality <1%
  • Radiation exposure
90
Q

Findings of RVH on ECG

A
  • Tall R in V1, deep S in V6
  • rSr in V1 or V2 without widening of QRS
  • q wave in V1 or V2
  • Pure R wave V1 and V2 +/- ST changes = strain
91
Q

What is the significance of a Q wave in V1?

A
  • Pathological (except occasional newborns)

- L-TGA, single ventricle, severe RVH or anterior MI (deep and wide)

92
Q

Biventricular hypertrophy on ECG

A
  • Large R and S in V3

- Make sure leads not at half gain

93
Q

AVSD on ECG

A
  • LAD or superior axis
  • LAH and RAH
  • LVH and RVH
    (note: truncus will have BVH but normal axis)
94
Q

ToF ECG findings pre and post op

A
  • RAD, rsR pattern, RVH (tall R V1, deep S V6)

- Post-op: RBBB

95
Q

ECG in TGA

A
  • Early newborn - normal ECG

- Later - RAD, RVH

96
Q

ECG in Ebstein’s

A
  • RAH, RAD
  • No/small RV forces – commonly will have RBBB
  • Pre-excitation - delta waves/WPW
  • Absent “Q” waves in V6
  • Risk of SVT
97
Q

ECG in tricuspid atresia

A
  • LAD, low right atrial axis
  • Can have LAH, RAH, or combined
  • No RV forces - lack of R wave in V1
98
Q

ECG in coarctation

A
  • LVH pattern (tall R waves in left chest leads & deep S waves in right chest leads) with strain lateral and inferior
  • Note: in neonate have RVH
99
Q

Pulmonary atresia with intact septum on ECG

A
  • RAD
  • RAH
  • Loss of right ventricular predominance (small R wave V1) as RV not formed
100
Q

Significance of a negative (upside down) p wave in lead I?

A
  • Leads reversed or situs inversus, or ectopic atrial tachycardia
  • Dextrocardia will have lack of R wave progression
101
Q

Significance of ALCAPA

A
  • Anomalous L coronary artery from pulmonary artery
  • Leads to ischaemia due to de-oxygenated blood supplying LV
  • Ischaemic pattern on ECG with ST elevation inferior leads and ST depression V4-V6
102
Q

Hypoplatic L heart on ECG

A
  • RAD, RVH

- Lack of LV forces (no R wave in V5-V6)

103
Q

Truncus arteriosus on ECG

A
  • Normal axis

- Biventricular hypertrophy

104
Q

TAPVD on ECG

A
  • RAH and RVH

- RAD

105
Q

Dextrocardia on ECG

A
  • Low voltages V3-V6 (as placed on L side chest
  • Negative p wave, QRS complex, T wave in lead I
  • Absent R wave progression chest leads
  • RAD
106
Q

How do you calculate PVR and SVR?

A 
PVR = mean PAp - mean LAp / Qp
SVR = mean Aop - mean RAp / Qs
107
Q

What are the risks post AV dilatation?

A
  • High risk
  • Aortic regurgitation (10%)
  • Mitral valve damage
  • Ventricular arrhythmia
  • Risk of recurrence of stenosis with time after balloon valvuloplasty (note: low risk recurrent with pulmonary valve)
108
Q

Why do we close ASDs in childhood?

A
  • No inc in pressure, is a volume-load into RV
  • Close to prevent arrhythmia and heart failure in adulthood
  • Can occasionally cause FTT in child
  • > 50% amenable to transcatheter closure
109
Q

What is the risk of a perimembranous VSD?

A

Lies close to aortic valve, risk of aortic regurgitation

110
Q

Cardiac issues in Williams?

A

Supravalvular aortic stenosis and supravalvular pulmonary stenosis

111
Q

Cardiac issues in Noonans?

