Any agent or substance which can cause malformation of an embryo or birth defects.
Critical period of heart development
From about day 20 to 50.
However, deviation from normal pattern of development at any one time may produce one or more cardiovascular defects.
Clinical features of congenital heart defects
- Vary from asymptomatic through full spectrum to incompatible with life.
- Susceptible to infective endocarditis.
- Failure to attain normal growth or development
Clinical signs (Vary with anatomical lesions)
- Murmurs, thrills
- Radio-femoral delay
Classification of congenital heart disease
Embryological origin of classification
- Abnormalities of position
- Abnormalities of interatrial septum
- Abnormalities of interventricular septum
- Abnormalities in the division of the truncus arteriosus
- Abnormal transformation of aortic arches
- Persistence of fetal circulation
Abnormalities of position
- Dextrocardia (isolated)
- Dextrocardia (situs inversus)
Isolated dextrocardia symptoms
Often associated with other (severe) cardiac anomalies (e.g. transposition of great vessels, single ventricle).
Situs inversus symptoms
Abnormalities of interatrial septum
Atrial septal defect
- Secundum type (most common)
- Primum type
- Patent foramen ovale
Clinical presentation of ASD
Female: Male = 2:1
- Often asymptomatic for many years
- Dyspnoea, chest infections, cardiac failure, arrhythmias (especially AF)
- Eisenmenger's syndrome (rarely)
- Fixed splitting of S2
- Systolic flow murmur over pulmonary valve (often no murmur)
- Secundum type - often associated valve abnormalities/murmurs
- Surgical repair
- Cardiac catheterisation - implantable closure device
Abnormalities of interventircular septum
- VSD most common CHD
- Membranous VSD
- Muscular VSD
Clinical presentation of VSD
- May be asymptomatic if small
- Tachypnoea, indrawing of lower ribs on spiration
- Cardiac failure (4-6 weeks)
- Eisenmenger's syndrome
- Harsh pansystolic murmur, maximal at LSE
- Murmur often louder when defect is small
- Third or fourth heart sound
- Often palpable systolic thrill
- Cardiac failure treated medically with digoxin and diuretics
- Persistent failure is indicated for surgical closure (percutaneous closure devices).
Abnormalities in the division of the truncus arteriosus
- Persistent truncus arteriosus
- Complete transposition of the great vessels
- Pulmonary valve anomalies
- Tetralogy of the fallot
Tetralogy of the fallot
- Pulmonary stenosis (outflow obstruction)
- R ventricular hypertrophy
- Over-riding aorta
Abnormalities in the division of the truncus arteriosus clinical features and management
- All severe
- Cyanosis characteristically develops shortly after birth
- Early surgical intervention
Abnormal transformation of aortic arches
- Coarctation of the aorta
- Double aortic arch
Coartctation of the aorta clinical features and management
Male: female = 2:1
Symptoms: depends on site of coarctation
- Radio-femoral delay (radio-radial delay)
- Weak femoral pulse
- Midsystolic murmur over praecordium and back
- Upper limb HTN
- Upper body may be better developed than lower body
- Surgical correction
- Balloon dilation
Main problem with double aortic arch
Main syptoms: problem with swallowing or regurgitation
Persistence of fetal circulation
- PFO (see ASD)
PDA clinical presentation
- Often asymptomatic in infancy
- Progressive symptoms of cardiac failure
- Collapsing pulse
- Continuous loud 'machinery' murmur maximal at first left intercostal space
- Progressive signs of cardiac failure
- Eissenmenger's Syndrome - late
- Cardiac catheterisation - implantable occlusive device
- Coarctationo of the aorta
- Tetralogy of Fallot
- Transposition of Great Vessels
- Persistent Truncus Arteriosis
Pulmonary HTN and reversal of left to right shunt to right to left shunt.
Chronic left-to-right shunting through congenital heart defect (e.g. VSD, PDA). Produces severe pulmonary HTN.
Because deoxygenated blood mied in systemic circulation --> cyanosis.
Clinical features of Eisenmenger's syndrome
- Loud P2
- Polycythaemia --> stroke
- Heart - lung transplant usually required
Causes of congenital heart defects
Genetic/chromosomal syndromes (20%)
- Down syndrome
- Turner syndrome
- Trisomy 13 (Patau syndrome)
- Marfan syndrome
- Retinoic acid
- Alcohol (foetal alcohol syndrome)
Other (the vast majority)
What type of CHD does down syndrome cause?
Endocardial cushion defects (ASD, VSD, atrioventricular canal defects).
What type of CHD does Turner syndrome cause?
Coarctation of the aorta
Bicuspid aortic valve
What type of CHD does trisomy 13 cause?
Patent ductus arteriosis - PDA.
What type of CHD does Marfan's cause?
Aortic and mitral valve abnoramalities.
CHD in retinoic acid
Septal defects most common.
CHD and alcohol
CHD in rubella