Cardiology Flashcards
Why are shunts in place in fetal circulation?
Blood needs to go via placenta to collect oxygen and nutrients, dispose of carbon dioxide and lactate via the mother.
Blood does not pass through the pulmonary circulation.
What are the 3 fetal shunts present?
Ductus venosus - umbilical vein to inferior vena cava, bypassing the liver
Foramen ovale - right atrium to left atrium, bypassing the right ventricle and pulmonary circulation
Ductus arteriosus - pulmonary artery with aortia, bypass pulmonary circulation
What happens to fetal circulation at birth?
The first breath expands the alveoli, decreasing pulmonary vascular resistance.
Decrease in resistance causes fall in pressure in right atrium.
LA pressure now greater than the right atrium, squashing the atrial septum and closure of foramen ovale.
Then becomes sealed shut and becomes fossa ovalis.
Increased blood oxygenation causes drop in PGs - which are needed to keep ductus arteriosus open so this shuts - becomes ligamentum arteriosum.
Ductus venosus stops functioning because the umbilical cord is clamped and there is no flow in the umbilical veins - becomes ligamentum venosum.
Describe the path of the fetal circulation
Oxygenated blood from the placenta enters umbilical vein, bypasses liver by DV
Then enters vena cava to the heart, bypasses pulmonary circulation via FO into the left atrium, blood that does enter the pulmonary artery passes through DA to re-enter systemic circulation
Deoxygenated blood returns to placenta via umbilical arteries that branch off from internal iliac.
What are the acyanotic heart defects?
Left to Right shunts
ASD VSD Coarctation of the Aorta Patent Ductus Arteriosus Pulmonary stenosis
How do acyanotic defects present?
Most are picked up on antenatal screening
Asymptomatic mostly
Possibly
Fail to thrive
Resp infections
Heart failure
Why can you see heart failure with acyanotic heart defects?
Increased pressure in pulmonary circulation
What is Eisenmenger’s syndrome?
L –> R shunt swap to R –> L if pulmonary pressure rise to exceed systemic pressure
How are acyanotic heart defects commonly investigated?
Echo - flow and anatomy
ECG - identity cardiomegaly or pulmonary hypertension
Cardiac catheter - if severe
How would you see cardiomegaly or pulmonary hypertension on ECG?
Commonly Left Ventricular hypertrophy - lead I increase, lead III invert
Right ventricular hypertrophy, right axis deviation, p pulmonale, tall R in V1, right ventricular strain
How are acyanotic heart defects managed in the general term?
Loop diuretics if heart failure
Surgical closure of defect
What are the risk factors for developing an acyanotic heart defect?
Family history
Maternal smoking/toxins/infection/diabetes
Genetic conditions - Down’s
What are innocent murmurs?
Flow murmurs, very common in children
Caused by fast blood flow through various areas of the heart during systole
What are the features of innocent murmurs?
Soft Short Systolic Symptomless Situation dependent - gets quieter with standing, or only appears when unwell
When may a heart murmur in a child need to be investigated?
Murmur louder than 2/6 - soft heard in all positions no thrill
Diastolic murmurs
Louder on standing
Other symptoms such as failure to thrive, feeding difficulty, cyanosis or shortness of breath
What are the key investigations to establish the cause of a murmur?
ECG
CXR
Echo
What are the differentials for a pan-systolic murmur?
Mitral regurgitation
Tricuspid regurgitation
Ventricular septal defect heard at the left lower sternal border
What are the differentials of ejection-systolic murmurs?
Aortic stenosis
Pulmonary stenosis
Hypertrophic obstructive cardiomyopathy heard loudest at the fourth intercostal space on the left sternal border
What causes splitting of the second heart sound?
Inspiration - diaphragm pulls lungs and heart open, creating negative intra-thoracic pressure
This causes the right side of heart to fill faster, increased volume in right ventricle means it takes longer to empty - delay in pulmonary valve to close.
Pulmonary valve closes later than aortic valve - split sound.
What murmur is heard in an atrial septal defect?
Mid-systolic crescendo-decrescendo murmur
Loudest at upper left sternal border
Fixed split second heart sound
What murmur is heard in PDA?
May not cause any abnormal heart sounds
More significant - normal first heart sound, and continuous crescendo-decrescendo murmur during second heart sound
What murmur is heard in tetralogy of fallot?
Arises from pulmonary stenosis
Ejection systolic murmur
Loudest at pulmonary area - second intercostal space, left sternal border
Why do patients with transposition of the great arteries always have cyanosis?
Because the right side of the heart pumps blood directly into the aorta and systemic circulation
What is the most common cause of common mixing? (breathless and blue)
Atrioventricular septal defect
What causes a child to be asymptomatic with a murmur?
Innocent murmur
Outflow obstruction in a well child - pulmonary stenosis or aortic stenosis
What are the causes of a collapsed child with shock - outflow obstruction in a sick neonate?
