Cardiology Flashcards
What are the x3 shunts present in the antenatal circulation?
Ductus Venosus
Ductus Arteriosus
Foramen Ovale
What circulatory changes occur at birth?
1) Ductus Venosus closes as placenta removed
2) Left sided circulation pressure increases which closes the Ductus Ateriosus
3) LA pressure > RA pressure causes the foramen ovale to close
There is an increase in left sided circulation as increased pulmonary return and reduced IVC flow / placenta removed
Incidence of significant cardiac malformations in live births?
8 in 1000
Incidence of cardiac abnormalities in stillborns?
1 in 10 / 10%
Incidence of some cardiac abnormality in live births?
1-2%
What % of CHD is VSD?
30%
What % of CHD is PDA ?
12%
What % of CHD is ASD?
7%
What % of CHD is TOF?
5%
What % of CHD is TGA?
5%
What % of CHD is AVSD (complete)
2%
What % of CHD is pulmonary stenosis?
7%
What % of CHD is aortic stenosis?
5%
What % of CHD is coarctation of the aorta?
5%
List some causes of congenital heart disease?
Maternal factors:
- Rubella infection
- SLE
- DM
- Enterovirus in 3rd Trimester
- Coxsackie virus in 3rd Trimester
Drugs:
- Warfarin
- Alcohol
- Lithium
Genetic causes:
- Trisomy (13, 18, 21)
- Turner Syndrome (45XO)
- William’s Syndrome (7q11.23 microdeletion)
- Noonan Sx (PTPN 11 mutation)
- Chromosome 22q11.2 deletion
Left to Right shunts (breathless)
VSD
ASD
PDA
Right to Left shunts (blue)
TOF
TGA
Eisenmenger Sx
Common Mixing (blue and breathless)
Complete AVSD
Tricuspid atresia
Complex CHD
Outflow Obstruction (Well Child)
Aortic Stenosis
Pulmonary Stenosis
Adult type CoA
Outflow Obstruction (Sick/Collapsed Neonate)
Critical AS
HLHS
CoA
Total anomalous pulmonary venous connection
Interruption of the Aortic Arch
Incidence of Infective Endocarditis
1 in 1000
Increased risk with CHD, prosthetic material in the heart, long term central lines and immunosuppression
Most common organisms in Infective Endocarditis
Staph aureus
Coagulase Negative Staph (CoNs)
Strep viridans (alpha-haemolytic strep)
Common organisms causing Infective Endocarditis in diabetic and immunocompromised children
HACEK
- Haemophilus
- Actinobacillus
- Cardiobacterium
- Eikenella
- Kingella
The above are fastidious (difficult to culture)
Sequelae of emboli in infective endocarditis
Brain
- Strokes
- Intracranial abscess/infection
- Intracranial vasculitis and bleeds
Lung
- Septic pulmonary emboli +/- haemorrhage
Kidney
- Glomerulonephritis
Spleen
- Splenic infarct + splenomegaly
Gut
- Mesenteric infarct
List the diagnostic criteria for IE
Modified Duke Criteria (2 major, 1 major + 3 minor or 5 minor)
Major criteria:
- x2 positive blood cultures
- Mass/vegetation/paravalvular abscess/new valvular regurgitation/prosthetic valve dehiscence on Echo
Minor criteria:
- Predisposing factors (CHD, IVDU, tattoos)
- Fever >38
- Vascular phenomena (PE, arterial emboli, ICH, conjunctival haemorrhage, Janeway lesions)
- Immunologic phenomena (Roth spots, Osler nodes, Glomerulonephritis, Rf factor positive)
What are Roth spots
Also known as Litten spots
Seen in IE;
- white centered retinal haemorrhages
Criteria for prophylaxis against infective endocarditis?
Acquired valvular heart disease (stenosis or regurgitation)
Hypertrophic cardiomyopathy
Prev IE
Structural CHD (including surgically corrected or palliative conditions)
Valve replacements
3 stages of surgical correction for HLHS?
1) Norwood procedure within first week of life
2) Glenn procedure at 3-6 months
3) Fontan procedure at 2-3 years (one ventricle supports both the pulmonary and systemic circulation). IT IS A PALLIATIVE PROCEDURE.
Surgical management for TGA?
Typically have a balloon atrial septostomy for stabilisation
Followed by the arterial switch operation (this has replaced the mustard operation)
If a VSD is also present would undergo the Rastelli operation
What type of vasculitis is Kawasaki disease?
Medium vessel vasculitis
Predilection for coronary arteries
Management of PDA
Trial of paracetamol , ibuprofen or indomethacin (if no contraindications e.g. renal impairment, hepatic impairment)
Duct ligation
List some duct dependent lesions
TGA
HLHS
Pulmonary atresia
Tricuspid atresia
CoA
Pulmonary stenosis
What is the most common congenital heart defect?
Bicuspid Aortic Valve
Management of Paediatric SVT
1) Ice water to the face
2) Adenosine
3) Synchronised DC cardioversion (1J/kg for first shock followed by 2J/kg)
At what age do cyanotic spells usually develop in those with TOF?
