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
2
Q
Interrupted aortic arch, cleft palate and hypocalcaemia
A
22q11.2 deletion
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
4
Q
Causes of prolonged QTc?
A
Jervell-Lange-Nielsen syndrome CNS/Head injury Hypokalaemia Erythromycin Hypocalcaemia Hypomagnesemia Adrenal insufficiency Hypothermia Quinidine Phaeochromocytoma
5
Q
Examples of calcium channel blockers
A
Amlodipine, nifidepine, verapamil
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
7
Q
What ECG features would you find in Ebstein’s Anomaly?
A
RBBB, RAH, 1st degree AV block, delta wave (WPW)
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
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
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.
11
Q
Most common cardiac anomalies in William’s syndrome?
A
Supravalvular aortic stenosis (most common), peripheral pulmonary stenosis, and supravalvular pulmonary artery stenosis
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
13
Q
Qp:Qs ratio
A
(PV - PA)
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)
15
Q
What causes wide splitting of S2?
A
ASD, PS (pressure overload), Ebstein anomaly, TAPVR, RBBB (electrical delay), MR (early aortic closure)
16
Q
What causes an accentuated pulmonary component of S2 with narrow splitting?
A
Pulmonary hypertension
17
Q
What causes a single second heart sound?
A
- Pulmonary or aortic atresia or severe stenosis
- Truncus arteriosus
- Transposition of the great arteries
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)
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
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
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
22
Q
Why does primum ASD cause a LAD?
A
Because the AV node is displaced posteriorly
23
Q
What is the mean pulmonary artery wedge pressure an indirect measure of?
A
The mean left atrial pressure
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.
25
How do you calculate stroke volume?
EDV - ESV
26
How do you calculate ejection fraction?
EDV - ESV
----------------
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)
27
What factors affect ventricular preload?
- 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
28
What is the Frank-Starling law?
- 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
29
What is ventricular afterload?
- 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
30
What is the effect of afterload on stroke volume?
- Inc afterload causes decr stroke volume -> inc preload
| - Decr afterload causes incr stroke volume -> decr preload
31
What is the main contributor to the oedema found in congestive heart failure?
Sodium retention via the renin-angiotensin-aldosterone pathway (due to poor cardiac output leading to reduced perfusion of juxtaglomerular apparatus)
32
What ECG change would you see in a primum atrial defect?
- 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.
33
What causes an S3 heart sound?
- 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)
34
What causes an S4 heart sound?
- "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
35
Causes of myocarditis?
- Infection: adenovirus, enterovirus, parvovirus, Chagas, zika, other viruses, mycoplasma
- Meds: doxorubicin, antibiotics, tricyclic antidepressants, phenytoin
- Autoimmune: coeliac, lupus, Kawasaki, Crohns, sarcoid
36
Which drugs can prolong the QTc?
Antiarrhythmics e.g. amiodarone, TCAs, antipsychotics (haloperidol, quetiapine), anti-infectives (clarithromycin, fluconazole, erythromycin).
37
Paradoxical splitting of S2 in expiration occurs in?
Severe aortic stenosis
38
Discuss coronary artery fistulas
- 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.
39
Discuss the differences in KCNQ1, KCNH2 and SCN5A gene mutations
- 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
40
Differential cardiac diagnoses for infants that are critically ill
in the first 24 hours include?
- Valve problems (e.g. Ebstein's, absent pulmonary valve syndrome)
- Obstructed TAPVD
- ‘Early’ duct dependent circulation
41
What are causes of significant cardiomegaly at birth?
- Ebstein's anomaly - wall to wall heart
- Fetal cardiomyopathy
- Pompe disease (GSD type 2)
- AVM
42
Infant with profound cyanosis without respiratory distress... suspect?
Transposition of the great arteries, sats usually 50-70%
43
Discuss Brugada syndrome
- 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
44
ECG findings in HOCM?
Voltage criteria for LVH with associated ST segment repolarisation abnormalities are classical ECG findings in hypertrophic cardiomyopathy
45
A long systolic murmur at the left sternal edge?
