Cardiology Flashcards
Neonatal physiology - direction shunt - pulmonary resistance and blood flow - ventricles work
- R to L shunting at atrial level (PFO) and arterial level (ductus arteriosus)
- High pulmonary vascular resistance -> Little pulmonary blood flow
- Ventricles work in parallel
What cardiac problems can cause hydrops foetal or fetal loss inutero?
- Valve regurgitation (especially TR, AVSD, truncus arteriosus)
- Arrhythmia -> slow (complete heart block) -> fast (atrial arrhythmias)
Changes in physiology during transition from fetal circulation to neonatal circulation (post birth)
- Pulmonary vasc resistance falls
- Ductus venosus and ductus arteriosus close
- R to L shunting through foramen ovale CEASES Timing of these determines timing of presentation of congenital heart defects
What cardiac problems cause critical illness within first 24 hrs and how do they present?
- Valvular regurgitation (Ebstein’s anomale with TR and enlarged R atrium), Pulmonary atresia
- Obstructed TAPVD
- Early duct dependent presentation Present with respiratory distress
Ebstein’s anomaly
Cardiomegaly, massive (wall to wall) on CXR
Presents w resp distress in first 24 hrs
Secondary pulmonary hypoplasia due to compression of lungs by heart
TAPVD = Total anomalous pulmonary venous drainage
Types & presentation
Mx
Rare form of congenital heart disease where all four pulmonary veins drain to the systemic venous circulation
→ Supracardiac (most common) drain into SVC, later presentation of mild cyanosis -> CCF later down the track. CXR = snowman sign
→ Cardiac: drain into RA
→ Infracardiac drain into IVC, present as severe cyanosis and heart failure/shock in first 24 hrs of life if obstructed (infra cardiac drainage into IVC). CXR - white out or diffuse pulm congestion/plethora
Mx
- I&V
- Sedate
- Inotropes
- mx PPHN
- PGE may help w systemic perfusion but can WORSEN PULM BLOOD BFLOW
Murmurs presenting in first 24 hrs of life
Pulmonary or aortic stenosis
Mitral or tricuspid regurg
*Not ASD or VSD (can’t hear them at this stage, wait until pulm pressures fall ~2-6wks)
*TGA and hypoplastic L heart - single S2 but murmur may be absent early on
Duct dependent lesions when do these usually present?
24hrs to 2 weeks
1. Dependent on PDA for pulmonary blood flow
- Present w severe cyanosis when duct closes
- Critical pulmonary stenosis
- Pulmonary atresia
- Single ventricle with PS or PA
2. Dependent on PDA for systemic blood flow
- Present w low cardiac output (shock) when duct closes
- Critical AS
- Critical coarctation
- Hypoplastic left heart syndrome (HLHS)
3. Dependent on PDA for mixing
- P/w cyanosis when duct closes
- Transposition of great arteries
Ix for cyanotic neonate when ?TGA vs respiratory condition
CXR
ECG
Hyperoxia test (put them in high O2 conditions and see if they oxygenate
- If you can improve o2 sats/cyanosis resolves, likely a resp condition)
+/- Echo
Congestion on CXR in first 2 weeks of life - ?differential
TAPVD w obstruction
Mildly plethoric lung fields / narrow mediastinum (boot shaped heart) on CXR in first 2 weeks of life - ?differential
TGA
Oligaemic lung fields on CXR in first 2 weeks of life
?differential
Pulm stenosis
Pulmonary atresia etc
TGA
P/w cyanosis/hypoxaemia/tachypnoea within first day of life, progressively more severe as duct loses
- Single loud S2
- Murmur may be absent in first few days to weeks
- Progression to CCF over time if not treated
- M>F
- CXR: egg on a string
- ECG: RAD, RVH
Tx
- Prostaglandin/’prostin’ (keeps duct open)
+/- balloon septostomy (catheter through groin, blow up balloon and rip a hole in atrial septum) to aid mixing
- Arterial switch operation when a few days open after have dropped resistance a bit
Pulmonary atresia
Pulmonary valve is ‘blocked’
Presents w cyanosis (but often picked up antenatally)
ECG - tall p waves
Tx
- Prostaglandin to keep duct open
- Is there a coronary fistulae? determines whether or not you can open the valve (RVOT opening or duct stent)
Conditions that present at 2-6 weeks of life
What is this due to (physiology) how do they present?
Due to decreasing pulmonary vascular resistance
Present with congestive heart failure
- VSD w coartaction earliest
- Large VSD, PSD, AVSD, Truncus arteriosus, TOF with pulmonary atresia
- Other complex (single ventricle with no PS)
Sx of congestive heart failure in baby
Tachypnoea
Poor feeding
Tachycardia
Diaphoresis with feeds
Poor weight gain
Hepatomegaly
Truncus arteriosus
- Large vsd
- Arterial trunk that originates from both ventricles of the heart that later divides into the aorta and the pulmonary trunk
Sx are due to EXCESSIVE pulmonary blood flow
Present - 2-6 weeks of life when pulm vasc resistance drops and pulm blood flow increases with pulmonary over-circulation and signs of CCF: mild cyanosis, tachypnoea, tachycardia, resp distress, hepatomegaly
Signs: ejection click and systolic murmur, single loud second heart sound, and a diastolic murmur if truncal valve regurgitation is present (50% of pts, worsens sx). Bounding peripheral pulses from excess runoff into pulm arteries.
CXR - pulmonary plethora, cardiomegaly
ECG - RVH/LVH
Echo - can see large VSD and common trunk
Red flag features on examination of a child with a murmur
- Loud murmur
- Loud second heart sound
- Abnormal brachial and/or femoral pulses
Signs of CCF:
- Tachypnoea
- Poor feeding
- Tachycardia
- Diaphoresis with feeds
- Poor weight gain
- Hepatomegaly
ASD murmur features
Presents 2-6 weeks
Hyperdynamic precordium
Fixed split S2
Ejection systolic flow murmur at USB
+/- diastolic rumbling murmur at LLSB
Coarctation murmur and exam features
Short systolic murmur at LLSB
+/- systolic ejection click if bicuspid aortic valve
Murmur heard posteriorly
Diminished femoral pulses
Radio-femoral delay
HTN upper arms relative to lower limbs
Over time - cyanosis, tachypnoea, signs of HF
Characteristics of innocent murmurs in older children
Healthy child (no exercise intolerance, no resp infections, no family hx)
No signs of heart failure or cyanosis
Normal precordium (not hyperdynamic, no thrills or heaves)
- Murmur intensity varies with posture, incr w fever*
- Normal second heart sound (physiological splitting of S2 varying w respiration)*
- Comes and goes/intermittent*
Pressure overload vs volume overload in VSD vs ASD
- VSD causes pressure overload → Can lead to pulmonary vascular disease
- ASD causes volume overload → Does not lead to pulmonary vascular disease.
VSD murmur
Pansystolic harsh/blowing murmur at LLSB + palpable thrill +/- apical diastolic rumble
- Louder murmurs more likely to be ‘restrictive’ ie causing pressure overload, risk of pulmonary vascular disease if not managed early
Rheumatic heart disease
- What pathology does it cause in the heart
- Ix
- Pancarditis (pericardium, myocardium, endocardium affected)
- Usually mitral and/or aortic regurg
- Associated valve thickening and deformity
- Conduction abnormalities → May present with heart block
- Need ECG and echo for evidence of carditis (may be subclinical)
Causes of cardiomyopathy in a structurally normal heart
Myocarditis
Familial dilated cardiomyopathy
Tachycardia induced
Muscular dystrophies
Mitochondrial
Metabolic
Treatment of heart failure
Diuretics
ACEi
Spironolactone
Beta blockage (carvedilol)
IV Inotropes particularly dobutamine, milrinone Levosimendan (Ca sensitising agent)
syndromes assoc w CHD
De George syndrome (22q11)
- p/w w interrupted aortic arch, tet fallot, RAA, truncus
Turners syndrome
- coarctation, bicuspid aortic valve, aortopathy
T21
- ASD, VSD, AVSD, ToF, PDA
Williams Syndrome (supravalvular AS, peripheral PS)
VACTERL - VSD
CHARGE syndrome
Marfans (aortopathy)
Simplified bernoulli equation
Change in pressure = 4 x (distal velocity)^2
Fractional shortening What is it and what is normal value?
1D assessment of function on echo
Should be around about 30%
Ejection fractioning on echo
what is it
how do you calculate it
What is normal value?
VEntricular volumes at end of diastole and systole
EF = (EDV-ESV)/EDV
Should be around 60%
Indications for catheterisation
Hemodynamics
- shunts
- pulmonary vasc resistance/pressure
Angiography
- Great for vascular information
Intervention
- may need diagnostic cath before cardiac surgery
- stents
- valves
- creat/dilate holes
- close holes/block vessels
- balloon angioplasty or valvuloplasty
definition of pulmonary HTN (mmhg)
high BP in pulmonary arteries
pulmonary arterial pressure:
- mild > 25mm Hg
- mod >35
- severe >45
normal values sp02 in heart chambers
SVC/IVC, RA, RV, pa - 70%
pulm veins, la, lv, aorta - 95%
Presentation of left to right shunt
Pink patient with EXTRA pulmonary flow (‘heart failure’)
- breathless, soggy/plethoric CXR
Presentation of right to left shunt
Blue/cyanosed patient with REDUCED pulmonary flow (normal CO around body but LESS around lungs)
Blood from lungs mixes with that from body and results in blood that has reduced oxygenation
Cardiac embryology
Day
- 19: vasculogenesis in cardiac region
- 21: primitive heart tube formed
- 22: heart beats
- 28: folding of heart completed
- 56: outflow tracts and ventricles separated
- 63: semilunar valves complete
Haemodynamics of heart
- Normal pressure measurement in each chamber and temporal relation of ECG to mechanical events RA pressure RV
- peak systolic
- end diastolic Pulm artery
- mean pressure
- peak systolic
- end diastolic LA mean pressure LV
- peak systolic
- end diastolic Aorta mean pressure
RA pressure 2-8 (70ms after onset of P wave)
RV peak systolic 17-32
RV end diastolic 2-8 (RV contraction is 65ms after q wave)
Pulm artery
- mean pressure 9-19
- peak systolic 17-32
- end diastolic 4-13 (RV ejection into PA is 80ms after Q wave)
LA mean pressure 2-12 (LA contract is 85ms after P wave onset)
LV peak systolic 90-140
LV end diastolic 5-12 (LV ejection is 115ms after LV ejection)
Aorta mean pressure 70-105
IsoVOLUmetric contraction
Pressure in ventricles increasing but aortic valve still closed (VOLUME CONSTANT BUT PRESSURE INCR)
When pressure ventricle > aortic pressure, valve opens -> EJECTION PHASE (LV pressure increases a bit longer whilst volume decr in chamber until aortic pressure > LV pressure, then aortic valve closes = at End systolic pressure)
Definition of HTN
Average systolic BP that is >95th centime for age, gender and height on >= 3 occasions
CO formula
HR x SV
However impossible to truly measure SV so use this formula for children: ~ 4-5 L/min/m^2 (BSA)
Thermodilution
what does it measure and how?