A

Pulmonary stenosis

112
Q

Types of SVT

A
  • Accessory pathway (reentry tachycardia, most common cause SVT in paeds)
  • AV nodal reentry
  • Ectopic atrial tachycardia (from ectopic focus)
  • Atrial flutter
  • Atrial fibrillation
113
Q

Discuss accessory pathway tachycardia

A
  • AV reentry tachycardia, small accessory muscular pathway
  • Atria - AV nodes - ventricle - accessory pathway
  • Can be orthodromic (most common) or antidromic
  • Rate varies according to age (HR slows as pathway becomes longer) > 300bpm infant, >200bpm older children
  • ECG: narrow complex tachycardia, retrograde p waves
114
Q

Discuss orthodromic AVRT

A
  • Narrow complex tachycardia ddx AVNRT, ectopic atrial tachycardia
  • Retrograde p waves (as reversed direction)
  • Normal QRS pathology
  • More common than antidromic
  • Signal goes from SA nodes through AV node to the ventricles, then backwards up the accessory pathway
  • Tx: block AV node - adenosine (acute), propranolol (chronic) or block accessory pathway - flecainide
115
Q

Discuss antidromic AVRT

A
  • Broad complex tachycardia ddx VT
  • Signal goes from SA node through accessory pathway to the ventricle, then backwards through AV node (reversed)
  • Less common than orthodromic
  • Bundle branch block morphology of QRS (right AP = LBBB, left AP = RBBB) due to early repolarization
  • Tx: block accessory pathway - flecainide, sotalol. Not digoxin (propagates AP conduction by blocking AV node)
116
Q

Discuss Wolff Parkinson White

A
  • Ventricular pre-excitation (at rest) and paroxysmal tachycardia (SVT)
  • Simultaneous AV conduction via AV node and via accessory pathway (reason for short PR as no delay through AV node) - called Bundle of Kent
  • L side (type A) accessory pathway more common
  • May be orthodromic (most common) or antidromic
  • Spontaneous AF may occur (uncommon) -> risk of VT and VF and sudden death
  • ECG: short PR, delta wave, QRS prolongation
  • Tx: ablation of accessory pathway
117
Q

What is AV nodal reentry tachycardia?

A
  • Reentry circuit around the AV node
  • Slow pathway antegrade, fast pathway retrograde
  • Simultaneous deploratisation of the atria and ventricles - p waves buried in QRS
  • Rare before school, occurs later in childhood
  • Sx: palpitations, dizziness, dyspnoea, fainting, multiple episodes/day
  • HR 150-200bpm
  • No clear trigger, rarely life-threatening
  • Tx: ablation of slow pathway, vagal maneuvers to temporarily block AV node, propranolol to block AV node, adenosine doesn’t work
118
Q

Discuss ectopic atrial tachycardia

A
  • Non-sinus atrial focus with enhanced automaticity
  • Can cause sustained tachycardia which can be asymptomatic but then present with ventricular dysfunction and cardiomyopathy (SOB, fatigue, CHF)
  • Warm up period, tachycardia with change in p wave morphology (e.g. inverted), then cool down period
  • Up to 300bpm infants, 250bpm children
  • Don’t usually respond to vagal maneuvers (doesn’t involve AV node), may briefly respond to adenosine
  • Tx: slow cardiac conduction: sotalol, flecainide, propranolol
119
Q

Discuss atrial flutter

A
  • Macro reentry circuit within RA
  • Occurs in neonates (normal heart) or children with CHD e.g. Ebstein’s
  • Continuous electrical activity in atrium produces flutter waves with sawtooth pattern
  • Can give adenosine to slow rate down to see sawtooth waves, but adenosine cannot treat flutter
  • Tx: cardioversion: amiodarone or sotalol, rate control: digoxin or B-blocker
120
Q

Treatment of atrial flutter?

A
  • Medical cardioversion: amiodarone or sotalol

- Rate control: digoxin or B-blocker

121
Q

Discuss ventricular tachycardia

A
  • Can be idiopathic (arising from ectopic focus) or re-entrant (scar tissue, post op CHD surgery)
  • Broad complex tachycardia
  • Capture beats seen within tachycardia = VT
  • Complete AV dissociation shows beats are originating in ventricle
122
Q

Discuss fasicular VT

A
  • Reentry tachycardia within left bundle, causes RBBB
  • Narrow complex QRS
  • Can be mistaken for SVT: does not respond to ice or adenosine, has infrequent response to amiodarone
  • Tx: slow IV verapamil (usually contraindicated in children)
123
Q

Why is verapamil usually contraindicated in children?

A
  • Calcium channel blocker

- Causes vasodilation leading to low output and cardiac arrest

124
Q

Most common infectious causes of myocarditis?

A
  • Coxsackie B (North America) + other viral
  • Chagas (protozoa, South America) - see amastigote in heart muscle cells
  • Lyme disease
125
Q

Non infective causes of myocarditis?

