Differentiation of Interatrial Communications by Clinical Methods

Of 128 children with anatomically confirmed interatrial communications 74 had ostium secundum, 37 had ostium primum defects, 5 had common atrium, and 12 had total anomalous pulmonary venous connection. Analysis of the medical history, physical examination, roentgenogram, and electrocardiogram resulted in accurate diagnosis in most instances. In 6 of the 128 patients the proper diagnosis was not made: 3 infants with total anomalous pulmonary venous connection died within a few hours after admission to the hospital and did not have proper diagnostic evaluation; the condition of 3 other patients with ostium secundum defects was misdiagnosed as ostium primum defect before surgical treatment. In patients with ostium secundum and ostium primum defects the symptoms, signs, roentgenologic data, and findings at cardiac catheterization are similar, but differences in respect to the electrocardiograms are striking when the latter are subjected to vectorial analysis. The QRS loop is clockwise in the presence of ostium secundum defect and counterclockwise when ostium primum defect is at hand. Clinical and roentgenologic manifestations also are noted among patients with common atrium and total anomalous pulmonary venous connection, and the findings at cardiac catheterization likewise may be similar, but the electrocardiographic differences are significant. The QRS loop is counterclockwise in patients with common atrium and clockwise in patients with total anomalous pulmonary venous connection.