Measures CO (direct method)
Catheter fed through SVC into RA → RV → and tip in PA
- > Solution injected
- > Time/temp curve produced
-> CO = area under curve
Fick method
Indirect measurement of CO
- Measures O2 consumption
= O2 consumption/(arterial - venous content difference)
Pulmonary to systemic flow ratio equation normal values What if incr vs decr
Estimates extent to which pulmonary blood flow is increased or reduced
Flow (Q) - surrogate for CO
Q pulmonary = pulmonary vein saturation - pulmary artery sat
Q systemic = systemic arterial sat - mixed venous sat
Qp:Qs = Qsystemic / Qpulm
= (SatAorta-SatSVC)/(SatPulmonary Venous - SatPulmonary Artery)
Normally = 1:1 Left to right shunts > 1.0 Right to left shunts <1.0
There is a step up in saturation in main pulmonary artery (RA 78%, main pulm artery 89%), what is the cause of this shunt?
- PDA
- Aortic blood mixes into ain pulmonary artery - VSD
- LV blood (high pressure ) pushed across into RV both resulting in increasing saturation in main pulmonary artery
L to R shunts cyanotic or acyanotic? causes
ACYANOTIC ASD
- Childhood presentation
- Murmur, exercise intolerance
- R heart enlargement as shunting occurs at atrial level , volume load occurs in RV
PDA nad VSD
Shunting L-> R: volume load occurs straight into pulmonary artery -> lungs -> then straight into L side of heart so get volume loading of L side, not right side of heart
Presentation: - These may not be evident in the neonatal period due to high pulmonary vasc pressures (R heart pressures = systemic pressure) and thus reduced shunting.
Appear at 12 weeks/3mo of age as the PVP back to low baseline and shunting is at its maximum
- Murmur, heart failure, FTT
- L heart enlargement
VSD (30% of all CHD) PDA ASD AVSD (Downs)
Tetralogy of Fallot Clinical findings
Sx
- Onset depends on severity of pulmonary stenosis;
- cyanosis may appear in infancy (2 to 6 months of age) or in childhood
- other symptoms include hypercyanotic spells or decreased exercise tolerance
Clinical
- Central cyanosis
- Clubbing of nail beds
- Grade 3 or 4 long systolic ejection murmur heard at ULSB
- May have holosystolic murmur at LLSB
- Systolic thrill at ULSB
- Normal to slightly increased S1
- Single S2
VSD Clinical findings
VSD ECG
Sx
- Small defects: usually asymptomatic
- Medium or large defects: CHF, symptoms of bronchial obstruction, frequent respiratory infections
Murmur
- Small defects: loud holosystolic/ES murmur at LLSE (may not last throughout systole if defect is very small)
- Medium and large defects: increased right-to-left ventricular impulses; thrill at LLSE; split or loud single S2; holosystolic murmur at LLSE
ECG
- SMall VSD: normal ECG
- Large VSD will produce right ventricular hypertrophy with right axis deviation. At this point there is either an rsR’ pattern in the right precordial leads, or more commonly, a tall monophasic R wave in the right precordial leads reflecting RVH. Also deep S waves in the lateral precordial leads and tall peaked P waves
PDA` Clinical findings
Sx
- May be asymptomatic; can cause easy fatigue, CHF, and respiratory symptoms
Clinical
- Continuous machinery murmur (grade 1 to 5) in ULSE (crescendo in systole and decrescendo into diastole)
- normal S1
- S2may be “buried” in the murmur
- thrill or hyperdynamic left ventricular impulse may be present
R to L shunts - examples
CENTRAL CYANOSIS
Increased pulmonary blood flow
- Truncus arteriosus
- TGA
- Total anomalous pulmonary venous return
PRESENTATION –> heart failure with low sats –> pulmonary congestion as PVR drops –> subtle desalts (93-94%) with high pulmonary blood flow
Reduced pulmonary blood flow
- Tetralogy of fallot (obstruction of blood flow to lungs)
- Tricuspid atresia (no tricuspid valve so no blood flow across PA)
- Ebstein’s anomaly (abnormality of tricuspid valve that may obstruct blood flow to lungs and affect ability of RV to pump bloods to lungs)
PRESENTATION –> Cyanosis –> Oligaemic lung dields –> Significant deterioration clinically with closure of PDA (results in significantly reduced pulmonary blood flow)
Pulmonary vascular resistance calculation Normal value What causes high or low values ?
Pressure drop across the pulmonary/systemic circulation per unit flow in a specific period of time = pressure drop between mean pulmonary artery pressure and LA pressure Rp = mean PA - mean Lap (mmHg)/Qp (L/min/m^2) Normal PVR <3.5 If high this could be normal if in a neonate due to increased pulmonary vascular resistance -> need to then test patients in 100% oxygen to look at vasodilation of pulmonary arteries (should be reversible) –> if doesn’t increase, indicated idiopathic pulmonary HTN HIGH PVR: - hypoxic - elevate Co2 - incr symptoms tone (inotropes) - polycytheamic - PE - pulm oedema - pulm effusion (causes compression) LOW PVR - Oxygen - adenosine - inhaled NO - prostacycin - Ca channel blockers
how does pulmonary vascular resistance compare with systemic vascular resistance
1/6 systemic vascular resistance
Isovolumetric relaxation
Ventricle is relaxing whilst volume stays constant (after ejection when aortic valve has closed again) when ventricular pressure < atrial pressure, mitral valve opens and blood flows from atrium into ventricle
Relaxation phase occurs until mitral phase shuts
Increased preload effect on heart pressure volume loop
Increased end diastolic volume in LV Larger stroke volume Increased stroke work (area under pressure volume curve)
Increased after load
Higher pressure needs to be reached before >aorta but stroke volume is slightly reduced Stroke work (area under pressure volume curve) stays about the same
increased contractility (caused by medication) affect on
blood under more pressure in ejection phase so have longer ejection phase Ejection phase ends when LV p = aortic pressure. Results in larger stroke volume Overall higher stroke work (area under pressure vol curve)
Cardiac cycle
- SVC and IVC -> deoxy blood to RA ->tricuspid valve (3 cuspsl) -> RV
- RV -> pulmonary valve (3 cusps) -> deoxy blood to lungs via pulmonary artery for oxygenation
- pulmonary veins bring oxygenated blood to LA -> mitral valve (2 cusps) -> LV
- LV -> aortic valve (3 cusps) -> oxygenated blood to systemic circulation via aorta
- Systole atrial contraction - firing of SA node induces depolarisation of heart = p wave = atrial contraction -> atrial pressure increases -> ventricular pressure increases as blood flows into ventricles through AV valves.
- AV valves (mitral and tricuspid) close = S1 heart sound
- Isovolumetric contraction (pressure in ventricles increases as volume stays same, valves closed)
- Rapid ventricular ejection (blood ejected from ventricles into aorta/PA
- Reduced V ejection (as pressure in ventricles decrease and aortic pressure also falls, atrial pressure increases as they passively fill)
- Diastole - starts at end of T wave on ECG
- Isovolumetric ventricular relaxation - when P aorta > P ventricles, aortic valve closes to prevent backflow of blood (s2) then pulmonary valve closes shortly after. Pressure in ventricles decr whilst volume stays same
- Rapid ventricular filling - when atrial pressure > ventricular pressure, AV valves open and leads to rapid filling of ventricles
- Diastasis (passive ventricular filling) - 90% of ventricular filling occurs before atrial contraction whilst aortic pressure continues to fall
Layers of heart
- Fibrous Parietal - lines fibrous layer
- Visceral - lines outside of heart muscle
- Serous fluid (pericardial fluid) between partietal and visceral layers)
- heart muscle - myocardial cells and connective tissue between them
What causes heart sounds?