Coarctation of the aorta
What cardiac abnormalities result from rubella infection?
Peripheral pulmonary stenosis
PDA
What chromosomal abnormalities can cause cardiac abnormalities?
Down’s - ASD, VSD
Edwards
Patau
Turner’s - aortic valve stenosis, coarctation
Noonan syndrome - hypertrophic cardiomyopathy, ASD, pulmonary valve stenosis
What is the presentation of congenital heart disease?
Antenatal cardiac USS diagnosis Detection of a heart murmur Heart failure Shock Cyanosis
Why might a child with a potential shunt have no symptoms or murmur at birth?
Pulmonary vascular resistance is still high
What are the symptoms and signs of heart failure?
Symptoms: Breathlessness Sweating Poor feeding Recurrent chest infections
Signs Poor weight gain Tachypnoea Tachycardia Heart murmur, gallop rhythm Enlarged heart Hepatomegaly Cool peripheries
What are the causes of heart failure?
Neonates: Hypoplastic left heart syndrome Critical aortic valve stenosis Severe coarctation of aorta Interruption of aortic arch
Infants - high pulmonary blood flow
Ventricular septal defect
Atrioventricular septal defect
Large persistent ductus arteriosus
Older children and adolescents
Eisenmenger syndrome - right heart failure
Rheumatic heart disease
Cardiomyopathy
What is the most likely cause of heart failure in the first week of life?
Left heart obstruction e.g. coarctation
If the lesion is v severe, then arterial perfusion may be duct-dependent systemic circulation.
What is the most likely cause of heart failure after the first week of life?
Left to right shunt
During subsequent weeks, pulmonary vascular resistance falls meaning progressive left to right shunt causing pulmonary oedema and breathlessness
If left untreated will develop Eisenmenger syndrome and shunt now right to left, pt is blue.
What are the causes of cyanosis in a newborn infant with respiratory distress? >60 breaths/min
Cardiac disorders - cyanotic congenital heart disease
Respiratory disorders e.g. surfactant def, meconium aspiration
PPHN persistent pulmonary hypertension of the newborn; failure of pulmonary vascular resistance to fall after birth
Infection - sepsis from Group B strep
Metabolic disease - acidosis and shock
When does congenital heart disease present with shock?
When duct closes in severe left heart obstruction
What are examples of left to right shunts?
Atrial septal defects
Ventricular septal defects
Persistent ductus arteriosus
What is an ASD?
Occurs when the septum between left and right atrium is not formed completely
Pressure in LA is greater so oxygenated blood from LA forced through ASD to RA, so acyanotic
What is the pathophysiology of ASD?
Two separate endocardial cushions form the atrial septum. Space between is foramen ovale. Does not close.
What are the five types of ASD?
Patent foramen ovale Ostium secundum defect Ostium primum defect Sinus venosus defect Coronary sinus defect
What causes ostium secundum defect?
Incomplete occlusion of ostium secundum by septum secundum, or septum primum reabsorbed too much
What causes ostium primum?
Septum primum fails to fuse with endocardial cushions
What are the 2 types of ostium primum defects?
Complete AVSD
Partial AVSD - just the ostium primum, intact ventricular septum
What are the types of sinus venosus defects?
Superior - superior vena cava opening runs on top of oval fossa
Inferior
What are the risk factors for ASDs?
Autosomal dominance with ostium secundum Family history Maternal smoking 1st trimester Maternal diabetes Maternal rubella Maternal drug use e.g. cocaine and alcohol
What are the symptoms of large ASDs in paeds?
Vast majority smaller ones are asymptomatic
Tachypnoea
Poor weight gain
Recurrent chest infections
What are the symptoms of untreated large ASDs in adults?
Exercise intolerance Palpitations Recurrent chest infections Fatigue Syncope
What is heard on auscultation in ASD?
Murmur - soft, systolic ejection, best heard over pulmonary region 2nd ICS
Wide fixed split S2
Diastolic rumble in lower left sternal edge if large
What are the differentials for ASD?
Atrioventricular septal defect
Ventricular septal defect
Innocent murmur
Pulmonary stenosis murmur - more turbulent
What are the investigations for ASD?
Bedside:
ECG usually normal
In large ASD - tall P wave, right bundle branch block, right axis deviation
Imaging:
Transthoracic echo - provides info on size of ASD and direction of flow
Cardiac MRI and CT (not usually imaging of choice due to radiation)
MRI can measure blood flow ratio
CXR can show cardiomegaly, usually normal in children with small shunts
What is the initial management for ASD?
Conservative:
If <5mm, spontaneous closure should occur within 12 months of birth
In adults, if no signs of right heart failure and small defect, echo every 2-3 yrs
If arrhythmia - control rhythm with drugs and anticoagulate before surgical treatment
Medical:
With heart failure, diuretics
Endocarditis prophylaxis not currently required
What is the definitive management for ASD?