A
  • SLE
  • Polymyositis
  • Drug-induced - hypersensitivity reaction - eosinophils
  • Giant cell arteritis - macrophages
126
Q

Symptoms of myocarditis?

A
  • Positional chest pain
  • Arrhythmia - inflammation of pacemaker cells
  • Fatigue, fever, SOB
  • Can develop heart failure and oedema
127
Q

Investigations in myocarditis?

A
  • Raised CK and troponin
  • ECG: sinus tachycardia, T wave inversions, saddle ST elevation
  • CXR: cardiomegaly
  • ECHO: inflammation of myocardium
128
Q

Causes of pericarditis?

A
  • Idiopathic
  • Viral e.g. coxsackie B
  • Uremic pericarditis
  • Dressler syndrome (post MI)
  • RA, SLE, scleroderma
  • Radiation
  • Meds e.g. penicillin, anticonvulsants
129
Q

Pathogenesis of pericarditis

A
  • Inflammation of the pericardium leads to fluid and inflammatory cell accumulation
  • Can develop pericardial effusion due to inability to reabsorb fluid. If this becomes large can lead to tamponade and reduced CO
  • Fibrosis of pericardium secondary to inflammation leads to thickening + stiffening -> constrictive pericarditis. Stroke volume decreases, HR increases to compensate
130
Q

Symptoms/signs of pericarditis

A
  • Fever
  • Chest pain, worse with inspiration, improves with sitting up and leaning forwards
  • Friction rub
  • Large effusion: quiet breath sounds, SOB, low BP due to reduced CO
  • ECG: ST elevation and PR depression -> flattened T waves -> inverted T waves -> normalises over weeks. Effusions lead to reduced QRS voltages
  • CXR: cardiomegaly, effusion
  • Tx: analgesia, colchicine (reduces recurrence)
131
Q

Most common causes of infective endocarditis?

A
  • Streptococci viridans (alpha haemolytic strep) most common. Lives in mouth, low virulence, attacks valves with previous damage, leads to small valvular vegetations
  • Staph aureus - high virulence, attacks healthy valves, usually due to IV drug use
  • Staph epidermidis - prosthetic valves
  • Enterococcus faecalis, strep bovis - UC, colorectal cancer
  • HACEK organisms (gram -ve)
  • Fungal
132
Q

Signs, symptoms of infective endocarditis

A
  • Fever
  • New murmur
  • Septic emboli - splinter haemorrhage, roth spots, janeway lesions, osler’s nodes, GN
133
Q

Discuss catecholaminergic VT

A
  • AD, rare but dangerous, high risk syncope and death
  • Normal ECG at rest
  • Polymorphic VT with catecholamines (exogenous or endogenous) eg with exercise, adrenaline, scared/excited
  • Recurrent syncope with exercise = red flag
  • Require beta blocker
134
Q

Discuss long QT syndrome

A
  • AD, variable penetrance, 17 genes
  • QTc >0.46m (M) and >0.47 (F)
  • Abnormally long repolarisation
  • Risk of polymorphic VT - torsades de pointes
  • LQT1 (KCNQ1) - swimming, diving, usually young boys - K+ channel
  • LQT2 (KCNH2) - strong stimulus e.g. alarm clock, post partum, surprises, usually young women - K+ channel
  • LQT3 (SCN5A) - sudden death in sleep - Na+ channel
  • Can also be caused by meds, electrolyte abnormality
  • Romano-Ward, AD, LQT1-6
  • Jervell and Lange Nielsen, AR, bilat SNHL - KCNQ1
135
Q

1st degree heart block

A
  • PR prolongation with 1:1 AV conduction
  • Secondary to ASD, rheumatic fever
  • Rarely progresses to higher degree heart block
136
Q

2nd degree heart block

A
  • Mobitz I: (Wenckebach) progressive elongation of PR interval until dropped beat occurs, usually benign and resolves, transient nocturnal Wenckebach normal in children
  • Mobitz II: regular PR interval with intermittent sudden failure and dropped beat, rare, potential to progress to complete heart block, seen post cardiac surgery
137
Q