S1 - tricuspid and mitral valves snapping shut when L and R ventricles contract
Then systole (contraction and ejection of blood)
S2 - aortic and pulm valves snap shut, ending systole
Then diastole (relaxation)
CV circulatory changes at birth
- Umbilical cord is cut/clamped -> removal of placenta from foetal circulation -> umbilical arteries and vein constrict/blood clots 2. Baby takes first breath, air enters blood and lungs expand -> air pushes fluid out -> lung pressure/resistance drops -> promotes blood flow into lungs -> Blood returns to L side of heart after going through lungs -> pressure L atria rises -> foramen ovale and PDA closes (detects incr oxygenation of blood in LA and decr prostaglandins as was secreted by placenta; closes by 48 hrs)
Foetal circulation
Foramen ovale - hole between R and L atrium (bypasses foetal lungs which are filled with fluid) Patent ductus arteriosus - connection between PA and aortia These both allow a -> Right to left shunt -> Blood bypasses lungs and goes straight to aorta Foetus isn’t breathing anyway so relies on Oxygen to be delivered from placenta via umbilical VEIN (x1; note is oxygenated blood) in cord -> ductus venous in liver -> IVC -> RA -> 1. RV 2. via patent foramen to LA -> LV -> around foetal circulation via aorta RV blood can also go to pulm artery to lungs or via PDA to aorta Blood delivered to foetal organs/tissue -> deoxy blood returned via umbilical arteries (x2) back to placenta for reoxygenation Note foetal and maternal blood do NOT mix in placenta RBC stay in their own circulation but they transfer only O2 and co2 across placenta -> foetal Hb has more affinity for O2 than maternal Hb
Ductus venosus
The conduit from umbilical vein (carries oxygenated blood from mums placenta to foetus) to the fetal IVC -> IVC then carries oxygenated blood to foetal RA
In foetus which side of the heart has higher pressures and why and what does this result in?
High R side pressures due to high pulmonary resistance (fluid, no oxygen -> pulm vessels constrict to redirect blood flow) This means that blood flow is directed through foramen ovale into LA (as pressures are lower) rather than through pulm A to lungs
Ductus arteriosus
Connection between pulmonary trunk and aorta Pressure aorta < pressure pulmonary trunk Means that blood that DOES enter the pulmonary trunk/artery ends up being redirected to the aorta -> systemic circulation (bypasses lungs)
CV Blood pressure regulation What is the rate of this response?
Carotid and aortic arch baroreceptors (Stretch detection; more pressure = more stretch) Incr stretch detected -> signals to brain -> PS activation -> decr HR, decr SV and vasodilation -> decr BP Decr BP -> Decr stretch detected -> symathetic NS activation -> incr HR and SV and vasoconstriction -> incr BP OCCURS in sec-min (very rapid)
Pressure formula
Flow (Q) x Resistance (R) = (SV x HR) x R
Cardiac pressure/ECG/volume vs time graph
What is pulmonary artery wedge pressure (PAWP) used to measure and how does it work?
Pulmonary artery wedge pressure = Left Atrial Pressure
Most commonly used to quantify degree of mitral stenosis (also will result in high LA pressure)
Also gives indication of LV function (LV failure -> high LA pressure > 20mmgHg)
Method: PCWP is measured by inserting balloon-tipped, multi-lumen catheter (Swan-Ganz catheter) into a peripheral vein (e.g., jugular or femoral vein), then advancing the catheter into the right atrium, right ventricle, pulmonary artery, and then into a branch of the pulmonary artery
red flags for patholoical murmurs
Red flags that increase the likelihood of a pathologic murmur include
- a holosystolic or diastolic murmur
- grade 3 or higher murmur
- harsh quality
- an abnormal S2
- maximal murmur intensity at the upper left sternal border
- systolic click
- increased intensity when the patient stands.
wide split fixed S2
ASD
Systolic ejection click
Semilunar valve (aortic or pulm valve) stenosis
Where to listen on chest for different heart valves/defects
Upper right sternal border (URSB) - aortic valve
Upper left sternal border (ULSB) - pulmonary valve clicks
Lower left sternal border (LLSB) - Tricuspid valve and ventricular septal defects
Apex - aortic or mitral valve
ASD sx and clinical findings
Sx
- Usually asymptomatic and incidentally found on physical examination or echocardiography; large defects can be present in infants with CHF
Clinical
- Grade 2 or 3 systolic ejection murmur best heard at ULSB; wide split fixed S2; absent thrill; may have a grade 1 or 2 diastolic flow rumble at LLSB
MOA
Left (higher pressure) -> Right (lower pressure) shunt Types - Ostium secondum is failure of foramen ovale to close - Ostum primum is congenital, when it involves the AV valve (common in downs) ECG: - Superior axis deviation - Incomplete RBBB Clinical: - asymptomatic - splitting of 2nd heart sound (because you’ve got more blood going into pulmonary circulation so pulmonary valve shuts slightly later than aortic valve) - pulmonary flow murmur - diastolic rumble across tricuspid valve - no lung changes
ECG
- Small uncomplicated - normal
- First degree heart block (prolongued PR interval)
- R axis deviation
- Complete RBBB (wide QRS with rsR’)
TOF
CLinical findings
Exam
Sx - Onset depends on severity of pulmonary stenosis; cyanosis may appear in infancy (2 to 6 months of age) or in childhood; other symptoms include hypercyanotic ‘Tet’ spells (when crying) or decreased exercise tolerance
Exam
- Central cyanosis; clubbing of nail beds;
- grade 3 or 4 long systolic ejection murmur heard at ULSB; systolic thrill at ULSB; single S2
ECG
- Increased right ventricular forces as evidenced by tall R waves in V1.
- Additionally, right atrial enlargement is manifested by prominent P waves in V1 (*).
- Right ventricular hypertrophy is demonstrated by a rightward deviated axis.
CXR
- small boot shaped heart
CLinical findings pulmonary stenosis
Sx
- Usually asymptomatic but may have symptoms secondary to pulmonary congestion
Clinical
- Systolic ejection murmur (grade 2 to 5) heard best at ULSB radiating to infraclavicular regions, axillae, and back
- Nnormal or loud S1; variable S2
- Systolic ejection click may be heard at left sternal border and may vary with respiration
Clinical findings coarcatation of aorta
Sx
- Newborns and infants may present with CHF; older children are usually asymptomatic or may have leg pain or weakness
Clinical
- Systolic ejection murmur best heard over interscapular region; normal S1 and S2; decreased or delayed femoral pulse; may have increased left ventricular impulse
Cinical findings aortic stenosis
Sx
-Usually asymptomatic; symptoms may include dyspnea, easy fatigue, chest pain, or syncope; newborns and infants may present with CHF
Clinical
- Systolic ejection murmur (grade 2 to 5) best heard at URSE with radiation to carotid arteries/neck; left ventricular heave; thrill at ULSB or suprasternal notch
CXR: prominent LV +/- post-stenotic aortic dilatation
ECG - findings of L hypertrophy/L heart strain
- The S wave in V1 is deep
- the R wave in V4 is high
Often some ST depression can be seen in leads V5-V6, which is in this setting is called a left ventricular strain pattern
TGA clinical findings
Sx
- Variable presentation depending on type; may include cyanosis or CHF in first week of life
Exam
- Cyanosis; clubbing of nail beds; single S2; murmur may be absent or grade 1 or 2 nonspecific systolic ejection murmur; may have a grade 3 or 4 holosystolic murmur at LLSB and mid-diastolic murmur at apex
Tricuspid atresia clinical findings
Sx
- Early-onset cyanosis or CHF within the first month of life
Exam
- Cyanosis; clubbing of nail beds; normal pulses; single S2; holosystolic murmur at LLSB or midsternal border; murmur may be absent; mid-diastolic flow murmur at apex may be present
Hypoplastic L heart syndrome clinical findings
Sx
-May be asymptomatic at birth, with circulatory collapse, shock (met acidosis), tachypnoea, cyanosis, and CHF developing with duct closure (d1-3)
Exam
- Hyperdynamic precordium; single S2; nonspecific grade 1 or 2 systolic ejection murmur along left sternal border, decr peripheral pulses
Truncus arteriosus
presentation and exam findings
- Onset of CHF in first few weeks of life; minimal cyanosis
Exam
- Increased cardiac impulses; holosystolic murmur (ventricular septal defect); mid-diastolic rumble
How to calculate mixed venous sat
Sat MV = (3xsat SVC + 1xsat IVC / 4
Qp (pulm flow)
VO2 / (Pvsat - Pasat) x Hb x 1.36
Assume vo2 120 if not given
express sats as frac (85% = 0.85)
Pulmonary vasc resistance
pressure difference across lungs
/ cardiac output (Qp)
Downs syndrome - cardiac lesions associated
ASD #1
AVSD
VSD
PDA
TOF
What stimulates PDA closure
- Incr O2 is the biggest factor that influences closure
- Decr prostaglandins (from placenta)
3 main foetal shunts
- Ductus arteriosus (pulm a to aorta)
- Ductus venosus (umbi vein to IVC so bypass liver)
- PFO (R atrium to L atrium)
What triggers muscle contraction in cardiac myocardium
Release of stored Ca frmo sarcoplasmic reticulum
Ca binds to troponin to get tropomysin heads to move away so acitn and myosin can bind together
then ATP can bind -> hydrolysed -> ‘power stroke’ = muscle contraction
1 child with TOF ?risk of recurrence in another child
2-4%
What heart sound occurs with pulmonary HTN?
Loud second heart sound
What is physiological splitting of second heart sound
Separation between aortic and pulm valve closure on inspiration (aortic closes before pulmonary due to greater systemic pressure)
What is fixed splitting?
