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What are the investigation findings in ASD (atrial septal defect) ?

The main diagnostic modalities of ASD are ECG, chest X-ray and echocardiogram.
The findings are listed below.
ECG findings in ASD
  • There is right axis deviation in ECG. Axis may be deviated to left in ostium primum defet.
  • Right bundle branch block (RBBB)
RBBB is due to delayed activation of the posterobasal part of ventricular septum and due to enlarged ventricular outflow tract.
Chest X-ray findings in ASD
Chest X-ray will show
  • Enlarged right atria and right ventricle
  • Prominence of main pulmonary artery
  • Pulmonary plethora
Chest X-ray also help to differentiate between mitral stenosis and ASD. Left atrial enlargement is the striking features of MS which is absent in ASD.
Echocardiograpy in ASD
Echocardiography shows  the definitive features of ASD
  • Right ventricular dilatation
  • Paradoxical septal motion
Subcostal echo is best in visualising the defect
2D- echo with Doppler is the confirmatory diagnostic test
Transesophageal echo: Useful in ambiguous transthoracic  Echo.
Cardiac catheterisatiom in ASD is done in case of
  • Coronary artery disease
  • Valvular heart disease
  • Pulmonary artery hypertension.

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