James R. Zuberbuhler

Prevalence of congenital cardiac anomalies at high altitude

The effect of high altitude on the prevalence of congenital heart disease was tested by examining 1,116 school children at four study sites in the Peoples Republic of China. Sites ranged in altitude from sea level to 4,500 m above sea level. Children were screened by physical examination, and an echocardiogram and electrocardiogram were performed on each child suspected of having a cardiac anomaly. A high prevalence of patent ductus arteriosus and atrial septal defect was found at the three high altitude sites and the effect of altitude was progressive. Both anomalies were postulated to be the result of the lower atmospheric oxygen tension present at high altitude. Failure of lower oxygen tension to constrict the ductus is thought to be the mechanism in patent ductus arteriosus. It is theorized that the persistence of high pulmonary vascular resistance and high right heart pressures at high altitude inhibits early closure of the foramen ovale. Subsequent growth may result in stretching of the fossa ovalis and incompetence of the flap and may produce an atrial septal defect. The high prevalence of atrial septal defect in tetralogy of Fallot is cited as a possible analogy because right ventricular pressure is high and right ventricular compliance is low from birth.

Congenitally unguarded tricuspid orifice: its differentiation from Ebstein's malformation in association with pulmonary atresia and intact ventricular septum.

SummaryDysplasia of the leaflets is a well-known integral part of Ebsteins malformation. It is less well-recognized that occasionally the septal leaflet may be completely absent and not simply displaced from its usual annular attachment. This may make it difficult to differentiate by echocardiography between Ebsteins malformation and the rare lesion in which the tricuspid orifice is completely devoid of leaflet tissue (“congenitally unguarded orifice”). A neonatal case is described in which a partially unguarded orifice was present in association with pulmonary atresia and intact ventricular septum but misdiagnosed as Ebsteins malformation. In addition we reviewed the morphologic features of all 46 cases of pulmonary atresia and intact septum in the Cardiopathological Collection of the Childrens Hospital of Pittsburgh: 17 also had Ebsteins malformation, while three had a congenitally unguarded tricuspid orifice.We found that the differential diagnosis occurred when the right ventricle was dilated rather than being a hypoplastic cavity, as was a feature of all the cases with unguarded orifice and five of those with Ebsteins malformation. The difference between the lesions is best demonstrated by examining the mural leaflet of the valve, which is absent when the orifice is unguarded but displaced in association with Ebsteins malformation. This feature should be recognizable by cross-sectional echocardiography. We have confirmed previous studies that dilatation of the chambers of the right heart indicates a very poor prognosis in cases with pulmonary atresia and an intact ventricular septum.

Ventricular septal defect associated with aneurysm of the membranous septum

The most common variety of ventricular septal defect, a perimembranous defect, is frequently associated with a so-called aneurysm of the membranous septum. Previous studies have suggested that ventricular septal defects associated with an aneurysm of the membranous septum tend to spontaneously decrease in size or close more than defects without such an aneurysm. To better define the natural history of this entity, clinical and catheterization data from 87 patients with ventricular septal defect and aneurysm of the membranous septum were reviewed. The initial evaluation was made at a median age of 0.3 years (range 0.1 to 11), with the final evaluation at a median age of 10 years (range 1.5 to 20) and a median duration of follow-up of 8.6 years (range 1.2 to 18.8). Approximately 75% of the ventricular septal defects had a small or no left to right shunt at last evaluation. Overall, 48 patients (55%) had no significant change in the size of the defect, and 39 (45%) showed improvement during the period of observation. Only four patients (5%) had spontaneous closure of the defect. Of the 49 patients who presented with a large left to right shunt, with or without congestive heart failure, 23 (47%) had persistence of a shunt large enough to warrant surgery. When spontaneous improvement occurred, it did so by 6 years of age in all but one patient. Therefore, a continued tendency for a ventricular septal defect associated with an aneurysm of the membranous septum to spontaneously decrease in size or close after this age may be less likely than previously suggested.(ABSTRACT TRUNCATED AT 250 WORDS)

Successful dilatation of a stenotic Blalock-Taussig anastomosis by percutaneous transluminal balloon angioplasty.

Abstract In recent years, the technique of percutaneous transluminal balloon angioplasty has been applied to patients with congenital heart disease. Lesions that have been successfully treated by this technique include pulmonary valvular stenosis, 1,2 aortic valvular stenosis, 3 coarctation of the aorta 4,5 and restenosis of coarctation of the aorta after previous surgical repair. 6 We describe the successful use of this procedure in dilating a severely stenotic Blalock-Taussig (B-T) systemic-to-pulmonary artery (PA) anastomosis in a patient whose complex cyanotic heart malformation was not amenable to surgical correction.