Fixed splitting - splitting of 2nd heart sound with both inspiration AND expiration = ASD
ASD - types
Secondum - 75% (hole in fossa ovalis = ostium secondum)
Primum - assoc w cleft mitral valve or AVSD
Turners syndrome - assoc CV defect
Bicuspid aortic valve (two cusps instead of three) - 16%
Coarctation (narrowing) of aorta - 11%
Other Aortic arch anomalies
Noonan syndrome assoc CV defect
Pulmonary valve stenosis (39%)
Hypertrophic cardiomyopathy (10%)
Atrial septal defect (8%)
Tetralogy of Fallot (4%)
VACTERL syndrome assoc CV defect
Ventricular septal defect (VSD)
Atrial septal defects
Tetralogy of Fallot
Di GEorge syndrome assoc CV defect
Conotruncal defects:
- TOF
- Truncus arteriosus
- Interrupted aortic arch
Causes of Prolonged QT
Hypokalaemia
Hypocalcaemia
Congenital Long QT sydnroem
Myocarditis
Malnutrition
Medications (antipsychotics, antiarrhythmics, antidepressants, antibiotics, ondansetron)
ECG changes hyperkalaemia
Peaked T waves
Prolongued QRS (>3 squares)
Prolongued PR interval (>5 sq)
Conduction blocks
ECG changes of Wolf Parkinson White
BRoad QRS with delta wave
Short PR interval
ST depression
Risk of re-entrant SVT
Normal PR interval
3-5 small boxes (120-200ms)
→ 160ms in children
→ 180ms in adolescents
Types of 2nd degree heart block
2nd degreee Mobitz type 1 (benign) - progressive lengthening of PR interval with ultimate dropped P wave
2nd degreee Mobitz type 2 (pathological) - pr interval LONG (fixed) with intermittent dropped QRS
What is pulsus paradoxus
Systolic BP drop of >10mmhg with inspiration
Main cause is cardiac tamponade
asthma
PE
pericarditis
hypovolaemia
Mobitz type 1 vs mobitz type II
Second degree AV block = intermittent failure of conduction to the ventricles
type I - Wenckebach = progressive lengthening of the PR interval followed by a non-conducted P wave (dropped QRS). The PR interval then shortens and the cycle is repeated.
type II - intermittent non-conduction of P waves without progressive prolongation of the PR interval. It is due to a failure to conduct below the AV node (His-Purkinje system) and is more likely to be related to structural damage to the conducting system. Can progress to third degree/complete heart block.
ECG changes hypokalaemia
Flattened p waves
Depressed ST segment
U waves
T wave inversion
What is this condition (See ECG)?
- how might it present
- classic ECG findings
Brugada syndrome is due to a mutation in the cardiac sodium channel gene
Predisposes to VT, VF
Often fhx sudden death or may present as sudden collapse (may be unmasked by fever/infection, drugs, ischaemia etc)
Brugada sign = Coved ST segment elevation >2mm in >1 of V1-V3 followed by a negative T wave.
abnormally tall P waves in most leads =
RA enlargement
Third degree heart block - what is this?
= Complete heart block
P waves and QRS complexes are completely dissociated
What types of heart block is cardiac pacing potentially indicated in
second degree Mobitz type II and third degree/complete heart block
Abnormally wide P waves =
left atrial enlargement
ECG axis interpretaton
Look at leads I, II, AVF
Normal axis (0 to +90deg): Positive I, II, aVF
LAD (0 to -90): Positive I, Negative aVF (II + or neutral)
RAD (90 to 180): Negative I, Positive II and aVF
Extreme AD (-90 to -180): Neg I, Neg II, Neg AVF
ECGs - normal RS wave progression for neonates vs children
Look at V1 and V6 first
Neonates: V1 the R wave is dominant, with S wave dominance in V6 (RV dominance)
Children >3yo: S wave dominance in V1 and R wave dominance in
V6 (LV dominance)
In between: R wave is dominant in both V1 and V6
ECG changes for
- incr RV forces (ex RV hypertrophy)
- incr LV forces (ex LV hypertrophy)
RV: tall R waves in lead V1 and deep S waves
in lead V6.
LV: Deep S waves V1; tall R waves V6
Normal t wave position in V1 through different age groups
What if it is the opposite to normal pattern?
<1 week and >10yo: upright
1week-10yo: inverted (if upright, suggests RV hypertrophy)
Q waves and inverted t waves in lead aVL = ?
Anomalous origin of the left coronary artery from the pulmonary
artery (ALCAPA)
Q waves in leads V1-V3 = ?
congenitally corrected transposition of the great
arteries
Upper limit of QRS duration is
ddx for QRS prolongation
120ms (three small squares)
Prolongation points to abnormal ventricular
depolarization for which there are several causes
- bundle branch block (RBBB RsR’ more common than LBBB in kids)
- an ectopic ventricular origin of cardiac activation (ventricular ectopy or pacing)
- electrolyte disturbances
- drug toxicity
Difference between RBBB and incomplete RBBB
RBBB- WIDE QRS and RsR’. common post TOF repair.
vs Incomplete RBBB has normal QRS interval (<120ms or 3 small sq) with RsR’ . Usually benign, but may be associated with atrial septal defect
Normal accepted values for ST segment changes in children
a shift (elevation/depression) of up to 1 mm may
be normal in limb leads, whereas up to 2 mm is normal in left
praecordial leads attributed to early repolarization of the heart.
What is the calculation for corrected QT interval and what is the normal value
QTc = QT / sqroot(RR)
<= 440ms
What are features of SVT on ECG
Rate >200bpm
Normal QRS complex
Lack of discernible p waves
Features of ventricular tachycardia
BROAD Qrs
QRS complexes can be regular = monomorphic VT arising from single focus
OR QRS irregular complexes - can have multiple foci. ex: Torsades de Pointes (can be sugg of underlying long QT)
Q waves - what is abnormal on ECG?
Torsades de pointes
Can be sign of underlying long QT syndrome
What are conotrunkal defects, give examples and what syndrome are they frequently seen in?
Cardiac outflow tract anomalies that include:
- tetralogy of Fallot, pulmonary atresia with ventricular septal defect
- double-outlet right ventricle (DORV)
- double-outlet left ventricle
- truncus arteriosus
- transposition of the great arteries (TGA)
Frequently found in patients with 22q11.2 deletion syndrome .
What is first degree heart block
PR interval is prolonged
This in itself is not problematic, but may progress to higher degrees
of AV block
What is eisenmengers syndrome
Compication of or most severe form of pulm htn/CHD
= Pulmonary hypertension at systemic level due to high PVR with reversed or bidirectional blood flow through a septal defect
(PVR so high that it trumps systemic vascular resistance and causes reversal of shunt from L->R to R->L)
Pulm HTN
- CLnical findings
- ECG findings
Clinical:
- Right ventricular lift/tap
- S2= loud and single
- Ejection click and early diastolic decrescendo murmur of PR
- Holosystolic murmur of TR may be audible LLSB
- Signs of RHF
ECG: RAD and RVH +/- strain pattern
Treatment of Pulm HTN
Corrective sx for underlying CAD
Treatment of other underling diseases – such as CF, asthma, pneumonia bronchopulmonary dysplasia
Anticoagulation and antiplatelet
Pharmacologic treatment of Pulm HTN
For ‘responders’ – pulmonary vasodilators are used in ‘responders’
- > Nifedipine – Ca channel blocking agent
- > Prostacyclins – epoprostenol
- > Endothelin receptor antoagonists – bosentan, sitaxsenton, sildenafil, NO inhalation
For ‘non responders’:
- > NO inhalation
- > Atrial septectomy
- > Lung or heart transplant
Long QT syndrome
What is it
What is the pathyphys
Genetic disorder of ventricular repolarization characterized by a prolonged QT interval on the ECG and ventricular arrythmia èusually torsades de pointes that may result in SCD
Pathophys
- Long QT interval = abnormally long repolarisation phase
- Channel defect prolongs the myocardial recovery from excitation à prolonged potassium efflux
- Leads to increased period of refractoriness
- This predisposes re-entry pathway (wave of excitation wandering around the ventricle) à VT
- Types
- Type 1 - 35%; excessive K efflux. arrhythmia is classically triggered by exercise or emotional events
- Type 2 - 25%; excessive K efflux. Arrhythmia is classically triggered during sleep/rest
- Type 3 - minimal Na influx
what defect is assoc with complete RBBB in 90% of cases?
Repaired TOF
Transposition of great arteries - Dextro
-> RA to RV connected to aorta, LA connected to PA. Survival depends on a shunt to allow for mixing, otherwise would not have oxygenation.
Levo-TGA = ventricles on wrong side -> RA to LV to aorta. LA to RV to pulm circ (usually asymptomatic)
Q waves - when are they pathological?
Pathological in V1
What does this ECG show?
Ventricular tachycardia
ECG features of LV hypertrophy
Deep S wave V1,2
Tall R wave V5,6
T wave inversion V5-6
LAD
ECG features of RV hypertrophy
Tall R wave in V1
Deep S wave in V6
ABnormal t wave direction in V1 (should be upright in newborns and >age of 10, otherwise inverted)
Mx of cardiac failure
Sit pt upright
O2
Diuretics - furosemide, spironolactone to reduce pre and afterload
Inotropes (PO digoxin or IV dobutamine/dopamine if severe)
Vasodilators - captorpil, hyralazine to reduce afterload
I+V if needed
Causes of peripheral pulmonary stenosis
Williams syndrome
Congenital rubella syndrome
Alagille syndrome
CHD (ASD, VSD, PDA, TOF, supravalv AS)
Features of ALagille syndrome
PRogressive bile duct dilatation
TOF
BUtterfly vertebrae
Npehritis
Facialfeautres
POsterior embrotoxon
~``
`Features of congenital rubella syndrome
Myocarditis
PDA
Micropthalmia
Cataracts
Deafness
Features of Williams Syndrome
Supravalvular AS
HyperCa
Mental retardation
Elfin facies
Teratogens associated with CHD
Sodium valproate (ASD, VSD most commonly)
Lithium (ebstein anomaly)
Phenytoin
Alcohol
Rubella
SLE/Srogrens
Diabetes
What hypertrophy do you get with a VSD?
Left (right if pulm HTN)
Indications for surgical closure in VSD
Normally close spontaenously during first few days of life
Severe sx (heart failure, recurrent chest infections etc) w FTT
pulm HTN
aortic regurg
persistent shunting > 10yo
ECG findings for ASD ostium primum vs secundum
Seccundum (defect in atrial septum only)
- RAD, incomplete RBBB +/- RVH
Primum (failure of development of septum primum diving mitral and tricuspid valves and cleft in anterior leaflet of mitral valve; assoc w Downs syndrome)
- Get mitral regurg.