Surgical closure >1cm
Percutaneously via transcatheter or open chest using bypass
What are the complications of percutaneous closure of ASD?
Arrhythmias
Atrioventricular block
Thromboembolism - VTE aspirin
What are the indications for surgical closure of an ASD?
TIA/stroke
Ostium primum defects
Sinus venous defects
Coronary sinus defects
What are the complications of untreated large ASDs?
Arrhythmias - caused by atrial stretch leading to abnormal foci developing Pulmonary hypertension Eisenmenger syndrome Cyanosis if Eisenmenger Peripheral oedema TIA/stroke
What is the presentation of Eisenmenger syndrome?
Chronic cyanosis Exertional dyspnoea Syncope Increased risk of infections Increased pulmonary vascular resistance
Give 4 causes of acyanotic heart disease?
- atrial +/- ventricular septal defects
- PDA
- aortic stenosis
- pulmonary valve stenosis
- coarctation of the aorta
Give 6 differentials for a blue baby
central: CO poisioning, sepsis, polycythameia, congenital heart disease
resp: penumonia, pneumonthorax, ARDS, pulmonary atresia, foreign body inhalation
Neuro: asphyxia, seizures, sedatives
What could cause a systolic murmur in a child? (4)
- non pathological, innocent murmur
- VSD
- outflow tract obstruction
- mitral regurg
- PDA
what could cause a diastolic murmur in a child? (3)
- venous hum (non pathological)
- Aortic regurg
- Atrial septal defect
What is tetralogy of fallot?
- VSD + pulmonary stenosis
- leads to ventricular hypertrophy and overriding aorta
- blood flows mostly into aorta and baby relies on PDA to get blood to lungs
How will a child with a mild (“pink”) TOF present?
- asymptomatic at birth as plenty blood can still get out pulmonary artery
- heart failure will progress as they grow and the heart cannt meet demands
- usually presents age 1-3 with odema, SOB, fatigue, failure to thrive, basal crackles, hepatomegaly, murmur
how may a moderate- severe TOF present?
- moderate presents with resp distress or cyanosis in first few weeks as the ductus arteriosus starts to close
- severe TOFs with pulmonary atresia is usually detected antenatally, if not theyll present with resp distress/ cyanosis within the first few hrs of life
What are the risk factors for TOF?
Males
1st degree family history
Teratogens - alcohol, warfarin, trimethadione (antiepileptic drug used in treatment resistant epilepsy)
Genetics
CHARGE syndrome
Di George syndrome
Associated congenital defects
What is perimembranous VSD?
When VSD involves parts of membranous and muscular septum
Commonest type associated with TOF
Why might a patient be acyanotic with VSD?
Significant size VSD, causes systolic pressures between the ventricles to equalise
In mild TOF, the left ventricular pressures remain higher than the right, so blood shunts from left to right
Why might a patient be cyanotic with VSD?
More severe disease
Increased right ventricular pressure - secondary to PS
The shunt direction reverses from right to left allowing mixture of deoxygenated and oxygenated blood
so cyanotic
Where is the most common site of pulmonary stenosis?
Infundibular septum
right ventricular outflow tract
What occurs in TOF as a result of pulmonary stenosis?
Impaired flow of deoxygenated blood into main pulmonary artery
May be severe enough to cause intermittent RVOT obstruction
Causes hypoxic episodes - tet spells
What is the boot sign in TOF?
Seen on CXR
Develops in utero
Hypertrophy of the right ventricle due to high pressures to pump deoxygenated blood through the RVOTO
What is the presentation of extreme TOF?
Pulmonary atresia or
Absent pulmonary valves
These are true duct dependent lesions - only way deoxygenated blood can flow into lungs is through patent ductus arteriosus
If not discovered in antenatal scans, presents in first few hours of life with resp distress, cyanosis
What are tet spells?
Hypoxic spells
Peak age of incidence between 2-4 months of life
Paroxysm of hyperpnoea - rapid deep respirations, right to left shunting so CO2 accumulates driving the central resp centre
Irritability - prolonged, unsettled crying
Increasing cyanosis
What can be found in TOF on examination?
Central cyanosis, clubbing
Palpation - thrill or heave (RVH)
Auscultation
Loud single S2 - due to closure of aortic valve in diastole
Pansystolic murmur - smaller the VSD the louder the murmur
Ejection click due to presence of dilated aorta
Continuous machinery murmur in the presence of PDA with extreme forms of TOF, especially those on PG infusion
Signs of congestive heart failure - sweating, pallor, tachycardia, hepatosplenomegaly, generalised oedema, bilateral basal crackles or gallop rhythm
What are the differentials for TOF?
Other cyanotic CHD
- critical PS, transposition of great arteries, hypoplastic left heart syndrome
Isolated VSD - does not cause cyanosis as shunt is left to right, unless there is Eisemenger syndrome
Sepsis - any resp distress and hypoxia
What are the investigations for TOF?
