Congenital heart disease

Abstract

Dr. Frederick K. Heath: Congenital heart disease includes a wide variety of anatomic defects, about one-half of which produce significant physiologic abnormalities. This half, representing about 1 per cent of all organic heart disease and about 2 per cent of that seen in children, recently has become the center of great physiologic and surgical interest. For advances in vascular surgery have made it possible to achieve dramatic and often life-saving results in this group of patients. Coincidently, investigation by means of the intravenous catheter had progressed so far that precise diagnostic and postoperative follow-up information could be obtained. This was important since it soon became obvious that clinical appraisal based only on physical findings and statistics gave neither accurate diagnosis nor quantitative information regarding cardiac function. Important, too, is the use of radiographic technics whereby the abnormality may be visualized. The four cases presented serve to illustrate present day technics and their limitations, how data obtained by catheterization technics are interpreted, and representative results of surgical therapy. They also emphasize the frequent occurrence of multiple defects. By means of cardiac catheterization with simultaneous measurement of the blood oxygen content and pressures in the various chambers it is possible by application of the Fick principle to calculate cardiac output, to define the systemic and pulmonary circulation in terms of volume flow per unit of time, and to estimate, when present, the direction of shunt flow. In connection with pressure measurements it is to be remembered that an increase in pressure may result from obstruction to flow, e.g., stenosis of the pulmonary artery, in which case the rate of flow will be decreased; or on the other hand, it may simply be due to an increased rate of flow per se. It is clear that information both as to pressure and rate of flow are important for interpretation. Accurate anatomic and physiologic estimations are of invaluable aid in deciding whether or not operative interference should be helpful. Thus in simple patent ductus arteriosus an excellent result is to be expected. Of twenty-six uncomplicated cases of this condition operated upon by Dr. Humphreys only one death occurred postoperatively and only one proven recurrence was noted. When the patent ductus arteriosus is complicated by other defects, the outlook depends upon the nature of these complications. In this group the operative mortality and results are decidedly less favorable. When indicated, i.e., cyanotic heart disease, the creation of an artificial ductus, as carried out by Dr. Blalock, may relieve cyanosis but it also increases the pulmonary blood flow and the work of the heart. Whether eventual cardiac hypertrophy and failure, pulmonary congestion and polycythemia may be postoperative sequelae is not yet clear. These findings were observed in one patient thought to have a tetrad of Fallot plus a patent ductus arteriosus from birth; yet in patients receiving an artificial ductus the disappearance of polycythemia has been encountered.