3rd degree heart block

A
  • Complete AV dissociation
  • Manifests as regular bradycardia
  • Causes: anti-Ro/Anti-La (SLE, Sjogrens), CHD (L-TGA, heterotaxy), post-cardiac surgery (AVSD)
  • Need pacemaker if: HR <55 as infant, ventricular dysfunction, broad QRS complexes, ventricular ectopy
  • Tx: transvenous pacing line until pacemaker insertion
138
Q

Class I antiarrhythmics

A
  • Sodium channel blockers (act on “0” in action potential)
  • 1a (mod): quinidine, procainamide - long QRS and long QT
  • 1b (weak): lidocaine, phenytoin - no ECG changes
  • 1c (strong): flecainide - long QRS but not long QT
  • Leads to slower depolarisation, slower conduction of action potential, and slower heart rate
139
Q

Class 2 antiarrhythmics

A
  • Beta blockers (act on “4” in action potential)

- e.g. propranolol, metoprolol

140
Q

Class 3 antiarrhythmics

A
  • K+ channel blockers (act on “3” in action potential)
  • e.g. amiodarone (also has class 1-4 activity), sotalol (also a non selective b-blocker)
  • Prolonged depolarisation and refractory period = longer QT interval on ECG
  • Leads to decr HR, but risk of torsades
141
Q

Class 4 antiarrhythmics

A
  • Ca2+ channel blockers (act on “2” in action potential)
  • e.g verapamil + diltiazem (heart), amlodipine (sm. muscle)
  • ECG: long PR
  • Dec rate through SA and AV node
  • Verapamil contraindicated in children
142
Q

Side effects of sotalol?

A
  • K channel blockers

- Bradycardia, lethargy, QT prolongation

143
Q

Side effects of amiodarone?

A
  • K channel blocker

- Photosensitivity, thyroid dysfunction, lungs, liver

144
Q

Side effects of flecainide?

A
  • Na channel blocker

- Tingling, constipation, blurred vision, broadens QRS

145
Q

Side effects of digoxin?

A
  • Contraindicated in WPW, propagates reentry tachycardia
  • Can cause hyperkalaemia
  • Monitor drug levels, adjust dose with amiodarone
146
Q

Most common cause of underlying heart disease in SVT?

A
  • The incidence of underlying congenital heart disease is up to 20%
  • Congenitally corrected transposition (L-TGA) and Ebstein’s anomaly most common
147
Q

Acute treatment of non-shocked:

  • SVT
  • VT
  • Atrial flutter or atrial tachycardia
  • Fascicular VT
A
  • SVT - vagal, adenosine
  • VT - amiodarone
  • Atrial flutter or tachycardia - amiodarone
  • Fascicular VT - verapamil
148
Q

What is the mechanism of nitric oxide?

A
  • Endothelial derived relaxing factor, causes vasodilation
  • It is produced in the endothelium of blood vessels and diffuses out of the cells
  • Enters vascular smooth muscle cells and activates guanylate cyclase which forms cyclic guanosine monophosphate (cGMP)
  • This leads to smooth muscle relaxation
149
Q

How do beta-blockers work

A
  • Can B1-receptor selective, or B1+B2
  • Prevent binding of adrenaline, decr number of calcium channels opening, decr intracellular calcium, leads to decreased HR and prolongation of action potential
  • Decr HR from SA node and decr conduction velocity through AV node - longer PR interval on ECG
  • Also reduce contractility by reducing intracellular Ca
  • Decr HR and decr contractility leads to dec O2 demand
  • Don’t use with CCB due to additive effect + AV block
150
Q

Most common CHD in Turners?

A
  • Bicuspid aortic valve (15%)
  • Aortic stenosis (10%)
  • Coarctation (10%)
151
Q

CHD in Klinefelter’s?

A
  • 50%

- ASD, PDA, mitral valve prolapse

152
Q

Most common CHD in 22q11?

A
  • ToF (35%)
  • Interrupted aortic arch (20%) - type B most common
  • Truncus arteriosus (10%)
  • Vascular anomalies (50%) - R sided arch, L SVC, vascular rings
153
Q

Discuss hypertrophic cardiomyopathy

A
  • Increased muscle bulk, esp septum and LV
  • Leads to stiff and bulky ventricle (can get S4 HS)
  • Reduced ventricular filling (diastole), therefore reduced output (SV) and diastolic heart failure
  • Can get obstruction of outflow tract during systole - crescendo-decrescendo murmur
  • Can cause arrhythmia and sudden death due to ischaemia
  • Can get SOB or syncope
  • Can be AD inherited, due to Friedrich Ataxia
  • Tx: beta blockers or CCB to reduce HR (digoxin contraindicated)
154
Q

CHD in Marfan’s?