Bedside - ECG showing right axis deviation, RVH
Bloods - microarray if genetic syndromes suspected
Radiological -
CXR - boot shaped heart, reduced pulmonary vascular marking (decrease pulmonary blood flow)
Echo
Cardiac CT angiogram
Cardiac MRI
Interventional radiology with cardiac catheter to measure haemodynamics
What is the medical management of TOF?
Squatting/knees to chest - helps venous return, increases systemic resistance
PG infusion - helps maintain PDA if more severe form.
Either alprostadil or dinoprostone
Beta-blockers - propranolol used in tet spells, reduces the heart rate
Morphine - reduces resp drive, reduces hyperpnoea
Saline 0.9% bolus
Used in tet spells as a volume expander to increase pulmonary blood flow
What is the surgical management of TOF?
Palliative
Transcatheter RVOT stent to relieve RVOTO, buys time until child is bigger
Modified Blalock-Taussig shunt mimics as PDA, increases pulmonary blood flow before definitive repair
Insertion of RV to PA conduit or PA banding
Definitive repair
Cardiopulmonary bypass via median sternotomy; RVOT resection, augmentation, VSD patch closure
What are the complications of TOF?
Polycythaemia Cerebral abscess Stroke Infective endocarditis Congestive cardiac failure Death - up to 25% in 1st year of life
Pulmonary regurgitation, arrhythmias, exercise intolerance, sudden death even post corrective surgery
What is required for follow up for TOF?
Regular ECG
ECHO
Cardiopulmonary exercise testing in exercise tolerance
What are the side effects of prostaglandin infusions?
- apnoeas
- bradycardia
- hypotension
What is AVSD?
Defect of atrioventricular septum and abnormalities of the AV valves - mitral and tricuspid valves
What are the types of AVSDs?
Partial AVSD
Complete AVSD
What is the epidemiology of AVSD?
Strong association with Down’s
Complete can occur with heterotaxy syndromes - abnormal arrangement of internal thoracic-abdominal organs across axis of body
What is the aetiology of AVSD?
Normally primitive AV canal connects atria to ventricles
At 4-5 wks gestation, superior and inferior endocardial cushions fuse
Defects due to failure of endocardial cushions to fuse correctly
Complete failure to fuse causes an ASD (primum atrial septal defect) and VSD (ventricular septal defect) and a single common atrio ventricular valve
What occurs in complete AVSD?
Increased shunting of blood from left to right side of heart
Pulmonary vascular resistance decreases normally over first 6 weeks, patient develops large left to right shunt
Causes excessive pulmonary blood flow, heart failure, elevated pulmonary vascular resistance
Incompetent abnormal valve, regurgitation
What occurs in partial AVSD?
Left to right shunting
Volume overload of right atrium and right ventricle
Pulmonary artery pressures remain normal
So symptoms may be minimal
What structural changes may occur in AVSDs?
Increased distance between aorta and apex of the heart
Results in elongation of left ventricular outflow tract
Aortic valve displaced anterosuperior - goose neck deformity
What are the clinical features of AVSD?
Tachypnoea Tachycardia Poor feeding Sweating Failure to thrive - due to excessive metabolic requirements and poor calorie intake
What can be observed on examination in AVSD?
General
Inspection
Palpation
Auscultation
Undernourished child
May have characteristics of Down’s
Congestive HF - hepatomegaly, gallop rhythm, oedema, crackles
Inspection - pallor, Harrison grooves
Palpation -
Hyperactive precordium
Prominent systolic heave
Palpable apical thrill
Auscultation Complete: Accentuated S1, loud S2 Ejection systolic murmur Mid-diastolic murmur Holosystolic murmur
Partial: Wide and fixed splitting SW, does not change w inspiration Ejection systolic murmur Mid-diastolic murmur Holosystolic murmur
What are some differentials for AVSD?
Isolated atrial septal defect
Isolated ventricular septal defect
Patent ductus arteriosus - machinery murmur throughout systole and diastole
Paediatric heart failure
Sepsis
Causes of poor weight gain, failure to thrive e.g. malabsorption, nutritional deficiencies
What are the investigations for AVSD?
Bloods - blood sample for karyotyping e.g. for Down’s
ECG - complete AVSD Superior QRS axis Prolonged PR interval due to atrial enlargement P wave morphology Right ventricular hypertrophy
Radiology - CXR cardiomegaly, pulmonary artery prominent
ECHO
What is the medical management for AVSD?
For symptomatic relief of heart failure, buys time for child to grow, gain optimum weight before corrective surgery
Diuretics - furosemide loop diuretic to relieve pulmonary congestion, reduces preload
Can cause hypokalaemia so spironolactone added
ACEi - captopril, reduces systemic vascular resistance, reduces afterload reduction, more blood through left ventricular outflow tract and less in left to right shunt
Can increase K so stop spironolactone with this
Digoxin - acts on cardiac muscle, increases systolic contraction, increases inotropy without increasing oxygen consumption, slow HR
Adequate caloric intake
High energy formula feeds, NG tube if cannot tolerate oral
What is the usual approach for management of heart failure with an AVSD?
