Normal position of great arteries

  • Aorta is posterior and right of pulmonary artery

Types of Transposition / malposition

  • dTGA with intact ventricular septum
  • lTGA
  • dTGA with VSD
  • Double outlet right ventricle with pulmonary stenosis
  • Double outlet right ventricle without pulmonary stenosis
  • Double outlet right ventricle with malposition of great arteries (Taussig Bing anomaly)

d-TGA with intact ventricular septum

  • aorta is anterior and right of pulmonary artery

Clinical manifestations

  • cyanosis and tachypnea within ==1st hour of life==
  • hypoxia depends on the ducts and level of arterial shunting
  • parasternal heave may be present
  • soft systolic ejection murmur can be noted at the mid-left sternal border

Diagnosis

X-Ray

  • Egg on string appearance
  • normal to increased pulmonary flow (increases as PVR drops)

Saturation

  • doesn't reach more than 90% even after patient breaths 100% oxygen (hypoxia test)

Echo

  • confirms the translocation of arteries
  • ducts and degree of mixing can also be accessed
  • origin of coronary artery can also be accessed

Cardiac catheterization

  • when non-invasive testing is inconclusive
  • better tool for the location of coronary artery
  • can also be used as a measure to create a temporary ==emergency balloon arterial septostomy== (RASHKIND Procedure)
  • systemic pressure = right atrial pressure

Treatment

Immediate

  • Infusion of prostaglandin E1 (0.01-0.20 mcg/kg/min) - watch for risk of apnea
  • if PgE1 fails - RASHKIND procedure

Treatment of choice

  • ==Jantane procedure== - within 2 weeks of birth
    • coronary arteries is reimplanted in neoaorta
    • avoid suture to the coronary artery
  • 2 stages arterial switch procedure - if presented late
    • 1st stage - pulmonary banding
    • 2nd stage - arterial switch

Older procedures / Arterial switch operations

  • Mustard or senning operation
    • blood from right atrium is diverted towards left atrium by means of a intraatrial baffle
  • complications
    • atrial conduction disturbances
    • sick sinus syndrome
    • atrial flutter
    • sudden death
    • superior and inferior vena cava syndromes
    • edema
    • ascites
    • protein losing enteropathy
  • right atrium remains as a pumping chamber - can lead to failure in teenage

d-TGA with VSD

d-TGA with small VSD

behaves similar to d-TGA with intact ventricular wall

d-TGA with large VSD

Clinical features

  • subtle cyanosis
  • cardiac failure
  • large heart

X-ray

  • narrow mediastinal width
  • increased pulmonary vascularity

ECG

  • prominent p wave
  • right ventricular hypertrophy / biventricular hypertrophy
  • right axis deviation

Echocardiography

  • reveals TGA
  • degree of mixing can also be identified

Cardiac catheterization

  • equal pressures in both ventricles, aorta and pulmonary artery

Management

  • surgery soon after diagnosis
  • Heart failure, if develops is difficult to manage.
  • Pre-operative management with diuretics can lessen sympoms of heart failure and stablize the patient

Surgery

  • If no pulmonary stenosis - arterial switch with VSD Closure
  • VSD maintains equal pressure in both ventricles and prevent LV mass regression, so results are equally good even if surgery is done in later periods

l-TGA / Ventricular inversion

  • right atrium is connected to right ventricle which has mitral valve and smooth vessel morphological features of left ventricle
  • left atrium is connected to left ventricle which has tricuspid valve and trabeculated normal features of a right ventricle
  • Thus the physiology of circulation is correct
  • also aorta is to the anterior (or side by side) and left of pulmonary artery

Clinical features

  • If pulmonary outflow is obstructed - similar to isolated VSD
  • if pulmonary outflow is stenosed - similar to TOF

Diagnosis

Chest X-ray

  • abnormal position of arteries
  • ascending aorta occupies upper left border of ascending aorta

ECG

  • abnormal p waves
  • absent Q waves in v6
  • abnormal Q waves in III, aVR, aVF and V1
  • upright t waves across pericardium

Echo

  • right ventricle (moderator band, coarse trabaculations, tricuspid valve) sits inferiorly compared to the mitral valve

Management

  • surgical correction of VSD (can be complicated by the bundle of His)
  • Simple surgical correction may leave the right ventricle as the systemic pumping chamber and can lead to failure
  • so recently ==Double switch operations== have be done where outflow from right atrium is diverted to structural right ventricle and left atrium to structural left ventricle and then performing a arterial switch procedure

Double outlet right ventricle

Without pulmonary stenosis

  • both aorta and pulmonary artery arise from right ventricle
  • only outlet from left ventricle is the VSD
  • similar to large VSD with left to right shunt

Diagnosis

ECG

  • biventricular hypertrophy

Echo

  • right ventricular origin of both the great arteries
  • also show the location of great arteries in relation to VSD

Management

  • depends on the location of great arteries in relation to VSD
    • VSD is subaortic
      • intracardiac tunnel is created
    • VSD is subpulmonic
      • arterial switch needed to be performed in addition to the intracardica tunnel
  • Pulmonary arterial banding may be needed in infancy to prevent heart failure and correction can be done in older years

With pulmonary stenosis

  • similar to that of TOF
  • cyanosis will be marked

Double outlet right ventricle with malposition of great arteries (Taussig Bing Anomaly)

Types

  • VSD is usually subpulmonic and aorta away from left ventricle (most common)
  • both arteries close to VSD - doubly comitted
  • neither arteries close to VSD - doubly uncomitted

Associations

  • aortic obstructive lesion are common
    • coarctation of aorta
    • valvular and subvalvular aortic stenosis
    • interruption of aortic arch

Clinical features

  • pulmonary blood flow is unobstructed
    • can cause heart failure in infancy
  • aortic obstruction
    • can cause poor systemic flow
  • cardiomegaly
  • parasternal systolic ejection murmur - sometimes preceded by ejection click and loud clousre of pulmonary valve

ECG

  • right axis deviation

X-ray

  • cardiomegaly
  • pulmonary plethora

Management

  • pulmonary banding at infancy and surgical correction at later stages accompanied by arterial switch procedure combained with intracardiac baffle (or some modification of rastelli procedure)