A

Aortic root dilation, mitral valve prolapse

155
Q

CHARGE syndrome is associated with which CHD?

A

Conotruncal and arch abnormalities

156
Q

VACTERL is associated with which CHD?

A

ASD, VSD, ToF

157
Q

CHD seen in Holt Oram?

A
  • ASD, VSD
  • 1st degree heart block, can progress to complete heart block
  • AD, TBX5 mutation
  • Radial defects, varying severity
158
Q

Left atrial isomerism features

A
  • 2 left lungs, 2 left atria, polysplenia (small + non functional), central-transverse liver, interrupted IVC
  • 50% CHD - simple acyanotic and abnormal rhythms e.g. complete heart block
159
Q

Right atrial isomerism features

A
  • 2 right lungs, 2 right atria, asplenia, central-transverse liver
  • 90% CHD - cyanotic, complex and anomalous pulmonary venous return
160
Q

Sinus venosus ASD is associated with?

A

Partial anomalous pulmonary venous return

161
Q

D-transposition aorta location s L-transposition

A
  • D: Aorta attached to RV. Lies anteriorly and left of PA

- L: Aorta lies anteriorly and left of PA

162
Q

Causes of L to R shunts

A
  • VSD
  • PDA
  • ASD
  • Partial anomalous pulmonary venous drainage
163
Q

Apex of heart pointed down vs up on CXR?

A

Down = LV enlargement, Up = RV enlargement

164
Q

ToF vs transposition on CXR?

A
  • ToF = boot shaped, oligaemic lung fields due to pulm stenosis
  • Transposition = egg on a string,can have prominent vessels in lung fields
165
Q

Rib notching on CXR is seen in?

A

Coarctation of aorta, usually >10 yrs age, due to collateral vessels. Inferior aspect 3rd-8th ribs posteriorly.

166
Q

CXR and ECG in sick neonate with coarctation aorta?

A
  • CXR - cardiomegaly, LVH, pulmonary oedema

- ECG: may have RVH and RBBB, rather than LVH

167
Q

ECG and murmur in asymptomatic coarctation aorta?

A
  • ECG: normal or LVH
  • Murmur RUSE and LMSE, radiation to back (interscapular area). Ejection click due to bicuspid valve
  • CXR: rib notching or “3” sign
168
Q

Obstructed TAPVD on CXR?

A

Normal heart size with severe bilateral pulmonary oedema

169
Q

Cardiac abnormalities in Kawasaki Disease

A
  • Coronary artery aneurysms 25% at 4w if no IVIG -> 4% with single IVIG
  • Thrombosis, rupture, MI -> 1% if aneurysm not large
  • Myocarditis - common, transient
  • Mitral regurg - common 25%, mild-mod, resolves with follow up
  • Aortic root dilation 10% during acute phase of illness
  • KD shock syndrome, hypotension, requires inotrope and volume expanders
170
Q

Treatment of Kawasaki Disease

A
  • IVIG 2g/kg over 10-12 hrs, ASAP but up to 10 days. Up to 10-20% need 2nd dose IVIG +/- methylpred
  • High dose aspirin 30-50mg/kg/d until afeb 48-72 hrs, reduced to 3-5mg/kg/d (reduces thrombosis risk not aneurysm risk) until normal ECHO at 6w follow-up
  • Steroids if high risk
  • Large aneurysms need LMWH/warfarin
171
Q

Aschoff bodies are seen on the histology of which disease?

A

Rheumatic heart disease

172
Q

Pathogenesis in rheumatic fever?

A
  • M-protein on GAS is major virulence factor, similar to cells in body -> body attacks own cells - molecular mimicry, T2 hypersensitivity reaction
  • Antibodies bind to endothelial valve surface causing inflammation, infiltration, damage, granulomatous inflammation
  • Aschoff bodies
173
Q

What percentage of RHF develop RHD?

A
  • 35-65%
  • Esp those with severe carditis
  • AR less likely to disappear than MR
174
Q

Discuss the findings in severe MR?

