DR SIMON ATTARD MONTALTO
Abnormal connections:
Atrial septal defect (ASD)
Ventricular septal defect (VSD)
Patent ductus arteriosus (PDA)
Abnormal valves/vessels:
Pulmonary stenosis (PS)
Aortic stenosis (AS)
Coarctation of aorta (Coarct)
Mitral stenosis
Ebstein's anomaly
Obstruction to flow:
Tricuspid atresia (TA)
Pulmonary atresia (PA)
Hypoplastic left heart
Hypoplastic right heart
Abnormal connections:
Transposition great vessels (TGA)
Total anomalous pulmonary venous drainage (TAPVD)
Complex:
Fallot's tetralogy
Arioventricular septal defect (AVSD)
Truncus arteriosus
Corrected transposition
Double outlet right ventricle
Single ventricle
Up to 1% of all new babies born may have some form of congenital heart defect (CHD). The relative incidence is shown below:
|
Type of CHD |
% of all CHD |
|
VSD |
25-30 |
|
ASD |
6-8 |
|
PDA |
6-8 |
|
Fallot's |
5-7 |
|
Coarct |
5-7 |
|
PS |
5-7 |
|
AS |
4-7 |
|
TGA |
3-5 |
|
Hypoplastic LH |
1-3 |
|
Hypoplastic RH |
1-3 |
|
Truncus arteriosus |
1-2 |
|
TAPVD |
1-2 |
|
TA |
1-2 |
|
Single ventricle |
1-2 |
|
Others |
5-10 |
Acyanotic CHD Abnormal connections
1. ASD:
Abnormal connection between atria, low in atrial septum (primum defect), or at the site of the fossa ovalis (secundum defect), resulting in an abnormal, 'excess' flow of oxygenated blood from the left to the right atrium.
Symptoms: Asymptomatic; increased chest infections.
Signs: Pink; normal pulses, BP and precordium; second heart sound (HS2) - wide (and fixed) splitting; 2-3/6 ejection systolic murmur (ESM) at upper left sternal edge (LSE).
ECG: 'P' wave slightly peaked.
CXR: Normal or slight cardiomegaly and plethora.
2. VSD
Abnormal connection between ventricles, often in upper, membranous part of septum. Blood flows under pressure from left to right ventricle.
Symptoms: Short of breath on exertion (SOBOE), eg with feeds; chest infections; failure to thrive (FTT).
Signs: Pink; normal pulses and BP; thrill LSE; right ventricular (RV) heave; HS2 (pulmonary component) loud; 2-6/6 pansystolic (PSM) lower LSE; hepatomegaly if in congective cardiac failure (CCF).
ECG: Peaked 'P' wave; R+L hypertrophy or normal.
CXR: Normal or cardiomegaly and plethora.
Persistant connection between bifurcation of pulmonary artery and aortic arch. Blood flows under pressure from the aorta into the pulmonary arteries.
Symptoms: None or CCF and chest infections.
Signs: Pink; large volume, 'collapsing' pulses; BP shows wide pulse pressure; hyperdynamic precordium; normal HSs; continuous 'machinery' murmur at upper LSE, L supraclavicular area and back. Signs CCF.
ECG: L or biventricular hypertrophy.
CXR: Moderate cardiomegaly with plethora.
4. PS:
Constricted valve ring impedes foward flow of desaturated blood into the lungs. PS is associated with a dysplastic valve in Noonan's syndrome.
Symptoms: None or exercise intolerance. Rarely RHF.
Signs: Pink; normal pulses, BP; occasional thrill upper LSE; HS2 (P component) may be loud and preceded by an ejection click (stiff valve which snaps open) or absent (immobile valve); ESM in 'P' area radiating through to the back.
ECG: RV hypertrophy.
CXR: Prominent pulmonary conus due to post stenotic dilatation; RV hypertrophy.
5. AS
Consticted valve ring (occasionally associated with bicuspid valve) or supra or sub-valvular membrane - all impede foward flow into the aorta from the LV.
Supravalvular AS is seen in William's syndrome.
Symptoms: None or exercise intolerance; syncopal attacks; arrhythmias; L ventricular failure (LVF); sudden death.
Signs: Pink; low volume pulses; thrill suprasternal notch; LV impulse. HS2 (aortic component) loud; ejection click (valvular stenosis only); ESM upper right sternal edge and neck.
ECG: LV hypertrophy.
CXR: Prominent aortic arch; slight LVH.
6. Coarct:
Narrowing (discrete 'shelf' or long segment) in aorta, usually (95%) just beyond L subclavian artery resulting in 'proximal' hypertension in upper limbs (unless constriction precedes the L subclavian - now hypertension in R upper limb alone). Typical lesion of Turner's syndrome (often with bicuspid aortic valve).
Symptoms: None or SOB, weakness after exercise. Severe cases rely on the PDA to supply the descending aorta and may present in collapsed state in neonatal period (when PDA closes).
Signs: Pulse weak in lower limbs with brachio-femoral delay; BP high in upper limbs and low in legs; normal HSs; late systolic murmur at the upper LSE radiates to the back and neck; additional continuous murmurs over back and axillae.
ECG: LVF (late sign).
CXR: Cardiomegaly, plethora in neonates. Post-stenotic dilatation of arch, LV prominance and rib notching in older children.
