Burchell, Howard B.

Obstruction to pulmonary blood flow may occur in the pulmonic valve, in the infundibulum or in both. Cardiac catheterization aids in the determination of the site of obstruction. Criteria for the differentiation at operation of valvular and infundibular pulmonic stenosis are enumerated, and the usefulness of accurate pressure tracings during operation is emphasized. The accurate identification of the site or sites of obstruction to pulmonary blood flow is essential to proper surgical management. A correctly selected operation must be carried out in as complete a manner as possible.

Seven cases of patent ductus arteriosus with pulmonary hypertension and reversal of the usual direction of flow are described. Breathing of a low oxygen mixture either initiated or increased the reversed shunt, and breathing 100 per cent oxygen produced the reverse effect. Differences in oxygen saturation and dye-dilution curves recorded simultaneously from the radial and femoral arteries have allowed calculation of differences in the proportion of shunted blood flowing in these arteries and demonstrate that retrograde movement of blood in the aortic arch may occur.

This study was undertaken to ascertain whether coarctation of the aorta produces permanent hemodynamic abnormalities that may persist despite resection and end-to-end anastomosis. The results of studies in 10 patients 4 to 7 years after operation are compared to those obtained before and immediately after operation. The most significant finding was continued decrease in residual coarctation, in addition to dramatic immediate postoperative improvement in the degree of circulatory impairment.

In a necropsy study of 50 cases of ventricular septal defects, the anatomic position and relations of ventricular septal defects, the causes of and ages at death, and association of ventricular septal defects with other cardiovascular malformations were determined. The present availability of surgical closure of ventricular septal defects makes this information of practical significance.

Arterial dilution curves of T-1824 have been recorded by oximeters after injection of T-1824 into both the right and left pulmonary arteries in patients with anomalous connections of the pulmonary veins, with atrial septal defects or with persistent common atrioventricular canals. The most extreme differences were found between the pairs of curves in the patients with the anomalous connection. These differences were less pronounced but clearly recognizable in the other conditions, and suggested a more general use of the term "anomalous pulmonary venous drainage. "The findings indicate that, in the usual case of atrial septal defect, a greater proportion of the blood from the right lung passes to the right atrium than does blood from the left lung.

The combination of patent ductus arteriosus and coarctation of the aorta poses special anatomic, physiologic and surgical problems. An experience with 14 such cases is presented, which suggests that pulmonary hypertension occurs frequently in these cases. Physiologic data in cases having coarctation of the aorta, patent ductus arteriosus and pulmonary hypertension that underwent cardiac catheterization are presented. Clinical, anatomic, physiologic and surgical implications of this combination are discussed.

An experience with surgical treatment for atrial septal defects in 59 patients has given evidence as to the safety and efficacy of the procedure utilizing the atrial-well technic. Data from the first 33 cases of this series are presented in detail, to allow analysis by others of the basis for these conclusions.

Previous studies in this series demonstrated structural changes in the pulmonary vascular bed as the result of mitral valvular disease and other cardiac disorders. The present study demonstrates changes in the lungs as the result of chronic left ventricular failure; these changes were like those produced by mitral stenosis. The most pronounced disturbance was medial hypertrophy. The exact mechanism is not known, but it probably is related to increased pulmonary venous pressure.