a logical apprach to the congenitcl malformed heart

Question 1

heart is derived from ?

Answer 1

mesoderm

Question 2

by 23 days post conception the L+r endocaridal tubes?

Answer 2

fuse to fomra single epithelial heart tube

Question 3

anatomy of developing heart?

Answer 3

Question 4

steops for development of atrium nd venticle?

Answer 4

cranial portion - aotic sac - aoric arches

bulbis cordis - primative ventricle + truncus arteriosus + conus cordis

caudal portion - sinus venosus + atriums

Question 5

cardiac function?

Answer 5

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

Question 6

fetal circulation?

Answer 6

Main elements
-Oxygenated blood
from placenta streams
to head
-Deoxygenated blood
from head streams to
pulmonary artery
-RV is equally
dominant with LV

Question 7

post notal circulation?

Answer 7

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 (♣)

Question 8

draw a graph of the pulmonry vacular changes durig deliverry

Answer 8

Question 9

escribe the cardiac cycle

Answer 9

Question 10

murmur?

Answer 10

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

Question 11

innocent mumur?

Answer 11

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

Question 12

types of innocent mumur?

Answer 12

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)

Question 13

where to listen on the chest for inocent systolic murmurs?

Answer 13

Question 14

where to listen for innocent diastolic murmurs?

Answer 14

Question 15

where to listen for venous hum and PDA?

Answer 15

Question 16

structural heart disease aetiology?

Answer 16

Aetiology
– Chromosomal anomaly (trisomies, microdeletions,
DNA mutations)
– Non-hereditary syndrome (CHARGE, VACTER)
– Maternal (diabetes, phenyketonuria)
– Toxin (alcohol, anticonvulsants, warfarin)
– Multifactorial
– Presence of other malformation

Question 17

how to classifcy congential heart disease?

Answer 17

1. acyanotic
   - Lto R shunt (ASD, VSD, PDA)
   - obstructive (PS, AS, coarctation)
2. cyanotic
   - ToF, TGA

Question 18

l to r shunts

Answer 18

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

Question 19

obstructive lesions?

Answer 19

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)

Question 20

r to l shunt?

Answer 20

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

Question 21

asd, vsd and PDA?

Answer 21

atrial septal defect

ventricular setpal defect

patent ductus arteriosus

Question 22

asd?

Answer 22

~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

Question 23

Ventricular sepatal defect (VSD)?

Answer 23

~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

Question 24

PDA?

Answer 24

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)

Question 25

pathophysiologt of R to L shunt?

Answer 25

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

Question 26

ToF?

Answer 26

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

Question 27

TGA?

Answer 27

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%.)

Question 28

obstructive lesions?

Answer 28

Examples – Pulmonary stenosis – Aortic stenosis – Coarctation of the aorta • Pathophysiology – Increased pressure in upstream vessel or chamber – Ventricular hypertrophy – Risk of ventricular failure

Question 29

pulmonary stenosis?

Answer 29

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

Question 30

aortic stenosis?

Answer 30

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

Question 31

CoA?

Answer 31

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