Start with diuretic and afterload reducing agent
Digoxin later added if further improvement needed
What is the surgical management of AVSD?
Complete AVSD needs corrective surgery; performed prior to development of irreversible pulmonary vascular obstructive disease, median age of surgery 3-6 months
Palliative surgery -
Pulmonary artery banding, decreases diameter and reduces the pulmonary blood flow to relieve symptoms e.g. if premature, low birth weight, allow time to mature
Corrective surgery -
Via median sternotomy under cardiopulmonary bypass
Closure of atrial and ventricular communications, construct two separate and competent AV valves from available leaflet tissue
Single patch to close ASD and VSD, double patch, modified patch
What are the complications of untreated AVSD?
Failure to thrive Recurrent lower resp tract infections Congestive heart failure Pulmonary vascular disease Eisenmenger's syndrome
What complications may occur following AVSD surgical repair?
Left AV valve regurgitation, due to inadequate surgical reconstruction
Residual shunt
Arrhythmias
Sinus node dysfunction - results in bradycardia
Wound infection
What is a VSD?
Hole in the septum separating the left and right ventricles
Can occur as isolated lesion or alongside other CHDs
What occurs in a small VSD?
Restrictive VSD - blood flow through is minimal, so no significant increase in pulmonary blood flow
Asymptomatic
Why do most patients with VSD experience symptoms?
Due to increased flow of blood through pulmonary circulation
Pressure in left ventricle greater than right so shunting is from left to right
What symptoms are seen in a moderate-sized VSD?
Flow of blood through VSD is great enough to cause significant increase in blood flow through pulm circ.
Shunt occurs in systole, so blood pumped directly into pulm circ and does not affect right ventricle
Dilatation of left atrium and ventricle because receiving large vol of blood, so can cause heart failure
What symptoms are seen in large VSDs?
Significant amount of blood passing from left to right ventricle
Develop early heart failure and severe pulmonary HTN
Symptoms of cardiac failure evident after first few weeks of life
What are the risk factors for VSD?
Maternal diabetes uncontrolled during pregnancy
Maternal rubella infection during pregnancy
Alcohol fetal syndrome
Uncontrolled maternal phenylketonuria PKU
Family history
Down’s, trisomy 18 and 13
What are the clinical features of a small VSD?
Mild or no symptoms
Systolic murmur detected in routine examination
What are the clinical features of moderate VSD?
Babies may have excessive sweating, easily fatigued
Tachypnoea
Especially notable when feeding
Obvious by 2-3 months as pulmonary vascular resistance decreases, and increase in left to right shunting
What are the clinical features of large VSD?
Symptoms of congestive heart failure
SOB, problems feeding, developmental issues, freq chest infections
Eisenmenger’s syndrome can develop if large VSD left untreated - cyanosis
Intolerance to exercise, dizzy, chest pain, oedema, bluish complexion.
May have haemoptysis in severe cases.
What is seen on general inspection in VSD?
Undernourished - fatigue during feeding so undernourished
Sweat on forehead - due to increased sympathetic activity, compensatory mechanism for decreased cardiac output
Increased work of breathing - due to pulmonary congestion
Cyanotic
Clubbing due to long standing arterial desat, but may be too mild to cause bluish complexion
Tachypnoea - left sided heart failure
What is seen on palpation in VSD?
Palpate precordium, check peripheral pulses
Pulse rate - raised in congestive heart failure
Precordial palpation above where heartbeat felt; moving too much - hyperactive precordium, due to volume overload in left side of heart
Thrills - max intensity in lower left sternal border
What is heard on auscultation in VSD?
Systolic murmur between S1 and S2
It is found at lower left sternal border
High pitched uniform blowing sound
Either holosystolic/pansystolic extends all the way from S1-S2
Or early systolic ends in middle or early systole, occurs when there is lower than normal pressure difference on the sides of the defect
e.g. neonate with large VSD
Or can have a diastolic murmur due to increased blood flow through mitral valve, mitral stenosis
Apical rumble/humming sound
What are the differentials for VSD?
Mitral regurgitation
Tricuspid regurgitation
Atrial septal defect - murmur higher up, ejection systolic
Patent ductus. arteriosus
Pulmonary stenosis - ejection systolic murmur
Tetralogy of Fallot - symptoms more severe
What are the investigations for VSD?
Bedside - ECG
Left ventricular hypertrophy or bilateral vent hypertrophy
Bloods -
Sepsis screen, U&Es for kidney function prior tx with diuretics or ACEi
Microarray for genetics
Radiology - CXR - large VSDs cardiomegaly, pulmonary oedema, pleural effusion ECHO Cardiac CT MRI
Cardiac catheterisation helps with treatment
What is the medical management for VSDs?
