a logical apprach to the congenitcl malformed heart Flashcards
heart is derived from ?
mesoderm
by 23 days post conception the L+r endocaridal tubes?
fuse to fomra single epithelial heart tube
anatomy of developing heart?
steops for development of atrium nd venticle?
cranial portion - aotic sac - aoric arches
bulbis cordis - primative ventricle + truncus arteriosus + conus cordis
caudal portion - sinus venosus + atriums
cardiac function?
Heart muscle begins to contract
between Days 17 – 21 of embryonic life
• The increase in cardiac output parallels
growth of the embryo
• The fetal circulation differs from the
post-natal circulation
fetal circulation?
Main elements
-Oxygenated blood
from placenta streams
to head
-Deoxygenated blood
from head streams to
pulmonary artery
-RV is equally
dominant with LV
post notal circulation?
Interruption of umbilical
cord
– Loss of placental bed with
↑ SVR
– Closure of ductus venosus
Lung expansion
– ↓ PVR with ↑ PBF and ↓
PA pressure
– ↑ LA pressure with closure
of foramen ovale (♠)
– Closure of PDA due to ↑
O2
tension (♣)
draw a graph of the pulmonry vacular changes durig deliverry
escribe the cardiac cycle
murmur?
A “whooshing” noise heard on auscultation
• Produced by turbulent blood flow
• May signify
– Normal flow (“innocent murmur”)
– Increased flow volume through a normal valve
(e.g. pulmonary flow murmur in ASD)
– Valvular lesion (stenosis or regurgitation)
– Flow through an abnormal “shunt”, e.g. VSD, PDA,
arteriovenous malformation
innocent mumur?
Alternative terms
– Benign murmur
– Functional murmur
• Produced by normal or enhanced flow
through the heart
– Childhood (>50% of children)
– Fever
– Pregnancy
– Anaemia
Characteristics
– Absence of CVS symptoms
– Normal heart sounds
– Usually grade 1-3 (no thrill) – may be musical
– Systolic or continuous - never purely diastolic
– Positional variation
• Still’s murmur - louder when supine
• Venous hum – louder when upright
types of innocent mumur?
Types
– Venous hum (continuous murmur beneath
clavicles)
– Still’s murmur (musical murmur at LSE)
– Pulmonary ejection murmur
– Aortic ejection murmur
– Murmur of physiological branch pulmonary
artery stenosis (young infants)
where to listen on the chest for inocent systolic murmurs?
where to listen for innocent diastolic murmurs?
where to listen for venous hum and PDA?
structural heart disease aetiology?
Aetiology
– Chromosomal anomaly (trisomies, microdeletions,
DNA mutations)
– Non-hereditary syndrome (CHARGE, VACTER)
– Maternal (diabetes, phenyketonuria)
– Toxin (alcohol, anticonvulsants, warfarin)
– Multifactorial
– Presence of other malformation
how to classifcy congential heart disease?
- acyanotic
- Lto R shunt (ASD, VSD, PDA)
- obstructive (PS, AS, coarctation) - cyanotic
- ToF, TGA
l to r shunts
Examples: ASD, VSD, PDA
• Characteristics
– passage of oxygenated blood back to pulmonary
circulation at atrial, ventricular or great artery level
– results in
• Increased pulmonary blood flow
• Tendency to develop heart failure and PHT
• Risk of Eisenmenger syndrome, where the PVR
increases above SVR and “shunt reversal” occurs
obstructive lesions?
Examples
– Pulmonary stenosis
– Aortic stenosis
– Coarctation of the aorta
• Pathophysiology
– Increased pressure in upstream vessel or
chamber
– Ventricular hypertrophy
– Risk of ventricular failure (late feature)
r to l shunt?
Deoxygenated systemic venous blood passes from R
to L heart
– Atrial level
– Ventricular level
– Great artery level
• Results in
– Cyanosis
– Polycythaemia
• Examples
– Tetralogy of Fallot
– Transposition of the great arteries
– Unrepaired shunt lesion with Eisenmenger syndrome
asd, vsd and PDA?
atrial septal defect
ventricular setpal defect
patent ductus arteriosus
asd?
~10% of CHD
• Presentation:
– Asymptomatic murmur
– Symptoms of cardiac
failure (rarely)
• Natural history
– May close in infancy
– Cardiac failure in middle
life
– Heart rhythm disturbance
in later life
examination:
Active precordium (cardiadc beat easily felt)
• Split second heart
sound (delayed
closure of P2)
• Murmur ULSE
CXR findings:
Normal or ↑
CTR
• Prominent main
PA
• Plethoric lung
fields
echo findings:
enlarged RA
managemnet:
Medical
– Diuretics if
symptomatic
• Catheter
– Device closure
• Surgery
– Closure with
pericardium or
prosthetic material
Ventricular sepatal defect (VSD)?
