Common congenital heart defects

1) VENTRICULAR SEPTAL DEFECT • Incidence: 30% of all congenital defects *Anatomy* • Opening in the ventricular septum *Clinical Features* • left to right shunt • increased pulmonary blood flow —> increased pulmonary vascular resistance • excessive raised PVR —> reverses shunt [right to left] • right ventricular hypertrophy • deficient systemic blood flow
2) ATRIAL SEPTAL DEFECT • 10% of all congenital heart disease *Anatomy* • Opening in the atrial septum • 3 types: i) Ostium primum -15% of total - due to failure of septum primum to fuse with endocardial cushion - occurs low in septum - may be associated weith anomaly in medial leaflet of mitral valve ii) Ostium secundum - 70% of total - located centrally in septum near foramen ovale - normal resorptive process which leads to formation of ostium secundum is exaggerated; most of the septum primum dissappers iii) Sinus Venosus - 15% of total - located high in septum near opening of SVC - may be associated with anomalous drainage of right pulmonary vein *Clinical Features* • blood in left atrium flows into right atrium • increased volume in pulmonary vasculature —> pulmonary hypertension • 2° pulmonary hypertension: i) enlargement left atrium & ventricle ii) dyspnoea iii) reduced volume in systemic circulation —> reduced physical & mental development • shunt may reverse [become right to left]
3) PATENT DUCTUS ARTERIOSUS • Incidence: 10%; one of the most common and benign types of congenital heart disease *Anatomy* • ductus arteriosus connects the origin of the left pulmonary artery to the aorta • normally closes hours after birth - unknown why does not close in some infants *Clinical Features* • dependent on size of duct • symptoms of a left-to-right shunt: - dyspnea - fatigue - diminished growth - cardiac failure • as may develop progressive increase in pulmonary hypertension —> right-to-left shunt, early repair is recommended
4) PULMONIC STENOSIS • Incidence: 7% of all congenital defects *Anatomy* • 4 types: 1) valvular stenosis [80%] 2) infundibular stenosis 3) pulmonary artery stenosis 4) peripheral pulmonary stenosis *Clinical Features* • causes obstruction to ejection of blood from right ventricle —> increased RV workload —> RV hypertrophy —> RV failure —> increased CVP • if severe stenosis —> cyanosis 2° right-to-left shunt
5) COARCTATION OF THE AORTA • 7% of all congenital defects *Anatomy* • congenital narrowing of the descending aorta usually in the vicinity of the ductus arteriosus • aortic-valve anomalies occur in 80% • coarctation is usually mild but may be quite tight or atretic • distal aorta receives blood supply via collaterals (branches of subclavian, intercostal, vertebral & anterior spinal) • 2 types: i) Preductal - patent ductus arteriosus - often associated with other intracardiac abnormalities - most commonly seen in infants ii) Postductal -may be only associated with aortic-valve abnormalities - seen in older children & adults *Clinical Features* • symptoms usually absent in childhood — growth & development is normal • adult patients are usually asymtomatic • absent or diminished femoral pulses • hypertension —> left ventricular failure [generally only seen in infants] • headaches • leg fatigue; intermittent claudication
6) AORTIC STENOSIS • Incidence: common congenital defect; 6% *Anatomy* • an bicuspid aortic valve usually becomes stenotic in adulthood • stenotic aortic valves are also usually bicuspid *Clinical Features* • varies with degree of stenosis • causes obstruction to ejection of blood from left ventricle —> increased LV workload —> LV hypertrophy —> LV failure —> increased PAW —> pulmonary congestion & oedema • coronary & cerebral circulation insufficiency are common —> dizziness, syncope, angina pectorus, fatigue • 30% incidence of sudden death! [therefore limit physical activity]
7) TETRALOGY OF FALLOT • Incidence: 6% of all forms of congenital heart disease • most common cardiac malformation responsible for cyanosis after 1 year age *Anatomy* • Four components: 1) VSD 2) obstruction to right ventricular outflow 3) overriding of the aorta 4) right ventricular hypertrophy • pulmonary stenosis is usually valvular & infundibular *Clinical Features* • Clinical picture is dependent on degree of right ventricular outflow obstruction: - with mild stenosis the shunt is left-to-right ‘pink tetralogy’ - with severe stenosis the shunt is right-to left • most children are not clinically cyanotic in first years of life but as the stenosis becomes more severe, see development of a right-to-left shunt thereby allowing more of venous return to bypass lungs and directly enter aorta —> cyanosis • at first cyanosis is only evident on exertion —> cyanosis at rest • clubbing of digits
8) TRANSPOSITION OF GREAT VESSELS • 4% of all congenital defects *Anatomy* • aorta arises from right ventricle and is located anterior to the pulmonary artery • pulmonary artery arises from left ventricle *Clinical Features* • blood in left atrium flows into right atrium • increased volume in pulmonary vasculature —> pulmonary hypertension • 2° pulmonary hypertension: i) enlargement left atrium & ventricle ii) dyspnoea iii) reduced volume in systemic circulation —> reduced physical & mental development • shunt may reverse [become right to left]