Could represent a VSD, TOF, Still’s, or TR
46
Management of VT with pulse and:
- Shocked
- Not shocked?
- 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
47
Treatment of bradycardia in shocked child:
- Due to vagal overactivity
- Not due to vagal overactivity
- Vagal overactivity: atropine 20mcg/kg
| - Not due to vagal overactivity: adrenaline 10mcg/kg
48
Management of SVT:
- With shock
- Without shock
- 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
49
Endocardial fibroelastosis is associated with which infection in pregnancy, and what are the features?
- Mumps
- Aortic stenosis, hypoplastic left heart and aortic coarctation
- Echocardiogram shows opaque white fibroelastic thickening of the endocardial surface of the heart.
50
What is the mechanism of action of digoxin?
- Digoxin, a Na/K/ATPase pump inhibitor, depresses the SA and AV nodes, prolongs refractiveness and slows conduction
- Side effects of overdose: arrhythmia, hyperkalaemia
51
Medication used in long QT syndrome?
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.
52
Medication used in cardiomyopathy to prevent arrhythmias?
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).
53
Medication used in atrial flutter?
Sotalol
54
Medication used in WPW?
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.
55
How can you calculate the cardiac output?
CO = oxygen consumption (ml/min) / arteriovenous oxygen difference
CO = VO2/(A-V)
56
RsR in V1 vs RsR in V6
- V1 = partial RBBB
| - V6 = partial LBBB (rarely seen in paeds)
57
Partial vs complete bundle branch block
If QRS is prolonged (>0.12) then complete BBB. If QRS is normal then partial RBBB
58
What are the findings in a Still's murmur?
- 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
59
Tall R wave V1 with deep S wave in V6 indicates?
- 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
60
Upright T waves in V1 between day 4 age and 4yo indicates?
- Pathological RVH
- Allowed to be upright until day 4
- Severe RVH the T wave goes down again due to strain
61
Large P waves indicate?
- If tall = p pulmonale = RAH, >3mm tall
| - If bifid or wave (V1) = p mitrale = LAH, >2.5 sq wide = >0.10 sec
62
Causes of RVH on ECG?
- ASD
- Large VSD with pulmonary hypertension
- ToF
- Pulmonary stenosis
- TAPVR
63
What are the findings of LVH on ECG?
- 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
64
Causes of LVH on ECG?
- Aortic stenosis
- Systemic hypertension
- Large VSD
- PDA
- Cardiomyopathy
65
Familial causes of prolonged QT
- Romano Ward
- Jervell and Lange Nielsen syndromes
(others = electrolytes, drugs, metabolic)
66
TAPVD on ECG?
RAD, RVH, RAH
| Cyanotic child
67
Causes of RAH on ECG?
- ASD
- Tricuspid stenosis or atresia
- Tricuspid regurg
68
Causes of LAH on ECG?
- Mitral stenosis or atresia
- Mitral regurg
- L-R shunt with large VSD causing increased return to LA
- PDA (inc R volume loading)
69
ECG findings of incomplete AV canal defect or ostium primum defect?
- LAD (due to shift of SA node)
- RVH +/- RAH
- Incomplete RBBB
70
When are Q waves on ECG normal?
Normal if narrow and in inferior or lateral leads
71
Causes of abnormal ST segment?
> 1mm in limb leads, >2mm in V2-V4
| Pericarditis, myocarditis, MI, electrolyte abnormalities
72
Which CHD preset as critically ill in the first 24 hours?
- 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
73
Discuss the findings in Ebstein's
- 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
74
Discuss the findings in TAPVD
- 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
75
Supracardiac TAPVD on CXR
- Snowman sign
| - Widened mediastinum, flattened diaphragm, increased lung vascularity
76
In which type of TAPVD does obstruction most commonly occur?
