Ritter, Donald G.

Six years have passed since the first successful surgical correction of truncus arteriosus. A review of our experience enables some conclusions regarding the operation. Patients with mild or moderate truncal valve incompetence do not need truncal valve replacement. Patients with severe truncal valve incompetence require valve replacement, which is associated with a significantly increased surgical mortality. The surgical mortality is not increased in hemodynamically favorable patients who have only one pulmonary artery. However, these patients are especially likely to have early development of severe pulmonary vascular disease. The surgical mortality for the patient with uncomplicated disease and two pulmonary arteries, with pulmonary resistance of less than 8.0 units m 2 , is 10%. In patients with pulmonary resistance between 8.0 and 12 units m 2 , the mortality is approximately three times greater. Patients with pulmonary resistances greater than 12.0 units m 2 are probably inoperable. Different hemodynamic criteria must be applied in assessing the operability of patients with a single pulmonary artery. A systemic arterial oxygen saturation less than 85% in a patient with two pulmonary arteries and without pulmonary artery stenosis or a pulmonary artery band usually indicates inoperability. Elective operation usually is deferred until a patient is four years old, but if the patient's clinical condition warrants, the procedure can be done at any time after the age of one year, with a good chance of success. Follow-up on most operated patients has been encouraging.

The echocardiographic features of Ebstein's anomaly include a large anterior chamber, paradoxic ventricular septal motion (type B), increased velocity and amplitude of anterior tricuspid leaflet (ATL) motion, and delayed closure of the ATL. This delayed closure has been thought to be secondary to right bundle-branch block (RBBB). We have studied two patients by simultaneous echocardiography and phonocardiography. The findings in both patients were similar. One patient had RBBB and therefore resembles the previously reported patients. However, the other patient had W-P-W preexcitation syndrome, type B, and is reported here in more detail. The ATL closure of this patient was markedly delayed in spite of right ventricular preexcitation. This finding gives further insight into the altered pathophysiology in Ebstein's anomaly and implies that the delayed ATL closure is probably not due to RBBB and may be a specific feature of this anomaly.

During cardiac catheterization in nine patients with ventricular septal defect and seven patients with truncus arteriosus, all with severe pulmonary vascular obstructive disease, hemodynamics were compared while they were breathing first room air and then 100% oxygen. Patients with higher pulmonary vascular resistance had higher systemic vascular resistances. With 100% oxygen, pulmonary vascular resistance decreased and systemic vascular resistance increased in both groups. The effect of oxygen was found to be more pronounced on the systemic than on the pulmonary vascular bed in the patients studied. Indicator-dilution dye curves changed and exhibited characteristics of left-to-right shunts in patients with severe pulmonary vascular obstructive disease, as a result solely of an increase in systemic resistance; that is, without a decrease in pulmonary resistance. It is suggested that in patients with severe pulmonary vascular obstructive disease maintenance of an increased systemic resistance is essential to well being and is a factor in longevity. It is also suggested that any transient decrease in systemic resistance in these patients might initiate a vicious cycle leading to sudden death.

Five patients have had the common features of pulmonary atresia or severe stenosis associated with a septal defect and a coronary artery-to-pulmonary artery (CA-PA) fistula. Four had pulmonary valvular atresia, and one had severe pulmonary stenosis. In all five, the CA-PA fistula contributed the principal component of the pulmonary blood flow. Cyanosis, continuous murmur, right ventricular hypertrophy, and decreased or normal pulmonary vascularity were frequent clinical manifestations, but angiocardiography was required to establish the diagnosis. The fistula was a side-to-side communication between the left coronary artery and the main pulmonary artery in each of the five patients. The dilated proximal coronary artery connecting the aortic root with the pulmonary artery gave a unique angiocardiographic appearance distinguishing it from truncus arteriosus or aorticopulmonary window. It is suggested that this unique angiocardiographic appearance be called an "aorticopulmonary tunnel." The surgical repair of this anomaly is closely related to that for severe tetralogy of Fallot and should involve a comparable risk and achieve a comparable result.

Records of 273 cases of ventricular septal defect from five participating institutions were studied. Insignificant hemodynamic disturbance (Roger's) was found in 11 per cent, moderate to large left-to-right shunts in 55 per cent, and severe pulmonary vascular disease ("Eisenmenger's") in 8 per cent. Because of insufficient data, 26 per cent of the cases were not classified hemodynamically. Thus, a spectrum of severity ranging from mild to severe was noted. There was evidence of congestive heart failure in infancy in 78 cases and a significant mortality occurred in this group, whether treatment was medical (mortality, 27 per cent) or surgical (mortality, 46 per cent). Six patients had hemodynamic evidence of severe progressive pulmonary vascular disease, three when they were less than 8 years old. Correlations of hemodynamic severity with clinical symptoms, roentgenographic findings, and electrocardiographic changes were reasonably good at the extreme ends of the severity spectrum but only fair in the middle range. Over-all mortality was high (28 per cent) for the 163 patients treated surgically, but mortality was also high (18 per cent) for the 110 patients treated medically. Ten of the 20 deaths in the medical group occurred in patients who had had congestive heart failure in infancy. Further study of the natural history of ventricular septal defect is clearly indicated for establishment of improved criteria for selection of cases for operation.

Scalar electrocardiograms of 31 patients with double-outlet right ventricle (19 with and 12 without pulmonary stenosis) were correlated with the hemodynamic and anatomic findings. Atrioventricular conduction defects, intraventricular conduction delay, and counterclockwise frontal-plane loops were found less often than formerly reported. Counterclockwise frontal-plane loops were found with, as well as without, pulmonary stenosis. The presence or absence of left ventricular hypertrophy did not correlate with the severity of pulmonary vascular obstructive disease. Electrocardiographic evidence of left atrial enlargement was difficult to interpret. Additional intracardiac malformations could not be appreciated from the electrocardiographic findings. The predictive value of the electrocardiogram for the diagnosis of double-outlet right ventricle was considered to be low. In patients with double-outlet right ventricle without pulmonary stenosis, the electrocardiogram was not helpful in predicting the severity of pulmonary vascular obstructive disease.

Echocardiograms were performed on 20 children who were 1-14 years old. Ten children had secundum atrial septal defects (ASD 2°); four had partial and two had complete atrioventricular canal defects (AVC); and three had partial and one had total anomalous pulmonary venous connection (APVC). Twenty-eight normal children were also examined. Echocardiograms of nine patients with ASD 2° revealed increased right ventricular dimension index (RVDI) and abnormal (paradoxic) ventricular septal (VS) motion. The remaining patient with ASD 2°, who had a Qp/Qs of 1.2 (smallest in the series), had a normal echocardiogram. All four patients with APVC had increased RVDI, and three had abnormal VS motion. The patient with normal septal motion had associated mild aortic stenosis, but he too had a small left-to-right shunt (19%). The echocardiograms of two patients with partial AVC revealed features similar to ASD 2°, but in the third patient who had significant mitral regurgitation (MR) the VS motion was normal, indicating that the degree of associated MR influences the VS motion in this anomaly. The septal motion was normal in both patients with complete AVC. Three patients in the series had abnormal systolic anterior motion of mitral valve. Postoperative echocardiograms revealed persistence of increased RVDI and "paradoxic" VS motion.