- LAD + incomplete RBBB, RVH
Mx of ASD primum vs seconddum
primum - always need surgical repair
secondum - usually close spontantously; surgical repair if symptomatic or at 3-5yrs if perisistent
AVSD
what syndrome is it assoc with?
Sx?
ECG and CXR features
Assoc w downs syndrome
involves mitral and tricuspid valves and atria Ventricles
Sx - severe w ealry onset heart failure, recurrent pneumonia, FTT, pulmonary HTN
Large L-> R shunt across atria and ventricles
ECG - Left/extreme axis w biventricular hypertrophy and incomplete RBBB (narrow QRS)
CXR - cardiomegaly, pulm plethora
Mx - surgical repair within 6 mo to prevent pulm HTN developing
Classic PDA murmur
Preterm infants - systolic murmur LSE
older - MAchinery murmur below L clavicle
Management of PDA
Fluid restriction
Indomethacin if <34/40 and within 3/52 of birth
Surgical ligation if failure of medical management
WHat hypertrophy do you get with PDA
LVH (right if pulm htn present)
What syndrome is assoc w pumonary stenosis
Noonan syndrome
Indication for surgical intervention in pulmonary stenosis
Balloon dilatation or surgical valvotomy if:
- If pressure gradient across valve is > 50mmHg
- Severe pulm valve thickening
- critical neonates (duct dependent circulation w cyanosis)
indications for surgical mx of aortic stenosis
Balloon or surgical valvotomy if:
- Neonate (followed by vlave repalcement later on)
- Older children if pressure gradient across Aortic valve is >50mmHg
What is coartation of the aorta?
Presentation
CLincial signs
ECG findings
CXR
Constriction of descending aorta
REsults in LV outflow tract obstruction
Duct dependent for circulation
Presenation
- circulatory collapse in first week of life when duct closes
OR asymptomatic murmur (ejection systolic)
HTN in upper limbs only, weak pulse in legs (do 4 limb BPs, pulses)
Radiofemoral delay
Heart failure
ECG - RVH in noenates (bc RV is systemic) and LVH in older kids
CXR: normal +/- prominent LV
Cardiomegaly w increased pulmonary vascular markings
Rib notching (collaterals forming beneath ribs) if >8yo
Mx of duct dependent circulation
PGE2 infusion
Ventilation and inotropes as needed
Conditions with duct-dependent SYSTEMIC circulation in neonates (and how does this present)?
- COLLAPSE due to duct-dependent sytstemic circulation = L ventricle/aortic outflow obstruction
a) Coarctation of aorta
b) Hypoplastic L heart syndrome
c) Critical aortic stenosis
d) Interrupted aortic arch
Conditions with duct-dependent pulmonary blood flow (and how do these present)?
Cyanosis in first week (anything with RV or pulm artery outflow obstruction)
a) Transposition of great arteries
b) Pulmonary atresia w VSD
c) Critical pulmonary stenosis
d) Pulmonary atresia w no VSD
e) Tetralogy of fallow
f) Tricuspid atresia
g) TAPVD w obstruction
h) Ebstein anomaly
-
TOF
Features
Pulmonary stenosis - note severity of cyanosis depends on severity of PS
VSD
Overriding aorta
RV hypertrophy (Secondary to pulmonary stenosis)
*Note - no pulmonary HTN as pulm stenosis is protective*
Tricuspid atresia
Features:
- Absent tricuspid valve (no passage between RA and RV)
- ASD (so blood can get to LA)
- VSD (so mixed blood from LA -> LV can get to RV -> lungs)
- Small, non-functional RV (as no blood flow to R ventricle)
CLinical findings:
Cyanosis at birth and increases with age as pulmonary flow decreases
Systolic murmur at LSE
Single S2
ECG: LAD or superior axis
CXR: small haert w pulm oligaemia
Mx of TOF
O2
IV fluids
Morphine
Propanol IV (decr peroph vasc resistance)
Bicarb (if acidotic)
+/- IPPV (paralysed to decr O2 demand)
+/- Noradenaline (decr systemic vasc resist so incr pulm blood flow)
Surgery (high mortality if not corrected) - at 4-12 months of age close VSD and relieve RVOT obstruction
Conditions associated with TOF
DOwn sydnrome
22q microdeletion (DiGeorge) syndrome
CHARGE syndrome
VACTERL
What shunt do you get with TOF
Right -> Left shunt (due to pulmonary stenosis)
What is double inlet ventricle?
Clincical features
CXR
Both atria empty into single ventricle
Both PA and aorta arise frmo this same ventricle
Features depend on hte pulm blood flow
- High pulm blood flow - pink w severe heart failure and eventually eisenmenger reaction
- Low pulm blood flow - cyanosis w no heart failure
CXR - cardiomegaly w pulm plethora (HF) or oligaemia (cyanotic)
Management of tricuspid atresia
- initial ‘palliation’ with Blalock-Taussing shunt (anastamosis of subclavian artery to pulmonary artery)
- Definitve palliatoin at 2-5yo with Fontan procedure (SVC and IVC connected directly to pulmonary artery.
Features of Ebstein anomaly
- ABnormal tricuspid valve ( leaflets adherent to ventricle wall and displaced distally)
- > results in RVOT obstruction - ASD
- Small, underformed RV
- WPW syndrome type B
- Functional pulmonary atresia
Clinical
- cyanosis
- FTT
- SVT, extrasystoles
- asymptomatic
Mx of Ebstein anomaly
Pulmonary vasodilation (O2, prostacycln, NO) or PGE2 to open duct
Mx cardiac failure
Tricuspid repait/replacement
Closure of ASD
Ablation of WPW pathway
Hypoplastic L heart syndrome
What it is
CLin ft
WHat is it
- Small L ventricle
- Small mitral valve and aortic valve atresia
- SMall asc aorta
Clinical ft
- Collapse/impalpable peripheral pulses/acidosis
Pulmonary atresia
- Features
Features
- Complete absence of pulmonary valve + VSD and PDA (or collateral vessels)
- Complete absece of pulmonary valve, NO VSD, a PDA, hypoplastic R heart, normal pulmonary arteries (Supplied by PDA). COmpletely duct dependent for pulmonary circulation.
Note: PDA supplies mixed blood from aorta directly to pulmonary artery -> lungs
Clinical
- Early neonatal cyanosis
- Continuous murmur at the back due to collaterals with VSD (not heard at front)
- Single S2
ECG: RA and RVH
CXR: prominent RA, pulmonary oligaemia +/- R soded aortic arch and small boot shaped heart if VSD present
Pulm atresia
Mx
- PGE2 if duct dependent
- Surgery
Total anomalous pulm venous drainage (TAPVD)
3 types
SUpracardiac - pulm veins drain into SVC rather than LA. ‘snowman’ appearance on cxr with supracardiac shadow.
Cardiac - pulm veins drain into r atrium rather than LA
Infracardiac - pulm veins drain into IVC, ductus venosus, portal vein rather than LA. This is associated with obstruction to pulmonary venous return. hazy lung fields/’white out’ on CXR
REquires PFO, PDA or ASD to allow mixing of bloods between R and L sides of heart
What is this CXR of?
sx
Supracardiac TAPVD
(no obstruction)
- mild cyanosis
- cardiac failure
- recurrent chest infx
- pulm htn (incr blood flow RA -> RV)
What is this CXR of?
Sx
Obstructed infracardiac TAPVD
Sx - severe cyanosis, resp distress, hepatomegaly, no murmurs
Genetic causes of long-QT syndrome
- Jervell-Lang- Neilson
vs Romano-ward
JLN: AR, long QT + congenital deafness
trigger: fear, excitement, exercise
Romano-WArd: AD, isolated long QT
Rheumatic fever
Cause
Features/diagnosis
Cause is Group A beta-haemolytic strep infection (same strep that causes strep throat/scarlet fever)
Strep throat infection (supported by ASOT or throat cultures) is followed 2-6 weeks later by polyarthritis, fever, malaise and cardiac sx
Need 2 major criteria or 1 major and minor for diagnosis
Major :
- Carditis
- polyarthritis (large joints, migratory)
- sydenham chorea (involuntary movement)
- erythema marginatum (pale red rings in recurrent crops, not itchy)
- Subcut nodules on extensor surfaces (hard, painless, pea-like)
Minor
- Fver
- Arhtralgia
- Long PR interval or elevated ST
- Raised ESR or CRP
- Leucocytosis
- Previous Rh fever
Treatment of Rh fever
Bed rest (if active fever, carditis or arthritis)
High dose aspirin
Steroids for carditis
Treat haeart failure
Benzylpenicillin IM or oral penicillin
Then lifelong penicillin prophylaxis
Long term cx of RH fever
Mitral stenosis +/- aortic stenosis
Clinical ft of infective endocarditis
Always think of this as a ddx in pt w known cardiac defect who is unwell
- sustained fever, night sweats, malaise
- new cardiac murmur
- persistence of fever after acute illness
- splenomegaly, splenic rub (common)
- Arthritis of large joints (common)
- splinter haemorrhages
- roth spots (retinal haemorrhages)
- Janeway lesions (erythematous macules on thenar and hypothenar eminences)
- Osler’s nodes (hard swellings on toes, fingers, soles, palms)
- EMbolic phenomena (cerebral, pulm, coronary, peripheral)
- Renal lesions-> haematuria, fsgs, renal failure
- Clubbing (late sign)
Mx of endocarditis
4-6 weeks antimicrobial tx (2 weeks IV)
Abx prophylaxis for future proceudres
Surgery if extensive valve damage/cardiac failure, vegetations or embolisaiton
What is infective endocarditis?
Infection of endocardium, particularly predisposed by CHD or previously damaged/abnormal or prosthetic valves
WHat is myocarditis and what is it caused by?
Inflammation of heart with necrosis and fibrosis causing weakening of heart muscle with cardiac and resp failure.