Infracardiac (PV return to liver or IVC)
77
Which CHD present within the first 24 hrs with:
- A murmur
- Cyanosis
- 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
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
- 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
Duct-dependent cyanotic heart disease:
- Oligaemic lung fields
- Mildly plethoric lung fields
- Congestion
- Massive cardiomegaly
- Oligaemic lung fields - pulm atresia or stenosis
- Mildly plethoric lung fields - TGA
- Congestion - TAPVD with obstruction + pulm oedema
- Massive cardiomegaly - Ebstein's
80
CXR findings in TGA
- Narrow mediastinum as aorta and PA are orientated ant-posteriorly (aorta = ant)
- Egg on a string
- Mildly plethoric lung fields
81
What is levo-TGA
- 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
Which CHD present between 2-6 weeks?
- 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
CXR findings in partial anomalous pulmonary venous drainage?
Scimitar sign, where right pulmonary veins join into IVC junction
84
Findings in coarctation?
- Murmur heard posteriorly between scapula
- Diminished femoral pulses
- Hypertension
- Associated with bicuspid aortic valve
85
Discuss venous hum murmur
- 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
Indications for cardiac catheterisation?
- Haemodynamics - flow, pressure, shunting, resistance, primary pulmonary hypertension
- Angiography - anatomy, can see extra-cardiac (missed on ECHO)
- Interventional e.g. balloon septostomy
87
Normal cardiac catheterisation data?
- 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
Triad of symptoms in aortic stenosis
- Breathlessness (restricted CO)
- Syncope
- Chest pain (lack of coronary blood flow)
89
Risks of cardiac catheterisation
- Common - fever, haematoma at groin, transient vessel occlusion, transient arrhythmia
- Uncommon (<1%) - stroke, seizure, allergic reaction, cardiac perforation
- Mortality <1%
- Radiation exposure
90
Findings of RVH on ECG
- 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
What is the significance of a Q wave in V1?
- Pathological (except occasional newborns)
| - L-TGA, single ventricle, severe RVH or anterior MI (deep and wide)
92
Biventricular hypertrophy on ECG
- Large R and S in V3
| - Make sure leads not at half gain
93
AVSD on ECG
- LAD or superior axis
- LAH and RAH
- LVH and RVH
(note: truncus will have BVH but normal axis)
94
ToF ECG findings pre and post op
- RAD, rsR pattern, RVH (tall R V1, deep S V6)
| - Post-op: RBBB
95
ECG in TGA
- Early newborn - normal ECG
| - Later - RAD, RVH
96
ECG in Ebstein's
- RAH, RAD
- No/small RV forces – commonly will have RBBB
- Pre-excitation - delta waves/WPW
- Absent “Q” waves in V6
- Risk of SVT
97
ECG in tricuspid atresia
- LAD, low right atrial axis
- Can have LAH, RAH, or combined
- No RV forces - lack of R wave in V1
98
ECG in coarctation
- 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
Pulmonary atresia with intact septum on ECG
- RAD
- RAH
- Loss of right ventricular predominance (small R wave V1) as RV not formed
100
Significance of a negative (upside down) p wave in lead I?
- Leads reversed or situs inversus, or ectopic atrial tachycardia
- Dextrocardia will have lack of R wave progression
101
Significance of ALCAPA
- 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
Hypoplatic L heart on ECG
- RAD, RVH
| - Lack of LV forces (no R wave in V5-V6)
103
Truncus arteriosus on ECG
- Normal axis
| - Biventricular hypertrophy
104
TAPVD on ECG
- RAH and RVH
| - RAD
105
Dextrocardia on ECG
- 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
How do you calculate PVR and SVR?
```
PVR = mean PAp - mean LAp / Qp
SVR = mean Aop - mean RAp / Qs
```
107
What are the risks post AV dilatation?
- 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
Why do we close ASDs in childhood?
- 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
What is the risk of a perimembranous VSD?
Lies close to aortic valve, risk of aortic regurgitation
110
Cardiac issues in Williams?
Supravalvular aortic stenosis and supravalvular pulmonary stenosis
111
Cardiac issues in Noonans?
