H. J. C. Swan

Dye Dilution Curves in Cyanotic Congenital Heart Disease

Use of cuvette and earpiece oximeters facilitates the recording of the immediate dilution pattern of the dye T-1824 (Evans blue) in the arterial blood. In patients with venoarterial shunts the pattern of the dilution curves differs from normal. Quantitative analysis of such curves from patients with cyanotic congenital heart disease has been undertaken to establish the proportion of blood which bypassed the pulmonary circulation. The results obtained have been compared with estimates of the volume of the shunt from cardiac catheterization data and related to the arterial oxygen saturation.

Demonstration of Differential Effects on Pulmonary and Systemic Arterial Pressure by Variation in Oxygen Content of Inspired Air in Patients with Patent Ductus Arteriosus and Pulmonary Hypertension

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.

Atrial Septal Defect: Factors Affecting the Surgical Mortality Rate

Analysis of accumulated experience with the repair of atrial septal defect in 119 adults has revealed several factors determinable preoperatively that appear to have a strong influence on the operative risk. These factors are related to the presence of pulmonary vascular disease or heart failure and contribute importantly to the selection of patients for operation.

Anomalous Connection of Right Pulmonary Veins to Superior Vena Cava with Interatrial Communications Hemodynamic Data in Eight Cases

Anomalous connection of the right pulmonary veins to the superior vena cava associated with an interatrial communication in an unusually cephalad location has been diagnosed at cardiac catheterization in 8 patients. These patients had the clinical features seen in patients who have atrial septal defects in the region of the fossa ovalis. Differentiation was accomplished by (1) the roentgenographic position of the catheter in the right superior pulmonary vein, (2) demonstration of an abnormally high oxygen saturation of the blood in the superior vena cava, (3) the presence of a small right-to-left shunt from the superior vena cava and the absence of such a shunt from the inferior vena cava, and (4) demonstration of similar drainage of blood from the right superior pulmonary vein and superior vena cava. The syndrome is considered to be an anomaly of pulmonary venous development while the atrial septum forms normally.

Effect of Oxygen on Pulmonary Vascular Resistance in Patients with Pulmonary Hypertension Associated with Atrial Septal Defect

The present studies are concerned with the effect of high oxygen inhalation on patients with atrial septal defects. The problem of the amount of pulmonary vascular resistance and the relative contribution of irreversible structural changes and vascular tone may be of important prognostic significance in evaluation of such patients for cardiac surgery.

Pulmonary Vascular Resistance after Repair of Atrial Septal Defects in Patients with Pulmonary Hypertension

THE BEHAVIOR of the pulmionary vascular bed in congenital heart disease is a topic of major current initerest.1 3 The control of normal pulmoiary vessels remainis a matter for debate, in part because of difficulty in measurements and in the interpretation of the smnall differences in pressure across the normal pulmoniary vascular bed. Inl the presence of pulmioniary hypertenision, however, the responses of the pulmoniary vessels nmay be assessed with greater eertainty, since sizable pressure gradients frequenitly exist. Although a pulmonary arterial systolic pressure in excess of 30 iimm. Hg is outside the norinal range in this laboratory, the categorization of all patients with septal defects and pressures above this level as havinig pulmonary hypertension is of questionable value. Accordingly, we have adopted a pullnonlarv arterial systolic pressure of 60 mm. Hg as the most suitable compromise above which patients may be said to have significant pulmonary hypertension. Such a division serves to separate most patients with congenital heart disease in whom increased pulmonary arterial pressure contributes significantly to the totai problem from those in whom it does not. Classificationi on the basis of pulinonary vaseular resistance reimains the most important conceptual differentiation but suffers from the use of values that are indirect and open to far greater error than is the simple measurement of pulmonary arterial pressure. In atrial septal defects associated with pulmonary hypertension as just defined, the pulmonary vascular resistanee usually is in-

Volume of the left ventricle in tetralogy of Fallot.

Abstract Left ventricular volumes were measured by the angiocardiographic technic in 25 patients with tetralogy of Fallot, of whom 6 had a Potts or Blalock-Taussig anastomotic operation and 5 had complete repair of the defect. In 12 of the 14 patients who underwent no surgical procedure, the left ventricular volume was in the low normal range; the 2 others (with severe forms of tetralogy of Fallot) had significantly reduced end-diastolic volumes. In patients who had an anastomotic operation, the ventricular volumes were considerably increased if the left to right flow was large enough to cause symptoms; in the others they were in the normal range. Approximately two weeks after complete repair, the mean left ventricular volume was less than that for patients not operated upon. Significant aorticopulmonary collateral flow and some flow directly from the right to the left ventricle contribute to the normal volumes of the left ventricle in tetralogy of Fallot. Left ventricular myocardial function (as evidenced by ejection fraction) is significantly better after complete repair than it is in patients not operated upon or in patients treated by an anastomotic operation.

Quantitative Estimation by Indicator-Dilution Technics of the Contribution of Blood from Each Lung to the Left-to-Right Shunt in Atrial Septal Defect

A method based on the initial portion of indicator-dilution curves has been used to determine the proportion of blood from each lung which drains anomalously. The results obtained appear to substantiate the derivation and permit the expression, in numerical values, of the greater proportion of anomalous drainage of blood from the right lung in the usual case of atrial septal defect. The principal assumptions pertaining to the method are discussed in some detail.

Transposition of the Great Vessels with Atrial Septal Defect A Hemodynamic Study in Two Cases

In complete transposition of the great vessels, survival is possible only when a route of access exists by means of which venous blood may enter the lungs. This report concerns 2 patients in relatively good health in whom a high degree of mixing of venous and arterial blood occurred through an atrial septal defect. The diagnosis was established in both patients by cardiac catheterization.