If small and symptomatic be ok, but maintain good oral hygiene to prevent IE.
Won’t close the defect, but relieve symptoms to buy time.
Increased caloric density of feeds for weight gain, may need to be NG with CHF
Diuretics - furosemide, add spironolactone for K sparing
ACEi - reduce left to right shunt, reduce afterload
Discontinue spironolactone
Digoxin to treat CHF
Increases heart muscle strength, maintains normal rhythm
What is the surgical management of VSD?
If medium or large, or causing symptoms.
Surgical repair via median sternotomy and cardiopulmonary bypass, use of patch or stitches to close
Catheter less common as often not suitable, inserted via femoral artery, mesh
Hybrid - interventional cardiology
Palliative surgery with pulmonary artery banding and then full surgery later
When is surgical closure of VSD indicated?
Qp/Qs (pulmonary to systemic blood flow ratio) of 2.0 or more
What long term management if required for VSD?
Good dental hygiene to reduce risk of endocarditis
Avoid non medical procedures e.g. piercings and tattoos
Regular cardiac follow up
What are the complications of VSD if left untreated?
Congestive heart failure Growth failure Aortic valve regurgitation due to prolapse of valve Pulmonary vascular disease Freq chest infections Infective endocarditis Arrhythmias Sudden death
What are possible complications following surgical repair of VSD?
Permanent heart block requiring a pacemaker
Other arrhythmias
Wound infection
Reoperation of significant residual VSDs
What is the pathophysiology of a PDA?
Pressure in aorta is higher than that in pulmonary vessels, blood flows from aorta to pulmonary artery - left to right shunt.
So pressure in pulmonary vessels is raised, leads to pulmonary hypertension and right sided heart strain
So leads to right ventricular hypertrophy
Then increased blood flow through pulmonary vessels and returning to left side leads to left ventricular hypertrophy
What is the presentation of a PDA?
SOB
Difficulty feeding
Poor weight gain
LRTI
Murmur if more severe
Normal S1 and continuous crescendo-decrescendo murmur that may continue during S2 making it hard to hear
How can a PDA be diagnosed?
ECHO
Use of doppler can assess size and characteristics of the left to right shunt
What is the management of PDA?
For premature very low birth weight infants. - prophylactic therapy with intravenous indomethacin - COX inhibition and reduction in prostaglandins
Acute treatment for premature infants - indomethacin or ibuprofen, surgical ligation
For term infants and children - percutaneous catheter device closure, diuretics furosemide
When does the PDA usually close?
Within first 48 hours of life
What are the risk factors of PDA?
Prematurity
Maternal rubella
Female sex
RDS
What are the diagnostic factors of PDA?
Presence of risk factors SOB Failure to thrive Exercise intolerance Widened pulse pressure Gibson machinery murmur Apnoea in premature infants
What are the investigations for PDA?
CXR
ECG
Echo
Cardiac catheterisation and angiography
What is coarctation of the aorta?
Congenital condition where there is narrowing of the aortic arch
Usually around the ductus arteriosus
What is the presentation of coarctation of the aorta?
In neonate - may only be weak femoral pulses
Four limb BP shows high BP in the limbs supplied from arteries coming before narrowing, and low in those afterwards
Systolic murmur below left clavicle and scapula
Tachypnoea
Increased work of breathing
Poor feeding
Grey and floppy baby
Left ventricular heave due to left ventricular hypertrophy
Underdeveloped left arm due to reduced flow to left subclavian
Underdeveloped legs
What are common diagnostic factors in coarctation of aorta?
HTN at young age, or resistant to treatment
Diminished lower extremity pulses
Differential upper and lower extremity BPs
Systolic ejection murmur
Male sex
Could have Turner’s, Di George
What are the risk factors for coarctation of aorta?
Male sex Young age Turner's Di George's Hypoplastic left heart Shone's complex PHACE syndrome
What are the investigations for coarctation of the aorta?
ECG, CXR, Echo
CT, MRI, cardiac catheterisation
What is the management of coarctation of the aorta?
Critical - maintenance of ductal patency with alprostadil to maintain DA and then surgical repair
If not critical - surgical repair better than transcatheter
What occurs in congenital aortic valve stenosis?
Born with narrow aortic valve; restricts blood flow from left ventricle into aorta
Aortic sinuses of Valsalva are the valve leaflets - can be a varied number of leaflets
What is the presentation of aortic valve stenosis?
Mild asymptomatic and an incidental murmur on exam
Significant - fatigue, SOB, dizziness, fainting.
Worse on exertion as outflow cannot keep up
Severe will present with heart failure within months
Ejection systolic murmur
Loudest in aortic area
Crescendo-decrescendo
Radiates to the carotids
Ejection click just before murmur
Palpable thrill
Slow rising pulse, narrow pulse
Acute collapse in neonatal period, or in an older child e.g. child with chest pain and exertion
What is the management of aortic valve stenosis?