Pulmonary stenosis
112
Types of SVT
- Accessory pathway (reentry tachycardia, most common cause SVT in paeds)
- AV nodal reentry
- Ectopic atrial tachycardia (from ectopic focus)
- Atrial flutter
- Atrial fibrillation
113
Discuss accessory pathway tachycardia
- 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
Discuss orthodromic AVRT
- 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
Discuss antidromic AVRT
- 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
Discuss Wolff Parkinson White
- 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
What is AV nodal reentry tachycardia?
- 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
Discuss ectopic atrial tachycardia
- 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
Discuss atrial flutter
- 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
Treatment of atrial flutter?
- Medical cardioversion: amiodarone or sotalol
| - Rate control: digoxin or B-blocker
121
Treatment of tahcyardia with shock?
Cardioversion - shock
| Doesn't matter if narrow or broad, irregular or regular
122
Discuss ventricular tachycardia
- 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
123
Discuss fasicular VT
- 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)
124
Why is verapamil usually contraindicated in children?
- Calcium channel blocker
| - Causes vasodilation leading to low output and cardiac arrest
125
Most common infectious causes of myocarditis?
- Coxsackie B (North America) + other viral
- Chagas (protozoa, South America) - see amastigote in heart muscle cells
- Lyme disease
126
Non infective causes of myocarditis?
- SLE
- Polymyositis
- Drug-induced - hypersensitivity reaction - eosinophils
- Giant cell arteritis - macrophages
127
Symptoms of myocarditis?
- Positional chest pain
- Arrhythmia - inflammation of pacemaker cells
- Fatigue, fever, SOB
- Can develop heart failure and oedema
128
Investigations in myocarditis?
- Raised CK and troponin
- ECG: sinus tachycardia, T wave inversions, saddle ST elevation
- CXR: cardiomegaly
- ECHO: inflammation of myocardium
129
Causes of pericarditis?
- Idiopathic
- Viral e.g. coxsackie B
- Uremic pericarditis
- Dressler syndrome (post MI)
- RA, SLE, scleroderma
- Radiation
- Meds e.g. penicillin, anticonvulsants
130
Pathogenesis of pericarditis
- 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
131
Symptoms/signs of pericarditis
- 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)
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Most common causes of infective endocarditis?
- 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
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Signs, symptoms of infective endocarditis
- Fever
- New murmur
- Septic emboli - splinter haemorrhage, roth spots, janeway lesions, osler's nodes, GN
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Discuss catecholaminergic VT
- 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
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Discuss long QT syndrome
- 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
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1st degree heart block
- PR prolongation with 1:1 AV conduction
- Secondary to ASD, rheumatic fever
- Rarely progresses to higher degree heart block
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2nd degree heart block
- 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
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3rd degree heart block
- 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
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Class I antiarrhythmics
- 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
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Class 2 antiarrhythmics
- Beta blockers (act on "4" in action potential)
| - e.g. propranolol, metoprolol
141
Class 3 antiarrhythmics
- 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
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Class 4 antiarrhythmics
- 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
143
Side effects of sotalol?
- K channel blockers
| - Bradycardia, lethargy, QT prolongation
144
Side effects of amiodarone?
- K channel blocker
| - Photosensitivity, thyroid dysfunction, lungs, liver
145
Side effects of flecainide?
- Na channel blocker
| - Tingling, constipation, blurred vision, broadens QRS
146
Side effects of digoxin?
- Contraindicated in WPW, propagates reentry tachycardia
- Can cause hyperkalaemia
- Monitor drug levels, adjust dose with amiodarone
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Most common cause of underlying heart disease in SVT?
- The incidence of underlying congenital heart disease is up to 20%
- Congenitally corrected transposition (L-TGA) and Ebstein's anomaly most common
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Acute treatment of non-shocked:
- SVT
- VT
- Atrial flutter or atrial tachycardia
- Fascicular VT
- SVT - vagal, adenosine
- VT - amiodarone
- Atrial flutter or tachycardia - amiodarone
- Fascicular VT - verapamil
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What is the mechanism of nitric oxide?
- 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
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How do beta-blockers work
- 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
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Most common CHD in Turners?
- Bicuspid aortic valve (15%)
- Aortic stenosis (10%)
- Coarctation (10%)
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CHD in Klinefelter's?
