Cardiology

Congenital heart disease

Ventricular septal defects

About

  • Commonest Congenital heart defect
  • A shunt exists between LV and RV
  • High risk of endocarditis

Aetiology

  • Size of defect and pulmonary pressures determine clinical picture
  • Blood flow across lesion can cause a pansystolic murmur

Structure

  • Membranous (peri membranous),
  • Trabecular muscular - often close,
  • Outlet (supracristal or subpulmonary)
  • Inlet defects. Also Small vs Large

Clinical Findings

  • VSD may produce a loud, harsh pansystolic murmur at the lower left sternal border.
  • Poor weight gain, fatigue after feeding.
  • Small VSD's "Maladie de roger can produce a loud murmur.
  • Large VSD can have minimal murmur.
  • Complications: Endocarditis, Heart failure, Arrhythmias

Investigations

  • Chest x-ray - normal with small VSD but cardiomegaly and enlarged Pulmonary arteries and increased vascular markings and possibly oedema.
  • ECG - normal if small otherwise RVH and LVH.
  • Echocardiography can anatomically place VSD and estimate pulmonary artery pressures.

Management

  • Surgical closure indicated only if persisting failure.
  • Cardiac failure in infancy usually at 6+ weeks is managed with diuretics and digoxin and ACE inhibitors. Defects may close spontaneously during infancy . The remainder may require surgical repair at 3-6 months.
  • Surgery is reserved to those who have a significant shunt before Eisenmenger's develops. Endocarditis prophylaxis is recommended.
  • Percutaneous closure with umbrella devices is still experimental

Atrial septal defects

About

  • Shunting of blood from left atrium to right atrium
  • 10% of congenital heart disease (VSD commonest)
  • Commoner in Females and Downs' syndrome

Aetiology

  • LA to RA shunt leads to an increase in pulmonary blood flow with ASD
  • Pulmonary flow > systemic flow
  • Murmurs due to increased flow across tricuspid and pulmonary valves

Types

  • Ostium primum defects - more serious and can involve mitral and tricuspid valves causing what is called a partial atrioventricular septal defect (pAVSD).
  • Ostium secundum defects - milder and more common seen in 80% involving the foramen ovale
  • Sinus venosus defect - involves upper atrial septum

Clinical Findings

  • Often no symptoms and may not be picked up until late adulthood
  • Chest infections and wheeze
  • Heart failure
  • Arrhythmias e.g. AF, Fixed split A2, ESM at upper LSE due to increase flow across pulmonary valve
  • PSM with MR due to an Ostium Primum defect with pAVSD
  • Flow across the defect is very low pressure and no murmur heard

Complications

  • Pulmonary hypertension
  • Cardiac arrhythmias e.g. Atrial fibrillation with risk of thromboembolism
  • Low risk for endocarditis and so Antibiotic endocarditis prophylaxis is not needed
  • Right heart failure
  • Stroke and paradoxical embolism

Investigations

  • CXR one can seen pulmonary plethora with enlarged RA and RV and pulmonary artery.
  • ECG ostium secundum - RBBB + RAD.
  • ECG ostium primum (pAVSD) RBBB + LAD + 1st degree AV block
  • Echocardiography defines the anatomy.
  • Right heart catheterisation to measure shunt and pulmonary artery pressure. An increased pulmonary to systemic flow
  • Role for cardiac MRI in defining anatomy

Management

  • Small uncomplicated ASDs may be monitored. Moderate to large ASDs can affect life expectancy.
  • Those with a flow ratio of 3 (Pulm flow):2(systemic flow) or greater should be closed surgically.
  • In the absence of complications operative mortality < 1%.
  • Prognosis excellent unless pulmonary hypertension (Eisenmenger's syndrome) has developed.
  • Ostium secundum can be closed with a simple occlusion device inserted by PCI.
  • Ostium Primum with pAVSD may need open heart corrective surgery.

