Congenital Heart Diseases

 

• Background

  Epidemiology

  • Affects around 1/250 UK babies. The vast majority survive until adulthood, and 10% are not even diagnosed until then.
  • Many conditions have a variable presentation, with some apparent at birth or early infancy (poor feeding, lethargy, SOB, heart failure) and others only becoming symptomatic (if at all) later in life.
  • This page describes the commoner conditions, including the three commonest: VSD, ASD, and bicuspid aortic valve.

  Structures affected

  • Valves: bicuspid aortic valve, aortic stenosis, pulmonary stenosis, tricuspid atresia.
  • Septa: atrial or ventricular.
  • Vessels: coarctation of the aorta, transposition of the great arteries, patent ductus arteriosus, persistent truncus arteriosus.
  • Ventricles: hypoplastic left heart.

• Atrial septal defect (ASD)

  Pathophysiology

  • Ostium secundum ('second hole') defects high in septum are the commonest clinically-significant ASD. Usually first present in adulthood, though more significant defects can be detected as early as in utero.
  • Ostium primum defects present in childhood and are at the level of the mitral/tricuspid valve (the 'endocardial cushion'), where atrial and ventricular septa meet; hence they are classed as an 'AV septal defect'.
  • PFO is technically a defect of the atrial septum, though is usually considered separately from other ASDs.
  • ASD initially causes left→right shunt due to higher pressure in left. As left ventricle compliance decreases with age (possibly exacerbated by HTN), shunt is exacerbated → ever greater volume overload of right heart → pulmonary HTN → RVH → overpowers left pressure leading to Eisenmenger's phenomenon i.e. reversal of shunt (now right→left) and hence cyanosis. Occurs in 10% if untreated.

  Signs and symptoms

  • Respiratory: SOB, cyanosis, haemoptysis.
  • Chest pain
  • On auscultation: ejection systolic murmur in pulmonary area, split S1, wide fixed split S2.
  • Pulmonary HTN, which may lead to pulmonary or tricuspid regurgitation.
  • ↑JVP
  • AF

  Investigations

  • Echo is diagnostic.
  • ECG: right axis deviation, RBBB.
  • CXR: cardiomegaly from right atrial and ventricular enlargement, prominent pulmonary artery.
  • Cardiac catheterization if pulmonary HTN suspected.

  Management

  Surgical closure, either open or transcatheter.

• Ventricular septal defect (VSD)

  Pathophysiology

  • Standalone or part of conditions such as Fallot's tetralogy or trisomies 13, 18, and 21.
  • Can also be acquired post-MI (ventricular septal rupture).
  • Causes left to right shunt → blood recycles through pulmonary circulation back to left heart → left overload and LVH → pulmonary HTN.
  • Small defects are asymptomatic and can close spontaneously, while moderate and large defects may present very early and require treatment.

  Signs and symptoms

  • Harsh pansystolic murmur at left sternal edge, even with small defects.
  • Features of CHF: ↑HR, SOB, hepatomegaly.
  • Systolic thrill.
  • Parasternal heave.

  Investigations

  • Echo is diagnostic.
  • ECG: LVH signs if moderate, possibly RVH too if large defect.
  • CXR: cardiomegaly, large pulmonary arteries if large defect.

  Management

  • Initially medical as many close spontaneously. Diuretics for HF and ACEi to reduce afterload.
  • Surgical closure if unsuccessful or symptoms/complications.

  Complications

  • Aortic regurgitation.
  • Infective endocarditis.
  • Eisenmenger's (shunt reversal and cyanosis).

• Bicuspid aortic valve

  • Commonest congenital heart disease presenting in adults, male:female 2:1.
  • Usually undetected at birth and remains asymptomatic (and undetected) in 70%.
  • Can cause atrial stenosis or regurgitation.

• Coarctation of the aorta

  Pathophysiology

  • Narrowing of descending thoracic aorta, usually distal to origin of left subclavian artery, leading to LV pressure overload, CHF, HTN, and hypoperfusion of lower body.
  • Can be an isolated defect, or accompanied by bicuspid aortic valve, VSD, or Turner's syndrome.

  Signs and symptoms

  If severe, can present with early CHF, otherwise may be detected incidentally at a later stage due to various signs, including:

  • ↑BP.
  • Radio-femoral delay and/or weak femoral pulse.
  • Systolic murmur in left infraclavicular area and below left scapula.

  Investigations

  • ECG: may show LVH or RVH.
  • CXR: CHF, rib notching.
  • Echo is usually diagnostic. Should include high parasternal or suprasternal view to visualise the narrowing.
  • CT or MRI angiogram, especially if echo unclear.

  Management

  Surgery:

  • Indications: CHF or severe HTN.
  • Open angioplasty or balloon angioplasty with stenting.

  Complications

  Infective endocarditis.

• Patent ductus arteriosus (PDA)

  Pathophysiology

  • Persistence of fetal connection between pulmonary artery and aorta.
  • Moderate and large PDA can lead to symptomatic left to right shunt.
  • Increased risk in premature or low birth weight babies.

  Signs and symptoms

  Mostly asymptomatic, otherwise SOB and poor feeding in infancy. Signs:

  • Continuous machine murmur, which may be worse with smaller hole due to more turbulent flow. Sometimes just systolic, especially early in life.
  • Left subclavicular systolic thrill.
  • Displaced, heaving apex.
  • Collapsing pulse and wide pulse pressure

  Investigations

  • Echo is diagnostic.
  • CXR: large pulmonary arteries and large left heart.

  Management

  • Preterm: treat if symptomatic, IV NSAIDs (1st line) or surgical ligation (2nd line).
  • Term: wait until large/old enough for endovascular closure if asymptomatic (i.e. no heart failure), otherwise digoxin plus furosemide (1st line) or surgical ligation (2nd line) if symptomatic.

  Complications

  • CHF
  • Eisenmenger's syndrome.

• Patent foramen ovale (PFO)

  • Persistence of the foramen ovale – the opening between both atria – beyond 1 yr.
  • Prevalence is 1/5, but is usually asymptomatic and does not lead to shunt like other ASDs.
  • In adulthood it increases the risk of stroke and migraine.

• Fallot's tetralogy

  Pathophysiology

  • Commonest cyanotic congenital heart disease. Cyanosis due to ↓blood flow to lungs and right→left shunt.
  • Symptoms present at birth or develop <1 yr.
  • Can be part of DiGeorge syndrome.

  Components, ROVeR:

  • Right ventricular outflow tract obstruction (RVOT): pulmonary stenosis at valve or just below.
  • Overriding aorta: sits above VSD and connects to both ventricles.
  • VSD
  • RVH

  Signs and symptoms

  • Poor growth.
  • SOB including acute hypoxic episodes (agitated, restless, cyanosis).
  • Cyanosis and clubbing.
  • Ejection systolic murmur.
  • Toddlers may squat to increase peripheral resistance and hence reduce right→left shunt.

  DDx: Cyanotic congenital heart defects

  • Transposition of the great vessels.
  • Tricuspid atresia.
  • Total anomalous pulmonary venous return.
  • Persistent truncus arteriosus.
  • Hypoplastic left heart.
  • Eisenmenger's syndrome.

  Investigations

  • Echo is diagnostic.
  • ECG: right axis deviation and RVH, RBBB (especially after surgery).
  • CXR: normal or boot-shaped heart.

  Management

  • Surgery usually performed by 1 yr (earlier if severe), and aims to close the VSD and relieves the RVOT.
  • Until then, medical therapy if symptomatic: O2, morphine, β-blockers, and prostaglandins to keep ductus open.