- 50%
| - ASD, PDA, mitral valve prolapse
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Most common CHD in 22q11?
- ToF (35%)
- Interrupted aortic arch (20%) - type B most common
- Truncus arteriosus (10%)
- Vascular anomalies (50%) - R sided arch, L SVC, vascular rings
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Discuss hypertrophic cardiomyopathy
- 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)
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CHD in Marfan's?
Aortic root dilation, mitral valve prolapse
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CHARGE syndrome is associated with which CHD?
Conotruncal and arch abnormalities
157
VACTERL is associated with which CHD?
ASD, VSD, ToF
158
CHD seen in Holt Oram?
- ASD, VSD
- 1st degree heart block, can progress to complete heart block
- AD, TBX5 mutation
- Radial defects, varying severity
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Left atrial isomerism features
- 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
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Right atrial isomerism features
- 2 right lungs, 2 right atria, asplenia, central-transverse liver
- 90% CHD - cyanotic, complex and anomalous pulmonary venous return
161
Sinus venosus ASD is associated with?
Partial anomalous pulmonary venous return
162
D-transposition aorta location s L-transposition
- D: Aorta attached to RV. Lies anteriorly and left of PA
| - L: Aorta lies anteriorly and left of PA
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Causes of L to R shunts
- VSD
- PDA
- ASD
- Partial anomalous pulmonary venous drainage
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Apex of heart pointed down vs up on CXR?
Down = LV enlargement, Up = RV enlargement
165
ToF vs transposition on CXR?
- ToF = boot shaped, oligaemic lung fields due to pulm stenosis
- Transposition = egg on a string,can have prominent vessels in lung fields
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Rib notching on CXR is seen in?
Coarctation of aorta, usually >10 yrs age, due to collateral vessels. Inferior aspect 3rd-8th ribs posteriorly.
167
CXR and ECG in sick neonate with coarctation aorta?
- CXR - cardiomegaly, LVH, pulmonary oedema
| - ECG: may have RVH and RBBB, rather than LVH
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ECG and murmur in asymptomatic coarctation aorta?
- 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
169
Obstructed TAPVD on CXR?
Normal heart size with severe bilateral pulmonary oedema
170
Cardiac abnormalities in Kawasaki Disease
- 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
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Treatment of Kawasaki Disease
- 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
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Aschoff bodies are seen on the histology of which disease?
Rheumatic heart disease
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Pathogenesis in rheumatic fever?
- 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
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What percentage of RHF develop RHD?
- 35-65%
- Esp those with severe carditis
- AR less likely to disappear than MR
175
Discuss the findings in severe MR?
- Low volume pulse
- Displaced apex
- Cardiomegaly with LVH, LAH or dilation
- Pan systolic murmur with diastolic rumble
176
Discuss the findings in severe AR?
- Collapsing pulse, wide pulse pressure
- Displaced apex +/- heave
- Diastolic murmur + systolic murmur +/- Austin Flint diastolic murmur
- LVH
- Cardiomegaly
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Treatment in rheumatic fever?
- 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
178
Endothelial derived vasodilator?
- Prostacyclin
| - Also inhibits platelets activation
179
Loud P2 indicates?
Pulmonary hypertension
180
Definition of pulmonary hypertension?
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
181
Syndromes associated with pulmonary hypertension?
- T21 - airway and cardiac disease
- Noonans
- DiGeorge - lung disease
- Pierre Robin - airways disease
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Signs of pulmonary hypertension on exam?
- Often normal exam
- RV heave
- Narrow split or single S2, loud S2
- Systolic murmur of TR
- Diastolic murmur of PR
- Hepatomegaly
- Peripheral oedema
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Treatment of pulmonary hypertension?
- 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
184
Discuss management of acute pulmonary hypertensive crisis
- 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
185
Discuss Eisenmenger syndrome
- When PVR > SVR
- Acyanotic lesions (ASD, VSD, PDA) become cyanotic as shunt reverses
- Complications: stroke, renal insuff, hypertrophic osteoarthropathy, polycythaemia, thrombocytopenia