1. i. TGA without VSD
Aorta comes off RV; pulmonary artery from LV. This results in two separate circulations 'in parallel', and an additional R-L connection is essential to maintain life.
Symptoms: Severe cyanosis, tachypnoea.
Signs: Ill hypoxic neonate with hyperdynamic precordium, tachycardia, tachypnoea; HS2 may appear single and murmurs may be absent.
ECG: R sided dominance within normal limits.
CXR: Moderate cardiomegaly and narrow mediastinum resulting in bell-clapper or 'egg-on-side' appearance. Pulmonary plethora mild.
2. ii. TGA with VSD
The VSD now permits R to L flow at ventricular level resulting in excess flow into the lungs. Though CCF is severe, cyanosis is mild.
Symptoms: CCF.
Signs: CCF with subtle cyanosis, PSM at LSE.
ECG: prominent P wave; R or R+L ventricular hypertrophy; R axis deviation.
CXR: Cardiamegaly, narrow mediastinum, marked plethora.
3. TAPVD
Pulmonary veins do not connect with the LA and return directly to the RA or reroute via mediastinal veins (eg SVC, brachiocephalic) in supradiaphragmatic TAPVD. Pulmonary venous return is now usually unobstructed. Occasionally the veins aggregate into a confluence behind the LA and return to the RA via a long circuitous route beneath the diaphragm and often obstruct).
Symptoms: Slight breathlessness (if unobstructed); severe SOB and cyanosis if obstructed.
Signs: Mild cyanosis, severe tachypnoea, hepatomegaly.
ECG: RV hypertrophy.
CXR: Superior mediastinal shadow with cardiomegaly (in unobstructed supradiaphragmatic type) results in cottage loaf/snowman appearance; obstucted TAPVD presents with a small heart due to poor venous return with marked plethora.
1. TA
There is no foward flow through the tricuspid valve and blood shunts R-L across the foramen ovale/ASD. A VSD is often present allowing blood to flow from LV to RV and then into the lungs.
Symptoms: SOB, cyanosis.
Signs: Tachypnoea, cyanosis, PSM at LSE.
ECG: LV hypertrophy, L axis deviation/superior axis..
CXR: Moderate cardiomegaly, pulmonary oligaemia.
2. i. PA without VSD
The atretic pulmonary outflow prevents foward flow of blood into the lungs. The pulmonary flow may be sustained by a PDA. Without a VSD the RV is underdeveloped and blood flows to the L side at atrial level.
Symptoms: Collapse as PDA closes.
Signs: Cyanosis, tachypnoea, HS2 single.
ECG: RA hypertrophy (peaked P wave); LV hypertrophy;
small RV complexes.
CXR: Variable heart size; marked pulmonary oligaemia.
4. ii. PA with VSD
Blood is now able to shunt R to L at both atrial and ventricular levels. The RV is not underdeveloped. Collateral vessels directly from the aorta (at systemic pressure) supply some parts of the lungs, resulting in patchy pulmonary congestion and hypertension.
Symptoms: Cyanosis,SOB, chest infections, CCF, FTT.
Signs: Cyanosis, HS2 single, continuous murmurs over back (due to collaterals), signs CCF.
ECG: RV hypertrophy.
CXR: Variable cardiomegaly, absent pulmonary conus, variable and patchy pulmonary vascular markings.
5. Hypoplastic Left heart:
The main pumping chamber is severely underdeveloped resulting in CCF in the first few weeks of life. At present there is no meaningful palliative or corrective procedure for this lethal condition.
Symptoms: SOB, severe CCF.
Signs: Weak pulses, poor perfusion and cardiac output.
ECG: R axis deviation, RVH, small LV complexes.
CXR: Cardiomegaly with pulmonary plethora.
1. Fallot's tetralogy
This condition comprises of (i) RV outflow tract obstruction along the infundibulum. As a result (ii) the RV hypertrophies. In addition there is (iii) a large VSD beneath the aortic outlet and (iv) the aorta straddles both ventricles.
Symptoms: SOB; poor exercise tolerance; squatting to relieve tiredness; paroxysmal hypercyanotic episodes ('blue spells'), followed by syncope; FTT.
Signs: Cyanosis; RV heave at LSE; systolic thrill at upper LSE; single HS2 (P component not heard); ESM at the upper LSE (due to infundibular not valvular stenosis and therefore no opening click). The ESM disappears during severe blue spells. The large VSD causes little turbulence and therefore does not produce a murmur.
ECG: R axis deviation; RV hypertrophy.
CXR: Small pulmonary conus with RV hypertrophy results in boot shaped heart (coeur en sabot); decreased pulmonary flow; occasionally R sided aortic arch.
2. AVSD
The central portion of the heart (endocardial cushion) does not develop resulting in a hole straddling both the atria and ventricles. In addition the A-V valves are abnormal - a single large (and incompetent) A-V valve separates the atria from the ventricles (not tricusid and mitral valves). There is free communication between all 4 chambers and the predominant flow is from LV to RA, and then into the lungs. This lesion is classically seen in Down's syndrome.
Symptoms: SOB, CCF.
Signs: CCF; systolic thrill and PSM at LSE.
ECG: Superior axis.
CXR: Cardiomegaly with pulmonary plethora.