Can become chronic
Causes
- infectious
- viral (coxsackie, adeno)
- bacterial - dipheria, ricketsia
- fungal
- parasitic - toxic (related to pnuemonia, sepsis, drugs)
- connective tissue disease
- Idiopathic
Myocarditis
CLinical features
CXR
ECG
Bloods
CLinical ft
- cardiac failure (tachycardia, weak pulses, resp distress)
- arrhytmia
- sudden death
- can be asympatomic (eg in teens)
CXR - cardiomehgaly (pericardial effusion), pulm plethora
ECG; Arrhythmias
Bloods - elevated CK, LDH, troponin
Mx of myocarditis
Supportive tx for cardiac failure, arrhythmas
ECMO may be needed
Transplant if chronic/refractory heart failure and irreversible damage to heart
Which congenital long QT syndrome which is associated with deafness?
Jervell-Lang- Neilson syndrome
Causes of central cyanosis (generally)
Lung disease
Caardiac disease
PPHN
Methaemoglobinaemia
How do you distinguish between cardiac and resp cause for central cyanosis?
Nitrogen washout test
- baby is given >90% oxygen to breathe for 10 min
If paO2 rises to above >100mmHg, the cause is resp or central disorder
If paO2 doesnt change (or small rise but remains <100), cause it cardiac or PPHN
MOA PGE2
SE
MOA - ductal smooth muscle relaxant. keeps duct open
SE: hypotension
fever
apnoea
jitteriness
What is the differential for this presentationL
Cyanosed, well baby
Nil obvious resp or cardiac disease
Normal hyperoxic test
Blood remains ‘brownish’ colour after breathing O2
Methaemoglobinaemia
- Iron in Hb is in the ferric (Rather than ferrous) form, non-functional and brown in colour
- diagnose this on spectrophtometry of blood (Reveals metHb)
- treat with reducing agents (ascorbic acid or methylene blue) or exchange transfusion
Spot diagnosis
Child presentting with retrosternal chest pain radiation to neck or L shoulder tip, better on sititng forwards, varies with respiration
Pericarditis
Raditation to L shoulder tip/neck it due to innervation of phrenic nerve C3,4,5
Causes of acute pericarditis
Coxsackie vairus is 1/3 of cases
Staph, Haemophilus influenzae, Tb
Rh fever
Malignancy (Hodgkin disease)
ECG findings of pericarditis
ST elevation (saddle)
T wave inversion
Pericardial effusion
ECG, CXR findings
how do u diagnose it?
All cases of acute pericarditis eventually develop a pericardial effusion
ECG- small voltages
CXR - large globular heart
Echo is diagnostic
Clinical features of acute pericarditis
Decr cardiac output
Impalpable apex beat
Soft heart sounds
Friction rub
Pulses paradoxicus (BP incr on respiration)
Hypotension
Kausmal’s sign (neck veins distended on inspiration
Raised JVP w Friedrich’s sign (steep y descent)
Clinical features of CONSTRICTIVE pericarditis
Cardiac failure - dyspnoea, sweating, hepatosplenomegaly, ascites, peripheral oedema
Decr ventricular filling - pulsus paradoxus, kusmaul’s sign, friedrich’s sgn
AF Pericardial knock (loud 3rd heart sound)
Causes of cosntrictive pericarditis
tb
Acute pericarditis
Haemopericardium
Systolic heart failure
Diastoilc heart failure
Effect on ejection fraction (SV/preload)
Systolic EF = reduced (less than 50-70%)
Diastolic EF = preserved EF (because preload or filling capacity is also reduced)
Cuases of L sided heart failure
Systolic (pumping - most common) cuased by:
- IHD
- Long-standing HTN (Arterial pressure ++ -> harder to pump against -> L sided hypertrophy -> this increases O2 demand of myocardium but also reduces supply as the coronary arteries are squished/narrowed)
- Dilated cardiomyopathy (chamber grows which increase filling/preload but musclular walls thin over time which reduces their strength for contractions)
Diastolic (filling) caused by:
- Concentric cardiomyopathy (incr muscle wall mass results in less room in chamber for filling)
- long-standing HTN
- Aortic stenosis
- hypertrophic cardiomyopathy (genetic) - Restrictive cardiomyopathy (heart muscle stiffer and less compliant so less able to stretch and fill)
What is the main mechanism of oedema in heart failure
Activation of RAS system due to decr CO and decr perfusion of kideys
LEads to Na nad water retention in order to increase preload/filling and thus contractility and CO
L sided heart failure consequences and sx/signs
Pulmonary oedema -> dyspnoea nad orthopnoea; inspiratory creps on ausculation
Right sided heart fialure causes
OFten caused by L sided HF (-> biventricular HF)
L -> R cardiac shunt (ASD or VSD) -> incr fluid volume on R side leading to concentric hypertrophy which elads to ischaemia (and thus systolic failure) and reduced filling/preload (and thus diastolic failure)
Chronic lung disese -> hypoxia -> pulm arteriole constriction -> increased pulm BP = pulmonary HTN -> Cor pulmonale = R sided heart failure (as harder for R ventr to pump against)
Sx/signs of R sided heart failure
Pitting oedema
Ascites
Hepatomegaly
Incr JVP
Truncus arteriosus
clin ft
BACKGROUND
- Only a single arterial trunk with a truncal valve leaves the heart and gives rise to the pulmonary, systemic, and coronary circulations.
- A large perimembranous infundibular VSD
- The truncal valve may be bicuspid, tricuspid, or quadricuspid, and it is often incompetent.
CLN FEATURES
- Cyanotic (may be seen immediately after birth. Worsens as PVR increases with L to right shunting)
- Ejection click
- Ejection systolic murmur at R and L USB
- Signs of left and right heart failure (develop several weeks after birth)
What features influence the degree of L->R shunting of blood in ASD?
- Size of ASD
- Relative compliance of ventricles
- > In infants the right ventricular wall is thick and poorly compliant (due to high inutero periph vasc resistance) – this LIMITS the left to right shunt
- > As the infant becomes older and pulmonary vascular resistance drops, the right ventricular wall becomes thinner (ie. more and the L to R shunt across the ASD increases
- > This is why signs of ASD occur in children 3-4 years of age (if previously undiagnosed) because degree of shunting is much greater
Coronary artery fistula
clin ft
mx
Clinical ft -
ACYANOTIC
Continuous murmur all over precordium
Murmur more likely to be present at birth as not as reliant on fall of PVR
Patients are usually asymptomatic.
However, CHF may develop if the shunt through the fistula is large.
Mx -
Except for the very small coronary to PA fistulas, elective surgery is indicated for most fistulas as soon as the diagnosis is made to prevent complications such as subacute bacterial endocarditis (SBE), fistula rupture, myocardial infarction, and possible sudden
Ejection click (head on auscultation)
- What is it?
- What causes it?
What is it?
High-pitched sounds that occur at the moment of maximal opening of the aortic or pulmonary valves. They are heard just after the first heart sound
What causes it?
- Dilated aorta or pulmonary artery - systemic HTN, pulm HTN, TOF
- The presence of a bicuspid or flexible stenotic aortic or pulmonary valve
OUtlet/conoventricular VSD - what can this eventually lead to?
Very close to aortic valve
Can lead to aortic regurg - > decr exercise toleratnce
Dextro vs levo tga
LEvo (congenitally corrected) TGA - RA -> LV -> pulmonary artery (acyanotic)
Dextro TGA - RA -> RV -> aorta (cyanotic)
Anomolous left coronary artery
L coronary artery arises abnormally from pulm artery instead of from aorta
Results in inadequate perfusion of L pulm artery -> lateral ischeamia, infarction, fibrosis of lateral leads
Get ST elevation in lateral leads of ECG +/- RV/LVH
Results in heart failure -> death in first 6 months of life if untreated
Boot shaped heart on ECG = ?
Tetralogy of fallow
Egg on a strig CXR = ?
Transposition of great arteries TGA
tet spell physiological changes and how does this change the murmur?
Crying/defecation/hypotension -> decr in systemic vascular resistance -> incr R to left shunting of blood across VSD -> leads to reduced blood flow across pulmonary valve (where RVOT is) -> softer murmur
Cleft defects + CHD = ?
Di GEorge syndrome
q11.2 deletion frmo chromosome 22
Conditions assoc w VSDs
T21
DiGoerge/22q11
Turners syndrome
condition assoc w Valvular pulmonary stenosis
Noonans syndrome
Condition assoc w Coarc
Turners
conditions assoc w floppy valves (aortic regurg or mitral valve prolapse -> MR)
Marfans
Ehlos danlos syndrome
Loeys Ditz syndrome
AD / denovo mutations
Similar features to Marfans
- incr armspan:height ratio
CARDIC: dilated aortic root -> aortic aneurysm or dissection
- widely spaced eyes (hypertelorism)
- bifid uvula
- Scoliosis, joint laxity, arachnodactyly (abnormally long/slender finers and toes)
Di GEorge syndrome
22q11 deletion
Craniofcaial - Prominent nose, Small mouth, Small ears
Palalte -bifid uvula, cleft palate (but NOT lip)
Cardiac - Conotruncal abnormalities (TOF, Truncus arteriosus, interrupted aortic arch, VSD)
Immune - Thymic hypoplasia -> impaired cell fxn
Endocrine: parathyroid deficiency + hypocalcaemia; GH deficiency
Developmental delay, behavioural problems, ID
Indications for bacterial endocarditis prophylaxis in kids
Is only recommended prior to:
- Dental procedures
- Invasive respiratory procedures (T&As, bx, incisions)
- Invasive GU procedures
In high risk patients:
- Unrepaired cyanotic heart defects
- Previous IE
- Prosthetic valves/material (conduits, shunts)
- Cardiac transplant recipients with valvulopathy
- RHD in indigenous Australians
What is this ecg of and what is the mx?