4-6 months of age
Pathophysiology of hypertrophic cardiomyopathy (HCM)
Genetic predisposition (abnormal formation of sarcomeric proteins of the cardiac myocyte)
Hypertrophy reduces the volume of the LV cavity and thus the ability of the LV to fill in diastole.
Reduced LV filling = rising LA pressure, pulmonary oedema and congestive heart failure
x2 types of HCM
Obstructive (obstruction caused by the anterior leaflet of the mitral valve)
Non-obstructive (more common)
Pharmacological management of HCM
Beta blockers (slow HR and improve LV filling)
CCBs
Diuretics
ACEi (reduces afterload)
Surgical options for HCM
Implantable cardioverter defibrillator
LV myomectomy if significant obstruction
Biggest risk associated with HCM/HOCM?
High arrhythmia and SCD risk
What is the most common cause of acquired heart disease in children/adolescents?
Rheumatic fever
Aetiology of Rheumatic fever?
Immunologic reaction that is a delayed sequela of group A beta-haemolytic strep infection of the pharynx (Strep throat or scarlet fever)
Exact pathophysiology unclear, theories include:
- GAS produces enzymes e.g. streptolysin O which may be cytotoxic to cardiac cells
- Immune response fails to differentiate between epitopes of strep pathogen and host tissue
List the diagnostic criteria for Rheumatic Fever
Duckett-Jones / Modified Jones criteria (2 major or 1 major and 2 minor)
Major criteria:
- Migratory polyarthritis
- Carditis
- Subcutaneous nodules (extensor surfaces or scalp)
- Erythema marginatum (non pruritic, worse with warm water)
- Sydenham’s chorea
Minor criteria:
- Arthralgia
- Fever
- Elevated acute phase reactants (ESR, CRP)
- Prolonged PR interval
Recurrent RF can be diagnosed with 3 minor criteria and evidence of previous group A strep infection
In what % of cases is ASOT elevated in Rheumatic Fever?
80%
Management of Rheumatic Fever
Bed rest in the acute phase (1-6 weeks)
Pharmacological:
- Aspirin / Pred
- Penicillin (IM BenPen). Erythromycin if pen allergic.
- ACEi, Digoxin, diuretics to manage heart failure
- Diazepam / AEDs or IVIG for chorea
Surgical:
- Valvular repair or replacement (mitral valve)
What is key to think about in the long term management of Rheumatic Fever?
High risk of recurrence so may require penicillin prophylaxis (duration/frequency dependent on whether there is cardiac involvement)
Minimum is at least 5 years treatment
At what time period does Rheumatic fever occur following an URTI (strep throat or scarlet fever)
2-6 weeks
Which side of the heart is most commonly affected in IE?
Left
Unless IVDU then right sided more lesions more common
Mortality in IE
20% mortality rate!
Diagnostic Criteria for IE
Modified Duke’s criteria
Diagnostic criteria for Rheumatic Fever
Modified Jones’ / Duckett Jones criteria
Where exactly is the infection in IE?
Infection of the endothelium (endothelial surface of cardiac valves)
Why is CHD a risk factor for IE?
Turbulent blood flow
Most common cause of myocarditis in the Western world
Viral infections
Coxsackie = most common organism
Most common cause of myocarditis in children globally?
Chagas disease (Trypanosoma cruzi)
Management of Kawasaki disease
High dose aspirin and IVIG
What are the x2 genetic causes of long QT syndrome?
Romano-Ward syndrome
Jervell and Lang-Nielsen syndrome
Pathophysiology of long QT syndrome and risk of arrhythmias
Defective ion channels (Na/K/Ca) slows the flux of ions in stage 2/3 of the cardiac action potential leaving the myocardium to be depolarised for longer than it should be.
In this state there is a much higher risk of generating abnormal conduction pathways that degenerate into uncoordinated electrical activity, e.g. monomorphic VT / VF / Torsades de Pointes (polymorphic VT)
Causes of Long QT syndrome
Genetic:
- Romano-Ward syndrome (most common)
- Jervell and Lang-Nielsen syndrome
Acquired:
- Electrolyte imbalances (hypokalaemia, hypocalcaemia, hypomagnasaemia)
- Medications (antipsychotics, antibiotics, antimalarials)
- Cocaine
- HIV
- MI
- Hypothyroidism
Inheritance pattern of Romano-Ward syndrome
Autosomal dominant
Inheritance pattern of Jervell and Lang-Nielsen syndrome
Autosomal recessive
Which genetic long QT syndrome is associated with sensorineural hearing loss?
Jervell and Lang-Nielsen syndrome (affects K channels in the ear as well)
Medication of choice to manage long QT syndrome and risks associated with this
Beta blockers (propranolol or atenolol) as they reduce the risk of ectopic activity during prolonged repolarisation
Risk it can also further prolong the QT interval
Management of long QT syndrome
Non-pharmacological:
- Avoid stressful stimuli and heavy exercise
- Close control of electrolytes, particularly post-op
Pharmacological:
- Beta blockers
Surgical
- ICD
What is long QT syndrome?