Diagnosis by echo
Regular follow up with echo, ECG, exercise testing
Percutaneous balloon aortic valvoplasty
Surgical aortic valvotomy
Valve replacement
Ross procedure - disconnect pulmonary valve from right side, then insert valve replacement on pulmonary side
Moderate can monitor in clinic, monitor for endocarditis
Family screening for bicuspid aortic valve
What are the complications of aortic stenosis?
Left ventricular outflow obstruction Heart failure Ventricular arrhythmia Bacterial endocarditis Sudden death
What occurs in pulmonary valve stenosis?
Pulmonary valve consists of three leaflets; in PVS leaflets can develop abnormally, become thickened or fused.
So narrowed between right ventricle and pulmonary artery
What conditions are associated with pulmonary valve stenosis?
Tetralogy of Fallot
William syndrome
Noonan syndrome
Congenital rubella syndrome
What is the presentation of pulmonary stenosis?
Often completely asymptomatic, incidental finding
Symptoms of fatigue, SOB, dizziness and fainting
Ejection systolic murmur heard loudest at pulmonary area
Palpable thrill in pulmonary area
Right ventricular heave due to right ventricular hypertrophy
Raised JVP, giant a waves
Critical collapse in neonatal period when arterial duct closes
What is the management of pulmonary stenosis?
Can be an increased risk of endocarditis
Diagnosis with echo
Watching and waiting if mild pulmonary stenosis
Balloon valvuloplasty via venous catheter through femoral vena into inferior vena cava and right side of heart
Open heart surgery
What are the 5 Ts of cyanotic congenital heart disease?
Tetralogy of Fallot Transposition of Great Arteries Truncus arteriosus Total anomalous pulmonary venous return Tricuspid valve abnormalities and hypoplastic right heart syndrome
What is transposition of the great arteries?
Ventriculoarterial discordance
Aorta arises from the morphologic right ventricle and pulmonary artery from morphologic left ventricle
Potentially fatal parallel circulation
Deep hypoxaemia from lack of mixing, results in lactic acidosis and demise.
What is the classification of transposition of great arteries?
Dextro-TGA aorta from RV, PA from LV causes deoxygenated blood from right heart to be pumped immediately through aorta and oxygenated blood into lungs through pulm artery.
Levo-TGA is double discordance; acyanotic defect because morphological left and right ventricles with their corresponding atrioventricular valves are also transposed. Systemic and pulmonary circulation connected.
In dextro the aorta is anterior and to right of PA
In levo- aorta is anterior and to the left of PA
What anatomic sites may allow for mixing of blood and therefore life can be sustained in TGA?
Patent foramen ovale or atrial septal defect
Ventricular septal defect
Patent ductus arteriosus
What are the risk factors for TGA?
Maternal risk factors Age over 40 years old Maternal diabetes Rubella Poor nutrition Alcohol consumption
What are the clinical features of TGA?
Cyanosis appears in first 24 hrs if no mixing at atrial level
Mild cyanosis particularly when crying might be evident
Signs of CHF - tachypnoea, tachycardia, diaphoresis, failure to gain weight - may become evident over first 3-6 weeks as pulmonary blood flow increases
On examination: Prominent right ventricular heave Single second heart sound Systolic murmur potentially if VSD present No signs of resp distress
What are the differentials of TGA?
TOF - CXR shows boot shaped heart in TOF, ECHO shows pulmonary cyanosis, overriding aorta, RVH
Tricuspid atresia - ECG shows left axis deviation in this
What are the investigations for TGA?
Pulse oximetry shows cyanosis
Can be discrepancy between upper and lower limbs
Capillary blood gas may show metabolic acidosis with decrease pO2.
Echo definitive for diagnosis, shows abnormal position of aorta and pulmonary arteries
CXR - egg on a string
Narrowed upper mediastinum, cardiomegaly, increased pulmonary vascular markings
What is the management of TGA?
Initial:
Emergency prostaglandin e1 infusion keeping DA open
Correct metabolic acidosis
Emergency atrial balloon septostomy to allow for mixing
Long term:
Surgical correction - arterial switch operation, usually performed before age of 4 weeks
Long term follow up and counselling in future if pt wishes to get pregnancy
What are the long term consequences of TGA?
Prognosis depends on complexity and how it was repaired
Neopulmonary stenosis
Neoaoertic regurgitation
Neoaortic root dilatation
Coronary artery disease
Obstructed coronary arteries
Neurodevelopmental abnormalities
Low gestational age and high pre-operative lactate important predictors of poor developmental outcome
What is Ebstein’s anomaly?