= VT
Mx
Lidocaine, amiodarone, procainamide
Propranolol
Cardioversion
what is this? what is mx?
Sick sinus syndrome
A disease characterized by abnormal sinus node functioning with resultant bradycardia and cardiac insufficiency.
Sx result from decr CO and decr end-organ perfusion
Syncope, pre-syncope
Dizziness
Palpiatations
Mx:
Severe bradycardia = atropine
Pacing = temporary followed by permanent
Remove causative agents (ie digoxin, Ca blockers, beta blockers)
what is this? what is mx?
Long QT syndrome
BEta blockers
what is this? what is mx?
SVT
Vagal maneuver
IV adenosine
Oral flecainide
Cardioversion if acutely ill
Do NOT give digoxin
What is this?
what is mx?
Atrial flutter (saw tooth, rate >300, variable blocks)
Digoxin, sotalol
Cardioversion
What do you NOT give in SVT as mx?
Digoxin
VACTERL association
What does it stand for?
Need a minimum of 3 of the following:
Vertebral anomalies
Anal malformations (imperf)
Cardiac (TOF most common, VSD, ASD, Truncus, TGA)
Tracheo-esophageal fistula
Renal - incomplete formation of 1 or both kidneys +/- single umbilical artery
Limb anomalies - poly/syndactyly, displaced or radial thumb
Cardiac rhabdomyosarcoma is assoc w what syndrome?
Tuberous sclerosis
What condition commonly causes congenital heart block?
What would you test for antenatally?
maternal SLE (Lupus) - maternal ab against connective tissue crosses placenta and targets neonatal myocardium
-> test for ENA = extractable nuclear antigens (Anti-rho and anti-La )
maternal Sjogrens
tx - medical is atropine or isoproterenol; pacemaker
Forms of WPW
- Sinus rhythm (2)
- Tachyarrhthmia
- Refers to the presence of a congenital accessory pathway (called the Bundle of Kent, or atrioventricular bypass tract) and episodes of tachyarrhythmias
- Sinus rhythm:
- Type A: positive delta wave in all precordial leads with prominent R > 1 in V1
- Type B: prominent S wave in V1 and negative delta wave in leads V1 and V2
- AVRT can be orthodromic or antidromic conduction
- orthodromic: narrow QRS, no discernible p waves, indistinguishable from AV-nodal re-entry tachycardia (AVNRT)
- antidromic: wide QRS, resembles VT (which is less common in children)
What is this?
Type A sinus rhythm pattern WPW
- Sinus rhythm with a very short PR interval (< 120 ms)
- Broad QRS complexes with a slurred upstroke to the QRS complex — the delta wave
- Dominant R wave in V1 — this pattern is known as “Type A” WPW and is associated with a left-sided accessory pathway
what is this?
Type B WPW SR
- Negative delta waves in leads III and aVF simulate the Q waves of prior inferior MI (= pseudo-infarction pattern)
What is this?
Orthodromic atrioventricular re-entry tachycardia (AVRT), WPW
- Regular, narrow complex tachycardia at 225 bpm
- No discernible P-waves
- The QRS complexes are narrow because impulses are being transmitted in an orthodromic direction (A -> V) via the AV node
- This rhythm is indistinguishable from AV-nodal re-entry tachycardia (AVNRT)
Antidromic AVRT in a 5-year old boy with WPW:
- There is a regular, broad complex tachycardia at ~280 bpm; this would be very difficult to distinguish from VT
- However, given the child’s age, VT is very unlikely: > 95% of broad complex tachycardias in children are actually some form of SVT with aberrancy
Atrial fibrillation in a patient with WPW:
- Rapid, irregular, broad complex tachycardia (overall rate ~ 200 bpm) with a LBBB morphology (dominant S wave in V1)
- This could easily be mistaken for AF with LBBB
- However, the morphology is not typical of LBBB, the rate is too rapid (up to 300 bpm in places, i.e. too rapid to be conducted via the AV node) and there is a subtle beat-to-beat variation in the QRS width which is more typical of WPW (LBBB usually has fixed width QRS complexes)
- Although there is a broad complex tachycardia (HR > 100, QRS > 120), the appearance in V1 is more suggestive of SVT with aberrancy, given that the the complexes are not that broad (< 160 ms) and the right rabbit ear is taller than the left.
- However, on closer inspection there are signs of AV dissociation, with superimposed P waves visible in V1
- Also, the presence of a northwest axis and an R/S ratio < 1 in V6 (tiny R wave, deep S wave) indicate that this is VT
- This patient had a completely different QRS axis and morphology on his baseline ECG.
what are the precordial chest leads
v1-6, placed on pt’s chest
VAD (ventricular assist devices)
A Ventricular Assist Device (VAD) is a mechanical pump used to provide adequate cardiac output when heart failure is resistant to medical therapy (assists ventricles in pumping blood to the body)
used for patients w ventricular dysfunction due to an acute but potentially reversible process (ex: acute myocarditis)
CI: biventricular dysfunction OR pulmonary HTN, active infection (sepsis)
Cardiac cycle
What does the 4th heart sound represent?
“atrial gallop,” occurs just before S1 when the atria contract to force blood into the left ventricle.
Note- normally it is inaudible, only occurs with noncompliant L ventricle
What does the 3rd heart sound represent?
“ventricular gallop,” occurs just after S2 when the mitral valve opens, allowing passive filling of the left ventricle
= rapid ventricular filling
what does the 2nd heart sound represent?
Closure of aortic and pulmonary valves = isovolumetric relaxation
physiological splitting occurs during inspiration (aortic valve closes first, followed by delay in closure of pulmonary valve)
paradoxical splitting occurs during expiration and can be caused by anything that delays the closure of the aortic valve including AS, HOCM or in the presence of a LBBB
A fixed split S2 (ie during inspiration AND expiration) is pathognomonic for the presence of an ASD
what does the 1st heart sound represent?
what causes splitting of 1st heart sound?
closing of the mitral and tricuspid valves = isovolumetric contraction
RBBB or PVCs can cause splitting of S1 (or can be physiological in 40-70% of ppl)
When does a fixed split S2 occur?
ASD
when does paradoxical splitting of S2 occur?
AS, HOCM or in the presence of a LBBB.
Mean HR for the following age groups
- 1st week of life
- 1-2 months
- 5-7 years
- 1st week of life: 125
- 1-2 months: 150
- 5-7 years: 100
RAD =?
LAD=?
- RAD = RVH
- LAD = not LVH. Abnormal activation of L muscle mass/abnormal position of conduction system
ex: tricuspid atresia, complete AVSD, primum ASD, double outlet R ventricle, HOCM, Noonan syndrome associated PVS or HOCM
How to calculate ECG rate using big squares
Divide number of large squares between QRS into 300
(note - rhythm must be regular)
In which leads should p wave be upright in normal sinus rhythm?
Leads I and aVF
Post covid19 inflammatory disease - potential cardiac changes
Conduction or heart block abnormalities
Coronary artery dilatation (Kawasai like illness)
Elevated troponin, BNP, ventriclar dysfunction
What CHD repair is assoc w RBBB and why?
TOF repair
RBBB after transatrial repair of tetralogy of Fallot is usually produced by infundibular resection, but not by VSD closure, and is associated with delayed activation of the pulmonary outflow tract and base of the right ventricle which results from damage to portions of the right ventricular conduction system.
what is this ?
LBBB → ‘William’
- QRS duration > 120ms
- Dominant S wave in V1
- Broad monophasic R wave in lateral leads (I, aVL, V5-6)
- Absence of Q waves in lateral leads
- Prolonged R wave peak time > 60ms in leads V5-6
Indicators of Atrial hypertrophy on ECG
- RAH
- LAH
Look at leads II and V1
Right atrial enlargement: p amplitude > 3mm in V1 and lead II (almost 1 small square)
LA enlargement: terminal deflection in V1 is wider and deeper than 1 small square
T wave evolution
>8 days - 8 years: inverted t waves in R precordium (V1-4)
- if not the case then RVH is present (IE upright T in V1 up to 8yrs is sign of RVH)
- After 8years get progressive change to upright T waves from L → R (V1 the last to change to upright, often persists inverted until late teens)
ECG changes hypokalaemia
U waves
Flattened T waves
ST depression
QT prolongation
ECG change for coarctation of aorta
RVH
Because in utero RV has been pushing blood through PDA into desc aorta → RVH
RVH
Axis: RAD for the patients age
Voltages:
- Tall R waves (greater than limits for patient’s age) in right-sided leads V4R and V1
- Deep S waves (greater than limits for patient’s age) in left-sided leads V5 and V6
R/S ratio: Abnormal R/S ratio in favour of RVH.
- Increased R/S ratio (greater than upper limits for child’s age) in V1-2
- R/S ratio < 1 in V6 (after one month of age)
Abnormal T waves: Upright T waves in V1 and V4R in children 3 days to 6 years (provided that T waves are normal elsewhere, i.e. upright in V6). This is evidence alone of significant RVH.
Abnormal Q waves: qR pattern in V1 (small Q wave, tall R wave) = highly specific for RVH.
LVH
Axis: LAD for the patients age (marked LAD is rare with LVH).
Voltages:
- Tall R waves in the left-sided leads V5 and V6 (greater than limits for patient’s age)
- Deep S waves in the right-sided leads V4R and V1 (greater than limits for patient’s age)
R/S ratio:
- Abnormal R/S ratio in favour of LV
- Decreased R/S ratio in V1-2 (less than upper limits for child’s age)
Abnormal Q waves in V5 and V6
Inverted T waves in I and aVL (LV strain pattern)
Normal conduction system
Arrhythmia mechanisms
Re-entry
- Mechanism: Uni-directional block
- Initiating trigger
- ex PAC, PVC
- inducible and over drivable by pacing
- Cardiovertable
Automatic
- NOT inducible or over drivable by pacing
- NOT cardiovertable
- Warm up/cool down (rate varies widely)
Triggered
- Mixed features
Tachycardia classifications (x2)
Supraventricular
→ Atrial
→ Atrioventricular
Ventricular -only require tissue below the bifurcation of bundle of his for their continuum
Atrial flutter
‘sawtooth’ pattern
Can be first presentation of chaotic atrial tachycardia
when should UNsynchonised shock (cardioversion/defib) be given?
