IS Case 105: Previously unsuspected Atrial Septal Defect

Veniamin Barshay, MD

Imaging Sciences URMC
Publication Date: 2009-05-20


A 51-year-old male presented with dyspnea. Chest CT angiogram demonstrated no pulmonary embolus (PE). However, due to high clinical suspicion for PE, pulmonary angiogram was requested.


The pigtail catheter was advanced from the IVC to the right atrium and manipulated to cross the tricuspid valve. However, catheter position was more superior than expected position of the right ventricle (Fig. 1). Contrast injection confirmed catheter position in the pulmonary vein and left atrium (Fig. 2) due to the unsuspected atrial septal defect. No pulmonary embolus was found on the pulmonary angiogram after the catheter was repositioned.


Previously unsuspected Atrial Septal Defect


Atrial septal defect is the most common cardiac anomaly in adults. Most common type, ostium secundum, involves fossa ovalis. The other types include:

  1. sinus venosus, located high in the atrial septum near the entry of the SVC and associated with anomalous connections of right pulmonary veins to the SVC and right atrium, and
  2. ostium primum, located near the atrioventricular valves, which may be malformed, and associated with Down's syndrome and other chromosomal anomalies.

Anatomical closure of foramen ovale normally follows functional closure soon after birth. Incomplete closure with "probe patency" is asymptomatic and considered a normal variant. Functional patency with left to right shunt can become symptomatic and require surgical closure. Complications include pulmonary hypertension, paradoxic pulmonary embolism in the setting of atrial fibrillation, and congestive heart failure.


  1. Fauci AS, Braunwald E, Isselbacher KJ, et al. (eds). Harrison's Principles of Internal Medicine, 14th ed; McGraw-Hill, 1999:1303-4.

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