~30% of CHD
Presentation:
Asymptomatic murmur
Symptoms of cardiac failure
Natural history
Smaller defects may close in
childhood
Larger defects may cause
heart failure and pulmonary
hypertension
examination:
Tachypnoea
• Hyperdynamic
precordium
• Pansystolic murmur
• May be signs of
heart failure
management:
Medical
– Calorie supplements
– Diuretics
– ?ACE inhibitor
• Surgery
– Prosthetic patch using heart-lung bypass pump
– Some VSDs are suitable for transcatheter device
closure
PDA?
7% of CHD
• Associations
– Prematurity
– Congenital rubella
syndrome
– Other congenital
lesions
– Usually isolated
• Presentation
– Small: asymptomatic
– Large: heart failure
examination:
Bounding/collapsing
pulses
• Hyperdynamic
precordium
• Continuous murmur
under left clavicle & in
back
normally found by ehco - Ductal flow is easily
visualised using
colour and
continuous-wave
Doppler
management:
Premature neonates
– Diuretics
– Fluid restriction
– Indomethacin
• Infants and children
– Medical (diuretics)
– Catheter (device
occlusion)
– Surgical (ligation)
pathophysiologt of R to L shunt?
Passage of deoxygenated systemic
venous blood from R heart to L heart
– Atrial level
– Ventricular level
– Great artery level
• Results in cyanosis, but not usually
respiratory distress
ToF?
7% of CHD
• Features
– Pulmonary stenosis
– VSD
– Aorta overrides
ventricular septum
– RV hypertrophy
• Presentation
– Cyanosis
– Murmur
examinatioin:
Cyanosis
• Normal respiratory
rate
• Heaving right
ventricle
• Soft pulmonary
heart sound
• Murmur mid to
upper left sternal
edge
CXR:
Upturned apex
(hypertrophied right
ventricle)
• Small central
pulmonary artery
• Dark lung fields due
to reduced blood
flow (“pulmonary
oligaemia”)
echi:
septum deviation, overriding aorta (AO)
on a parasternal long axis view you can see the septum, LV small and AO
natural historyu:
Progressive cyanosis
• Hypercyanotic spells
• Risk of cerebral thrombosis, abscess
• Premature death
management:
Medical / Catheter
– No definitive
treatment available
• Surgery
– Reparative surgery
• 6-18 months
• Close VSD
• Open up pulmonary
valve and artery
TGA?
transposition of the great arterires
Aorta arises from
RV
• PA arises from LV
• Parallel circulations
• Incompatible with
life unless mixing
between two
circulations
examination:
Tachypnoea
• Cyanosis
• Collapse
• Prominent right
ventricular
impulse
• May not have a murmur
management:
Resuscitate
– Prostaglandin E
infusion to keep the
duct open
– Enlarge atrial defect
(septostomy)
• Surgery
– Arterial switch
operation (The great arteries are transected & reanastomosed in the anatomically correct position.
The coronary arteries are moved separately to the
new aorta. Surgical mortality <3%.)
obstructive lesions?
Examples
– Pulmonary stenosis
– Aortic stenosis
– Coarctation of the aorta
• Pathophysiology
– Increased pressure in upstream vessel or
chamber
– Ventricular hypertrophy
– Risk of ventricular failure
pulmonary stenosis?
10% of CHD
• Features
– Asymptomatic
– Exercise
intolerance
– Arrhythmias
examination:
• Acyanotic
• Prominent RV
impulse
• Thrill
• Ejection click
• Murmur at ULSE,
referred to lung
fields
management:
Catheter
– Balloon catheter
passed across
narrowed valve
– Inflated
– Relieves narrowing in
most cases
• Surgery
– Reserved for cases
where transcatheter
intervention has failed
Balloon inflated across valve
aortic stenosis?
5% of CHD
• Presentation:
– Neonatal collapse
– Asymptomatic
murmur
– Dyspnoea, chest
pain, syncope
examination:
Weak or slow-rising
pulses
• Narrow pulse pressure
• Thrill
– suprasternal
– carotid
• Ejection click
• Murmur
– Mid-left to URSE
– Referred to carotids
management:
Exercise limitation (risk of sudden death)
• Intervene if
– Significant gradient across valve (>64
mmHg)
– Symptoms
• Type of intervention
– Valvotomy (surgical or transcatheter)
-valve replamcnert
Surgical valvotomy
if possible during
childhood (< 2%
mortality)
Balloon valvotomy is an
alternative
Patient likely to require
valve replacement
when older
CoA?
6% of CHD
Presents either as
neonatal collapse or
as an infant with
absent femoral pulses
and upper limb
hypertension.
examination:
Absent or reduced
lower limb pulses
• Radio-femoral delay
• Upper limb
hypertension
• Murmur between
scapulae (continuous
in infant type, ejection
in neonatal)
detect with echo
Natural history
– Neonatal presentation –
acute collapse, death
– Infant type - CCF
– Older child - hypertension;
risk of CVA
• Management
– Resuscitate (PGE)
– Surgical repair
– Balloon angioplasty in
older children
Adult
– Patch aortoplasty
– Balloon + stent