VF
Some polymorphic VT
In other cases with a regular well defined QRS complex, should be SYNCHRONISED w the QRS complex to avoid inducing VF
In an unstable patient in whom you are doing advanced life support, what is the dose of defibrillation for a shockable rhythm?
4 J/kg
Then CPR for 2 min then assess rhythm
Monomorphic VT
VF
ECG of AVSD
Features:
RBBB
Left axis
Peaked P waves (right atrial hypertrophy) Prolonged PR interval (prolongation of the atrioventricular conduction time)
RVH (or Biventricular hypertrophy)
what is torsades de pointes
what are possible causes
It is a specific form of PVT occurring in the context of QT prolongation — it has a characteristic morphology in which the QRS complexes “twist” around the isoelectric line.
- For TdP to be diagnosed, the patient must have evidence of both PVT and QT prolongation
Causes
- Drug-induced
- Electrolyte abnormalities (Low K or Mg)
- Congenital long QT syndrome.
Torsades de pointes
What is the most common cyanotic congenital heart lesion and what is the prevalence?
TOF
0.7/1000
Treatment of ‘Tet spells’
- Oxygen (acts as a pulmonary vasodilator and a systemic vasoconstrictor, though maybe limited effect as primary problem is reduced pulmonary blood flow) - high flow via mask
- Squat position (knee-chest)
- Increases systemic venous return and thus pulmonary blood flow
- If not getting better
- Morphine (to suppress the respiratory centre and abolish hyperpnoea)
- IV beta blocker (propranolol)
- Relaxation of the RVOT with improved pulmonary blood flow
- Reduces the frequency/severity of spells (but usually surgical referral is required at this stage)
- Bicarb if acidotic
Physiology of test spells
- Any event that ↓ SVR suddenly (i.e. crying, defecation, tachycardia, hypovolemia or activity) produces a large right to left shunt that may initiate a hypoxic spell as pulmonary blood flow reduces
- The resulting drop in Pa02 and PaCO2 and reduced pH stimulate respiratory centres causing hyperpnoea
- This increases venous return to the RV which causes further 02 desaturation, and repeats the cycle
- You see worsening cyanosis and disappearance of the pulmonary stenosis murmur
- The baseline arterial sats (75-80%) are the best indicator of whether cyanotic episodes while crying are actually Tet spells
- May be worse in children with mild cyanosis (aren’t used to hypoxemia)
Physiology of cardiac muscle contraction
Plateau in myocyte AP allows INFLUX OF Ca from SR (=depolisation) → stimulates muscle contraction
- extracellular Ca enters via L-type Ca channels
- Higher intracellular Ca triggers release of more Ca from SR through ryanodine receptors (=Ca induced Ca release)
- Ca attaches to troponin C → tropomyosin moves → actin-myosin cross bridges form → contraction
Cross bridges last as long as Ca occupies tropninin
- tension in proportional to intracellular Ca concentration
IC Ca is removed (back into SR) to induce relaxation via:
- Ca ATPase
- Na/Ca ATP exchanger
Calcium-induced calcium release from the sarcoplasmic reticulum must occur under normal excitation-contraction coupling to cause contraction.
S2
- what causes pathological splitting?
- What causes paradoxical splitting?
Pathological splitting is caused by prolonged opening/delayed closure of pulmonary valve
- Pulm stenosis (R→L shunt)
- RBBB (delayed RV contraction → RV emptying → delayed pulm valve closure)
- ASD (RV volume overload → delayed pulm valve closure) - note this is characteristically ‘fixed splitting’ ie in insp AND exp
Paradoxical (splitting on expiration)
- severe AS
- HOCM
- LBBB
Truncus arteriosis
What is it/why does it occur
Presentation
During fetal development, the primitive truncus does not divide into the pulmonary artery and aorta, instead resulting in a single, large, arterial trunk that overlies a large, malalignment type ventricular septal defect.
Blood mixing occurs in ventricles and enters pulmonary and systemic circulation
Sx:
Mild cyanosis and symptoms and signs of congestive heart failure (eg, tachypnea, poor feeding, diaphoresis, enlarged liver) in the first few weeks of life.
- Hyperdynamic precordium
- Increased pulse pressure with bounding pulses
- Loud and single 2nd heart sound (S2), and an ejection click.
- A grade 2 to 4/6 systolic murmur is audible along the left sternal border (see table Heart Murmur Intensity).
Truncus arteriosis
What conditions is it associated with?
33% - CATCH 22
33% - 22q11 deletion/Di George (conotruncal defect)
Pericarditis
ECG features widespread STE and PR depression with reciprocal changes in aVR (occurs during the first two weeks)
Mx of Hypoplastic L heart
- Prostin to keep duct open
- Norwood procedure - first few weeks of life with aim to make the RV the player to pump systemic blood around body (Join aorta to RV, close PDA, make ASD bigger and create Blaylock-Taussig-Thomas shunt to shunt blood from aorta to lungs)
- Glenn procedure - 4-6mo old (remove BT shunt and disconnect SVC and reconnect directly to PA)
- Fontan procedure - 18-36mo (disconnect IVC and reconnect directly to PA so all systemic blood now goes directly to lungs)
Indications for Glenn Procedure and Fontan procedure
A
Hypoplastic left heart syndrome (no LV outflow)
Double outlet right ventricle (both aorta and PA connected to RV, no LV outflow)
Tricuspid atresia (no RV/PA outflow)
RV strain/hypertrophy pattern in a child (ECG)
TALL R wave in V1
Deep S wave in V6
Upright T-waves in V1 (this is abnormal in children age 8days -8yo, should be inverted!)
LV strain/hypertrophy pattern
Deep S wave in V1 (daggers like LBBB)
Tall R wave in V6
Inverted T-waves in lead I and IVL
LV strain/hypertrophy pattern
Deep S wave in V1 (daggers like LBBB)
Tall R wave in V6
Inverted T-waves in lead I and IVL
what is the lower limit cutoff for Qp:Qs for large shunt
Qp:Qs > 2:1 indicates large L→R shunt
what is ‘severe pulmonary hTN’ in woods units
Woods units > 12
Atrial tachycardia.
- ‘incessant’ AT = rare chronic arrhythmia in children and young adults. Can be difficult to manage
- Rate ~ 100 - >200 beats/min.
- Often resembles sinus tachycardia.
- narrow complex tachycardia
- Each QRS complex is preceded by an abnormal P wave
- p wave morphology is consistent throughout
- Diagnosis is important as it may lead to dilated cardiomyopathy if and left ventricular dysfunction if not properly managed
- First line digoxin -> beta blocker -> class 1 antiarrhythmic
Mumur of VSD
Systolic murmur loudest at the lower left sternal edge
Large/Severe VSDs are often accompanied on auscultation by a mid diastolic rumble indicating functional mitral valve stenosis
The magnitude of L-R shunting in an ASD is most influenced by what?
The magnitude of the left-to-right shunt is most influenced by the relative right and left ventricular compliances, with changes in the right ventricular compliance having the dominant effect. The relative vascular resistance in the pulmonary and systemic circulation also contribute to a lesser extent.
In the newborn period high PVR is accompanied by a relatively thick, poorly compliant RV. During this period flow may be bidirectional with minimal net flow through the defect. Throughout infancy, PVR drops and the increasingly complicant RV is able to accept more blood volume, resulting in increased L to R shunting through the atrial shunt.
What heart defect is associated with NF1?
Pulmonary valve stenosis in 50%
Less commonly: aortic stenosis, aortic coarctation, atrial septal defects (ASD), ventricular septal defects (VSD), and hypertrophic cardiomyopathy (HCM)
most common heart defect assoc w Alagille syndrome
Peripheral pulmonary stenosis
Most common heart defects assoc w Noonan synrome
Valvular pulmonary stenosis
HOCM
most common heart defects in VACTERL
VSD is #1
ASD
TOF
Most common heart defect Williams Syndrome
supravalvular aortic stenosis (70% of cases)
Most common heart defect w DMD
Dilated cardiomyopathy
Cardiac dysfunction is a frequent manifestation of Duchenne muscular dystrophy and a common cause of death for individuals with this condition. Early diastolic dysfunction and focal fibrosis proceed to dilated cardiomyopathy, complicated by heart failure and arrhythmia in most patients
Most common heart defect w DMD
Dilated cardiomyopathy
Cardiac dysfunction is a frequent manifestation of Duchenne muscular dystrophy and a common cause of death for individuals with this condition. Early diastolic dysfunction and focal fibrosis proceed to dilated cardiomyopathy, complicated by heart failure and arrhythmia in most patients
What is this?
Clinical significance?
PVCs
Usually benign except in cases of prolonged QTc → can lead to torsades de pointes, or in case of WPW can trigger tachydysrhythmias
Premature atrial ectopics
BEnign except in case of WPW/ischaemia etc when can trigger re-entrant tachydysrhythmias
What is this?
Premature junctional complex
Usually benign
PJCs have the following features:
- Narrow QRS complex, either (1) without a preceding P wave or (2) with a retrograde P wave which may appear before, during, or after the QRS complex. If before, there is a short PR interval of < 120 ms and the “retrograde” P waves are usually inverted in leads II, III and aVF.
- Occurs sooner than would be expected for the next sinus impulse.
- Followed by a compensatory pause.
- PJCs that arrive early in the cycle may be conducted aberrantly, most commonly with a RBBB morphology.
