The electrocardiogram in atrial septal defect: A study of twenty-four cases, with observations on the RSR'-V1 pattern

Abstract

1. 1. In twenty-four patients with uncomplicated atrial septal defects, we have examined the electrocardiographic findings and their relation to the location and size of the defect, the degree of pulmonary hypertension and the ratio of pulmonic to systemic blood flow. The anatomic diagnosis was confirmed at autopsy in seven cases and at operation in seventeen cases. The septal defect was defined as persistent ostium primum in six cases and persistent ostium secundum in eighteen cases. 2. 2. Electrocardiographic evidence of right ventricular hypertrophy was present in twenty-two cases. Right axis deviation appeared in eighteen cases. 3. 3. Three patients had a persistent ostium primum, a cleft mitral leaflet and left as well as right ventricular hypertrophy, presumably due to mitral insufficiency. The electrocardiograms in these cases showed left axis deviation, with signs of both left and right ventricular hypertrophy. 4. 4. One patient, aged fifty-two years, with a persistent ostium primum, normal mitral valve and autopsy evidence of coronary insufficiency due to atherosclerosis, showed left axis deviation and complete right bundle branch block. 5. 5. An RSR'-V1 pattern was present in fifteen patients (63 per cent), two of whom had a QRS duration prolonged beyond 0.12 second. This confirms previous reports that this pattern occurs much more often with atrial septal defects than with other clinically similar lesions. The relatively high incidence of this pattern with any lesion which leads to right ventricular hypertrophy, however, and the lack of clear evidence as to its etiology suggest that it might be well to abandon the term “incomplete right bundle branch block” for the present. 6. 6. Prolongation of the PR interval was present in four of six patients with persistent ostium primum, and two of eighteen patients with persistent ostium secundum.