Fallot's tetralogy

About

  • Commonest cause of Congenital cyanotic heart disease

The tetralogy of anatomical findings

  • VSD - usually large
  • Right ventricular outflow obstruction (Pulmonary stenosis - at and below the valve)
  • Overriding Aorta with respect to ventricular septum
  • Right ventricular hypertrophy secondary to the RV outflow obstruction

Aetiology

  • The main problem is that the right sided outflow obstruction leads to poor pulmonary blood flow and impaired blood oxygenation.
  • Everything depends upon RV outflow.
  • The large VSD just shunts even more blood into the right ventricle until eventually as RV pressures rise the RV pressure exceeds LV and deoxygenated blood passes into the systemic system and the patient now has Eisenmenger's syndrome and is centrally cyanosed.
  • This takes time to happen and baby may not be cyanosed at birth.
  • In some patients the RV outflow gradually gets worse up to 6-9 months of age.

Clinical Findings

  • Cyanosis - may not be apparent at birth
  • Murmur - harsh ejection systolic murmur left sternal edge. Absent P2.
  • Babies have "tet spells" possibly due to increases in the RVOT gradient and increased R to L shunting where they become hypercyanosed which can lead to MI or stroke
  • Finger and toe clubbing

Investigations

  • CXR shows a "boot shaped heart due to RVH.
  • Oligaemia - Decreased pulmonary markings due to reduced blood flow.
  • ECG - RVH. Echocardiography

Management

  • Medical management up to 6 months,
  • Definitive surgery to close VSD and reduce RVOT obstruction with a patch at 6 months.
  • Cyanosed neonate may need Blalock-Taussig shunt from subclavian artery to pulmonary artery until definitive surgery.
  • Alternatively balloon dilatation of RVOT is possible
  • Prolonged 'Tet' spells - morphine reduces pain, IV propranolol, Sedation, Hydration, Bicarbonate for acidosis, ventilation and muscle paralysis to reduce oxygen demand

Coarctation of the Aorta (CoA)

About

  • Congenital stenosis of the Aorta distal to the origin of the left subclavian artery.

Aetiology

  • Commoner in males, Turner's syndrome, Bicuspid aortic valve.
  • There is a 50 % incidence of bicuspid aortic valves in patients with CoA.
  • Berry aneurysms are seen in about 5% of those with CoA.

Clinical Findings

  • Headaches, nosebleeds or hypertension. The murmur is either continuous or systolic and reflects aortic blood flow.
  • The aortic valve may be abnormal with an associated systolic flow or stenotic murmur
  • May be an early diastolic murmur due to Aortic regurgitation.
  • Subarachnoid haemorrhage due to cerebral aneurysms.
  • A lesion distal to the left subclavian will not lead to a difference in pulses between arms but will result in a pulse delay and reduced pulse between radial and femoral vessels.

Investigations

  • MRA is the examination of choice in the older child and adult.
  • CXR- The reversed "3 appearance is due to the pre and post stenotic dilatation.
  • CXR - ^ shaped Rib notching is also seen usually laterally on the inferior surface (where the intercostal vessels are).
  • Catheterisation and pressure studies = Significant coarctation requires a gradient greater than 20 mmHg across the coarctation site

Management

  • Prostaglandin PGE1 infusion to try and keep the Ductus arteriosus open followed by surgery.
  • Hypertension may persist following correction operatively due to resetting of carotid baroreceptors which may be transient post operatively replaced by activation of the RAA system

Transposition of the great arteries

About

  • Causes cyanotic congenital heart disease

Aetiology

  • RV attaches to aorta,
  • Pulmonary artery attaches to LV.
  • Death unless mixing at some level - ASD, VSD, PDA

Clinical Findings

  • Severe cyanosis. Presents on day 1-2 when the duct closes.
  • This reduction in mixing causes marked cyanosis.
  • Cyanosis less marked if mixing at other levels e.g. VSD.
  • Clubbing eventually. No specific murmur

Investigations

  • CXR - "egg on side" heart and increased pulmonary markings.
  • Echocardiography - confirms defect

Management

  • Use IV PGE to maintain Ductus.
  • Balloon atrial septostomy - creates an ASD. Arterial switch procedure