Atrial Septal Defect (ASD)

Features

•    Fixed split S2 (due to delayed RV emptying)

•    Ejection systolic murmur (increased flow across pulmonary valve)

•    Mid-diastolic murmur at tricuspid area (increased flow across tricuspid)

Types

•    Ostium secundum: most common (~75%)

•    Ostium primum: associated with AV valve anomalies (seen in Down syndrome)

•    Sinus venosus: near SVC

Complications

•    Pulmonary hypertension

•    Right heart failure

•    Atrial arrhythmias (AF)

•    Paradoxical emboli

Ventricular Septal Defect (VSD)

Features

•    Pansystolic murmur at lower left sternal edge

•    May have mid-diastolic flow murmur at apex (increased mitral flow)

•    Large defects → HF symptoms (failure to thrive in infants)

Natural history

•    Small defects may close spontaneously

•    Large uncorrected → Eisenmenger syndrome

Patent Ductus Arteriosus (PDA)

Features

•    Continuous "machinery" murmur at left infraclavicular area

•    Bounding pulse, wide pulse pressure

Risk factors

•    Prematurity

•    Maternal rubella infection

Complications

•    Eisenmenger syndrome (late reversal to R → L shunt, cyanosis)

•    Heart failure

•    Endarteritis

Management

•    Indomethacin (NSAID) in preterm infants

•    Surgical or catheter closure

Coarctation of the Aorta

Features

•    Radiofemoral delay

•    Higher BP in upper limbs vs lower limbs

•    Weak/absent femoral pulses

•    Scapular systolic murmur

•    Rib notching on CXR (collateral vessels)

Associations

•    Bicuspid aortic valve (up to 50%)

•    Turner syndrome

Complications

•    Hypertensive crisis

•    Aortic dissection

•    Cerebral haemorrhage (berry aneurysms)

Tetralogy of Fallot

Features

•    Cyanosis (esp. during "tet spells" in infants)

•    Squatting improves symptoms (↑ SVR → ↓ R→L shunt)

•    Boot-shaped heart on CXR (RV hypertrophy)

Components

•    VSD

•    RV outflow tract obstruction (pulmonary stenosis)

•    Overriding aorta

•    RV hypertrophy

Eisenmenger Syndrome

Mechanism

•    Chronic L→R shunt (ASD, VSD, PDA) → pulmonary hypertension → reversal to R→L → cyanosis

Features

•    Central cyanosis

•    Clubbing

•    Polycythaemia

•    Reduced exercise tolerance

Extra Revision Pearls

•    ASD clue → fixed split S2; think paradoxical emboli risk

•    VSD clue → lower left sternal edge murmur; large VSD → heart failure signs

•    PDA clue → continuous murmur, wide PP, bounding pulse

•    Coarctation clue → young HTN, rib notching, radiofemoral delay

•    Tetralogy clue → cyanosis, squatting improves; boot-shaped heart

•    Eisenmenger clue → any long-standing L→R lesion, cyanosis later