A congenital heart condition where the tricuspid valve is set lower in the right side of the heart towards the apex
Leads to a bigger right atrium and a smaller right ventricle
Leads to poor flow from right atrium to right ventricle and poor flow to pulmonary vessels
Right to left shunt across atria via atrial septal defect
Bypasses lungs and leads to cyanosis
What condition is Ebstein’s anomaly associated with?
Wolff-Parkinson-White syndrome
What is the presentation of Ebstein’s anomaly?
Evidence of heart failure Gallop rhythm on auscultation - addition of third and fourth heart sounds Cyanosis SOB, tachypnoea Poor feeding Collapse or cardiac arrest
If associated atrial septal defect too, present few days after birth when ductus arteriosus closes because prev was allowing blood flow from aorta to pulmonary vessels to be oxygenated and minimising. cyanosis
How is Ebstein’s anomaly diagnosed?
Echocardiogram
What is the management of Ebstein’s anomaly?
Medical management to treat arrhythmias and heart failure
Prophylactic abx for infective endocarditis
Definitive management and surgery to correct defect
What is tricuspid atresia?
Absence of tricuspid valve associated with hypoplasia of right ventricle
What is the pathophysiology of tricuspid atresia?
Valve is absent, right ventricle hypoplastic due to absence of inflow into right ventricle
Often a VSD also present
Needs to be inter-atrial communication to allow systemic venous return out of heart via LA and LV.
Most cases PA arises from hypoplastic left ventricle so there is reduced pulmonary flow
30% cases great arteries transposed, systemic perfusion poor
Commonly associated with coarctation of aorta or interrupted aortic arch
What are the clinical features of tricuspid atresia?
Poor feeding if late diagnosis
On examination:
Progressive cyanosis
Could palpate a systolic thrill with pulmonary stenosis but rare, hepatomegaly if heart failure
Single S2 with pan-systolic murmur due to VSD on auscultation
Continuous mechanical murmur if PDA
What are the investigations for tricuspid atresia?
ECG with superior QRS
CXR showing reduced or increased pulmonary markings, heart size may be normal or increased
ECHO
Atretic tricuspid valve
Mandatory right to left flow across atrial septum
Small right ventricle
Enlarged right atrium, left atrium and left ventricle
What is the initial management of tricuspid atresia?
IV PGE1 infusion to prevent closure of PDA
Balloon atrial septostomy if inter-atrial communication inadequate
What is the surgical management of tricuspid atresia?
Fontan circulation is final stage and is palliative not curative.
- At birth - shunt between subclavian artery and pulmonary artery to increase forward flow into pulmonary arteries.
- At 3-6 months - BGS shunt creates an end-to-side anastomosis between the superior vena cava and pulmonary artery
- Definitive procedure at 3-4 years - Fontan procedure to divert inferior vena cava flow directly to the PA by bypassing the right atrium or creating a tunnel within it.
Extra-cardiac conduit has lower operative mortality, lower incidences of early and late arrhythmias, improved haemodynamics.
Patients are started on anti-coagulation.
What are the early complications following the Fontan procedure?
Low cardiac output and heart failure
Persistent pleural effusion and chylothorax
Thrombus formation in venous pathways
What are the late complications following the Fontan procedure?
Supraventricular arrhythmias
Protein losing enteropathy - result of persistent pleural effusion
Progressive drop in arterial saturations resulting from obstruction in venous pathways
What is the nitrogen washout test?
Used to determine presence of heart disease in a cyanosed neonate
Placed in 100% oxygen for 10 mins
If right radial arterial pO2 remains low from a blood gas - cyanotic heart disease can be made if lung disease and PPH can be excluded
If pO2 <20 kPa, not cyanotic
What are the causes of common mixing?
Blue and breathless
Complete atrioventricular septal defect
Complex congenital heart disease e.g. tricuspid atresia
What are the causes of outflow obstruction in the sick infant?
Coarctation of the aorta
Interruption of the aortic arch
Hypoplastic left heart syndrome
What is hypoplastic left heart syndrome and its management?
Underdevelopment of the entire left side of the heart Mitral valve is small or atretic Left ventricle is diminutive Aortic valve atresia Ascending aorta very small Coarctation of the aorta
Sickest of all neonates, with duct-dependent systemic circulation
No flow through the left side of the heart = ductal constriction leads to acidosis and cardiovascular collapse
Weakness or absent peripheral pulses
Norwood procedure, then shunt, then Fontan at 3 years
What is the most common childhood arrhythmia?
Supraventricular tachycardia
Presents with symptoms of cardiac failure; poor cardiac output and pulmonary oedema
Cause of hydrops fetalis and intrauterine death
What will an ECG show in SVT?
Narrow complex tachycardia
250-300 bpm
Delta wave in WPW
If severe heart failure - inverted T waves
What is the management of SVT?
Circulatory and resp support
Vagal stimulating manoeuvres
IV adenosine terminates tachycardia
Electrical cardioversion with synchronised DC shock if adenosine fails