A group of conditions causing abnormality of the repolarisation of ventricles (affects ion channels involved in stage 2/3 of the cardiac action potential)
Bazett’s formula for calculating QTc
QTc = QT / √ (RR)
Which is the most common genetic long QT syndrome?
Romano-Ward syndrome
Types of SVT
Atrial tachycardia
- Rare, usually only post-cardiac surgery
Nodal tachycardia (AVN/junctional/AVNRT)
- Abnormal re-entrant pathway within the AVN
AV re-entrant tachycardia (AVRT) (10-20% of SVTs)
- Accessory conduction pathway between atria and ventricles, e.g. WPW syndrome
What are the x2 types of WPW syndrome?
Orthodromic:
- Conduction flows normally from SAN->AVN-> Ventricle however accessory pathway allows retrograde conduction back up to atria
Antidromic:
- Normal conduction from SAN->AVN however accessory pathway then allows abnormal conduction through ventricles back up to AVN
ECG findings in WPW syndrome
Delta wave (slur of QRS due to accessory pathway)
Narrow complex tachycardia
Short PR (due to pre-excitation of ventricle due to accessory pathway)
Normal/narrow QRS in Orthodromic
Broad QRS in Antidromic
Loud pansystolic murmur lower left sternal edge
VSD
Rare but another cause is Tricuspid regurgitation (Ebstein anomaly)
1) ESM at right upper sternal edge which radiates to the carotids
2) What other signs may you find
1) Aortic Stenosis
2) Suprasternal notch or carotid thrill
Systolic murmur at left upper sternal edge with a split S2 (does not vary with respiration)
ASD
ESM loudest at the left upper sternal edge radiating to the back
Pulmonary Stenosis
What defects may you find a precordial thrill in?
VSD
Pulmonary stenosis
PSM at the apex
Mitral regurgitation
When would an ejection click be heard?
Valvular AS or PS
NO ejection click if sub or supra-valvular
Most common form of SVT in children >8 years old
AVNRT
Most common form of SVT in children <8 years old
AVRT (e.g. WPW Sx)
When would you treat aortic stenosis?
Gradient across the valve >60mmHg
Treatment usually involves balloon valvuloplasty or surgical valvuloplasty. Avoid valve replacement in children.
Types of ASD
Ostium secundum (most common)
Ostium primum / partial AVSD
Sinus venosus
Continuous murmur in infraclavicular region with collapsing pulse
Persistent arterial duct
Continuous murmur in infraclavicular region with lateral thoracotomy
BT shunt
Diastolic murmur at left sternal edge/apex
Aortic regurgitation
ESM at upper left sternal edge + median sternotomy scar
TOF repaired
Long harsh systolic murmur and cyanosis
TOF
Where is the defect in Secundum ASD
Defect in the centre of the atrial septum involving the fossa ovalis
Where is the defect in Primum ASD
Partial AVSD - defect in the lower atrial septum involving the left AV valve which has 3 leaflets and tends to leak
Mx of TOF
Elective repair 6-9 mths old
May have BT shunt as neonate if severely cyanosed
Boot shaped heart on XR
TOF
Pulmonary atresia
Egg on side on XR
TGA
Snowman in a snowstorm or cottage loaf appearance on XR
Total anomalous pulmonary venous connection
When to repair an ASD?
Pulmonary-to-systemic-flow ratio > 2:1
Most common cause of cyanotic heart disease in the neonatal period?
TGA
Systolic murmur in the second left intercostal space and prominent precordial motion (tripple ripple) with a late second systolic impulse
HOCM
Features of Still’s / Innocent mumur
Soft
Systolic
Short
Sternal edge (loudest at)
Supine position (heard in)
Symptomless
What does a prominent left precordium suggest?
The right ventricle was dilated during childhood, e.g. due to pulmonary hypertension
Incidence of PDA in pre-term babies?
20-60%
The ductus may also remain open for many weeks
In which condition would you see a reduction in the intensity of the murmur as cyanosis worsens?
TOF - this is because during a tet spell there is increased right sided outflow obstruction / reduced pulmonary blood flow
Pathophysiology of a Tet spell
Increase in right sided pressure which causes a right to left shunt and increased cyanosis due to more deoxygenated blood entering the systemic circulation
Can be caused by:
- Reduced O2 Sats (pulmonary hypoxic vasoconstriction) e.g due to crying
- Decrease in systemic vascular resistance (playing, hypovolaemia)
- Tachycardia (distress)
This deoxygenation causes:
- Hyperpnea due to stimulation of resp centre (increased adrenergic tone and catecholamines)
- Catecholamines cause increased contractility which increases outflow obstruction
Management of a Tet spell
Aim to increase systemic pressure / left sided pressure and reduce pulmonary pressure
Increase systemic pressure:
- Squat
- Raise legs / bring knees to chest
- IVI
- Vasopressors
Reduce pulmonary pressure
- O2 to reduce hypoxic vasoconstriction
Reduce RR
- Morphine
