Congenital Heart Disease: non cyanotic Flashcards
Which are the left to right shunts?
Atrial septal defect
Ventricular septal defect
Patent ductus arteriosus
Outline ASD
There are 2 main types of ASD:
- Secundum ASD (80%)
- Defect in the centre of the atrial septum
- Involves the foramen ovale
- Partial atrioventricular septal defect (AVSD) or primum ASD
- Partial AVSD
- Defect in the atrioventricular septum
- There is an interatrial communication between the bottom end of the atrial septum and the atrioventricular valves (primum ASD)
- There are abnormal atrioventricular valves, with a left atrioventricular valve which has three leaflets and tends to leak (regurgitant valve)
Clinical features of ASD
Symptoms
- None (COMMON)
- Recurrent chest infections/ wheeze
- Subtle SOBOE or palpitations (2nd decade)
- Arrhythmias (4th decade onwards)
Signs
- Soft ejection systolic murmur
Best heard at the upper left sternal edge
(due to increased flow across the pulmonary valve because of the LEFT-to-RIGHT shunt) - Fixed and widely split 2nd heart sound- (often difficult to hear) due to right ventricular stroke volume being equal in both inspiration and expiration
- In partial AVSD- a partial pansystolic murmur may be heard from atrioventricular valve regurgitation
Investigations of ASD
Examination
Basic observations
ECG
* Can be normal
* Secundum ASD: Partial RBBB (common)
Right axis deviation (due to right ventricular enlargement)
Partial AVSD
* Superior QRS- mainly negative in AVF
* Occurs due to a defect in the middle of the heart where the AVN is found
* The displaced node then conducts to the ventricles superiorly, giving the abnormal axis
CXR: Normal, Cardiomegaly, Enlarged pulmonary arteries, Increased pulmonary vascular resistance
Echocardiography- DIAGNOSTIC
* Mainstay of diagnostic investigations
* Delineates the anatomy
Management of ASD
Secundum ASD
Endovascular/ percutaneous closure
- Cardiac catherization + insertion of occlusive device
- Echocardiography and fluorescent guidance is used
Partial ASD
- Managed by surgical correction under direct vision using cardiopulmonary bypass
- Can also be done with video-assistance
Treatment usually undertaken at 4-5 years of age in order to prevent right heart failure and arrhythmias in later life
Complications of ASD
Complications
Late- atrial arrhythmias, stroke, device thrombosis, device erosion
Prognosis
Isolated ASDs repaired in childhood have excellent prognosis with similar survival to the general population
Isolated ASDs if not diagnosed until late adulthood can cause increasing fatigue, SOB, palpitations and manifestations of heart failure
Outline VSD
MOST COMMON- responsible for 30% of cases of congenital heart disease
This is where there is a defect anywhere in the ventricular septum:
* Peri-membranous- adjacent to the tricuspid valve
* Muscular- completely surrounded by muscle
They can be categorised based on their size:
* SMALL- smaller than the aortic valve (usually ≤ 3 mm)
* LARGE- the same size or larger than the aortic valve
Associated with different conditions
Chromosomal disorders:
* Trisomy- 13, 18, 21
* 22q11 deletion (Di George)
* 45 XO (Turner’s)
* Foetal alcohol syndrome
Clinical features of VSD
Small VSD
- Asymptomatic (normal feeding and weight gain), detected incidentally
- Loud pansystolic murmur at the LOWER left sternal edge (loud murmur implies a smaller defect)
- Quiet pulmonary second sound (P2)
- Higher risk of endocarditis
Large VSD
Symptoms
* SOBOE (i.e. feeding) so less feeding, faltering weight
* Heart failure with breathlessness
* Faltering growth after 1 week old
* Recurrent chest infections
Signs
* Tachypnoea, tachycardia and enlarged liver from heart failure
* Active precordium
* Soft pansystolic murmur or NO murmur (implying large defect)
* Apical mid-diastolic murmur (from increased blood flow across mitral valve)
* Loud pulmonary second sound (P2)- from raised pulmonary artery pressure
Investigations of VSD
Small VSD
* Examination
* Basic observations
* CXR and ECG- usually NORMAL
* Echocardiography (DIAGNOSTIC)- demonstrates the precise anatomical defect, haemodynamic effects can be assessed using Doppler
Large VSD
CXR
* Cardiomegaly
* Enlarged pulmonary arteries
* Increased pulmonary vascular markings
* Pulmonary oedema
ECG
* Biventricular hypertrophy by 2 months of age
* Upright T wave if pulmonary hypertension
Echocardiography
* Demonstrates the anatomy of the defect
Management of VSD
Small VSD
* These lesions usually close SPONTANEOUSLY
* This is demonstrated by disappearance of the murmur with a normal ECG and echocardiogram
* Whilst the VSD is present, prevent bacterial endocarditis by maintaining good dental hygiene
Large VSD
Medical management
* Heart failure is treated with diuretics (often captopril)
* ACEi may be used to reduced afterload
* Additional calorie input
Surgical management
* Catheter/ percutaneous closure
* Surgery is usually performed at 3-6 months to: Prevent permanent lung damage from pulmonary hypertension and high blood flow (i.e. preventing Eisenmenger syndrome)
* Manage heart failure and faltering growth
Complications of VSD
Large VSD
Complications
* Eisenmenger’s syndrome (reversal of shunt: Right-to-Left)
* Perimembranous defects causing aortic valve prolapse and aortic regurgitation
* Bacterial endocarditis
* RBBB
Prognosis
Isolated VSD is good, can spontaneously close if small
More likely to occur in those < 1 year but less likely > 2 years
Prognosis much worse with pulmonary hypertension or Eisenmenger’s syndrome
Outline PDA
This is due to a defect in the constrictor mechanism of the duct. The flow of blood across a PDA is then from the aorta to the pulmonary artery.
Clinical features of PDA
Murmur = continuous ‘machine-like’ / Gibson’s murmur at ULSE
o Left sub-clavicular thrill
o Heaving apex beat
o Wide pulse pressure
o Large volume, bounding, collapsing pulses
o Respiratory symptoms (increased work) à apnoea, bradycardia, high O2 need
o May be difficult to wean off a ventilator
Investigations for PDA
CXR and ECG are usually NORMAL
NOTE: if the PDA is large and symptomatic, the features are indistinguishable from those with a large VSD
Echocardiography- the duct is readily identified
Management for PDA
Medical: indomethacin (NSAID) -> will promote duct closure
Premature infants (< 32 weeks)
* IV Indomethacin (inhibits prostaglandin synthesis) closes the connection
* Surgical ligation- done if indomethacin closure fails
Term infants/ children
* Small-moderate: Percutaneous Catheter Device/ Endovascular closure
* Catheter placed through vein/ artery into the heart
* Insert a coil (small PDAs) or occlusive device (larger PDAs) using X-ray guidance
* Large: Surgical ligation
* Stitch and/or clip is placed around both ends of the ductus arteriosus
Diuretics
In asymptomatic individuals- percutaneous closure is done at 1 year of age.
In symptomatic infants- it is attempted to be delayed until > 6 months
Summary