A
  • Low volume pulse
  • Displaced apex
  • Cardiomegaly with LVH, LAH or dilation
  • Pan systolic murmur with diastolic rumble
175
Q

Discuss the findings in severe AR?

A
  • Collapsing pulse, wide pulse pressure
  • Displaced apex +/- heave
  • Diastolic murmur + systolic murmur +/- Austin Flint diastolic murmur
  • LVH
  • Cardiomegaly
176
Q

Treatment in rheumatic fever?

A
  • Arthritis: naproxen, safer than aspirin
  • Chorea: normally self resolves, otherwise carbamazepine, valproate
  • Carditis: bed rest until ESR <30, diuretic for failure, ACE inhibitor for severe failure, valve surgery
  • Penicillin prophylaxis: mild - min 10 yrs or until age 21, mod - until age 30, severe - until age 40
  • Benzathine penicillin I< every 21-28 days, 600,000 units if <30kg, 1.2mil units if >30kg
177
Q

Endothelial derived vasodilator?

A
  • Prostacyclin

- Also inhibits platelets activation

178
Q

Loud P2 indicates?

A

Pulmonary hypertension

179
Q

Definition of pulmonary hypertension?

A

Mean pulmonary artery pressure >25mmHg (normally 15) in the presence of equal distribution of blood flow to all segments of both lungs. >3 months of age

180
Q

Syndromes associated with pulmonary hypertension?

A
  • T21 - airway and cardiac disease
  • Noonans
  • DiGeorge - lung disease
  • Pierre Robin - airways disease
181
Q

Signs of pulmonary hypertension on exam?

A
  • Often normal exam
  • RV heave
  • Narrow split or single S2, loud S2
  • Systolic murmur of TR
  • Diastolic murmur of PR
  • Hepatomegaly
  • Peripheral oedema
182
Q

Treatment of pulmonary hypertension?

A
  • Nitric oxide - acute, short acting
  • Sildenafil - 1st line. Inhibits breakdown of cyclic GMP which increases endogenous nitric oxide leading to vasodilation
  • Bosantan - 2nd line - endothelin receptor antagonist
  • Illoprost - 3rd line - inhibits platelet aggregation, prostacyclin pathway
  • Last resort = atrial septostomy “pop off valve” to produce cyanosis in crisis but at least allows blood flow
  • Lung +/- heart transplant
183
Q

Discuss management of acute pulmonary hypertensive crisis

A
  • Rapid rise in PVR leads to acute RHF and inadequate cardiac output
  • Triggers: surgery, GA, acute lung disease, fever, hypovolaemia
  • Tx: oxygen, avoid hypercarbia (causes pulm vasoconstriction), correct metabolic acidosis, avoid hypovolaemia, nitric oxide, inotropes, ECMO
184
Q

Discuss Eisenmenger syndrome

A
  • When PVR > SVR
  • Acyanotic lesions (ASD, VSD, PDA) become cyanotic as shunt reverses
  • Complications: stroke, renal insuff, hypertrophic osteoarthropathy, polycythaemia, thrombocytopenia
185
Q

Drugs not to use in WPW

A

Digoxin

Calcium channel blockers - Verapamil

186
Q

LQTS 1-3 GENETIC INHERITANCE

A

LQTS1: loss of function mutation
KCNQ1 gene encodes the slowly activating delayed rectifier K+ channel, which conducts the IKs current.
EXERCISE

LQTS2: loss of function mutation
KCNH2 gene encodes the rapidly activating delayed rectifier K+ channel, which conducts the IKr current. Mutation results in reduced IKr activityprolongation of the repolarization phase
EMOTION

LQTS3: gain of function mutation
SCN5A gene encodes the Na+ channels. Mutation results in a small non-inactivating sodium current that remains active during the plateau phaseadditional depolarising current, prolonging repolarisation
SLEEP

187
Q

Catecholaminergic polymorphic VT due to mutation in .. gene

A

65% of cases (and majority paediatric patients) autosomal dominant mutation in the gene encoding cardiac ryanodine receptor (RyR2) which is involved in Ca2+ release important in ventricular depolarisation, and normally switches off Ca2+ release during diastole

• Gain of function mutation persistent Ca2+ leak during diastole. Substrate for delayed after depolarisations, particularly in setting of β-adrenergic stimulation during stress/exercise

ECG- PVCs with increasing exercise –> VT

Paeds (25 decks)

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