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
Q waves - what is abnormal on ECG?
Torsades de pointes
Can be sign of underlying long QT syndrome
What does this ECG show?
Ventricular tachycardia
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
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
ECG findings of pericarditis
ST elevation (saddle)
T wave inversion
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 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.
Cardiac cycle
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
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
ECG changes hypokalaemia
U waves
Flattened T waves
ST depression
QT prolongation
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
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
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
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).
Pericarditis
ECG features widespread STE and PR depression with reciprocal changes in aVR (occurs during the first two weeks)
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
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.