Identification and analysis of left atrial isomerism

The veno-atrial connections, atrial morphology, atrioventricular (AV) junction, ventricular mass, ventriculoarterial (VA) connection and great arteries in 22 autopsied hearts, diagnosed as having bilateral left-sidedness because of the morphology of the atrial appendages, were studied. The findings were correlated with the arrangement of the thoracic-abdominal organs. A solitary spleen was found in 3 and double spleens in 2 hearts (the remaining 17 hearts had multiple spleens) but left bronchial isomerism existed in all hearts in which bronchial arrangement could be determined. The heart was in the left chest in 14 cases, in the right chest in 5 and midline in 3. The apex pointed to the left in 18 hearts while in 4 hearts it pointed to the right. Fifteen hearts had a biventricular and ambiguous AV connection, 3 hearts had an absent left AV connection and 4 had double-inlet connection via a common valve (to the left ventricle in 3 and the right ventricle in 1). The VA connection was concordant in 14 hearts, discordant in 1, double outlet from the right ventricle in 4, double outlet from a solitary indeterminate ventricle in 1 and single outlet from the right ventricle through a pulmonary trunk with aortic atresia in 2 hearts. Superior caval veins were present bilaterally in 13 hearts. There was interruption of the infrahepatic inferior caval vein with azygos or hemiazygos continuation in 19 hearts while in 3 hearts the inferior caval vein continued upwards to drain into the right-sided morphologically left atrium.(ABSTRACT TRUNCATED AT 250 WORDS)

Effectiveness of the Rashkind Procedure in Transposition of the Great Arteries in Infants

The immediate and long-term efficacy of the balloon atrial septostomy (BAS) was appraised in a series of 43 patients with transposition of the great arteries. Early effectiveness was gauged by changes in oxygen saturation and atrial pressures, and by balloon catheter measurement of the interatrial opening immediately following BAS. BAS was initially effective in 31 cases. In 20 patients the size of the interatrial opening was measured by balloon catheter from three months to three years after initially successful BAS. In 13 of these the opening was less than 12 mm; 7 subsequently required surgical septectomy, and each of the remaining 6 had a ventricular septal defect. In the other 7, the opening was greater than 12 mm; none have required surgical septectomy. A total of 13 patients required late septectomy, with only one death. In contrast, there was a 40% (17/44) surgical mortality with surgical septectomy in a similar group of patients between 1959 and 1966. It is concluded that balloon atrial septostomy is initially effective and relatively safe, but that, particularly in those with intact ventricular septum, surgical septectomy is often required. Balloon catheter measurement of the interatrial opening has been helpful in predicting the necessity for surgical septectomy.

Echocardiographic-morphologic correlations in tricuspid atresia

OBJECTIVES Our aim was to clarify the anatomic substrate in hearts diagnosed as having tricuspid atresia by studying autopsy specimens and comparing the findings with those in two-dimensional echocardiograms. BACKGROUND Traditionally, tricuspid atresia was thought, and is still believed by some, to be due to an imperforate valvular membrane interposed between the floor of the blind-ending right atrium and the hypoplastic right ventricle. Others argued that the dimple, when present, pointed to the outflow tract of the left ventricle rather than to the right ventricle, making the lesion more akin to double-inlet left ventricle. METHODS We examined 39 autopsy specimens catalogued as having tricuspid atresia. We then studied 24 two-dimensional echocardiograms from patients with a primary diagnosis of tricuspid atresia. RESULTS Of the 39 specimens, 37 had a completely muscular floor to the right atrium (absent right atrioventricular [AV] connection). The dimple, when identified, was (except in one case) directed to the left ventricular outflow tract. Only two hearts had an imperforate tricuspid valve. Two-dimensional echocardiograms in all cases showed an echo-dense band, produced by the fibrofatty tissue of the AV groove and representing absence of the right AV connection, between the muscular floor of the morphologically right atrium and the ventricular mass. CONCLUSIONS Tricuspid atresia is usually, but not always, due to morphologic absence of one AV connection. In most cases, the ventricular mass then comprises a dominant left ventricle together with a rudimentary and incomplete right ventricle.

Himalayan P-Waves in a Patient With Tricuspid Atresia

An 8-month-old female infant was diagnosed with tricuspid atresia in utero by an ultrasound and the diagnosis was confirmed at birth. She underwent a modified Blalock-Tausig shunt at the age of 2 months to treat increasing cyanosis. She did well and is waiting to complete single ventricle palliation. On her recent follow-up, she was asymptomatic, with a …

Balloon pulmonary valvuloplasty in a child with Ebstein's anomaly and valvar pulmonary stenosis

We performed a balloon pulmonary valvuloplasty in a child with Ebsteins anomaly using the standard technique. The procedure reportedly has not been performed in the face of this defect and, although difficult, was safely and successfully accomplished. In patients with Ebsteins anomaly and right ventricular outflow obstruction compounded by pulmonary valve stenosis, application of this technique may delay the need for surgical intervention.

Surgical Significance of Morphological Variations in the Atrial Septum in Atrioventricular Septal Defect for Determination of the Site of Penetration of the Atrioventricular Conduction Axis

The morphological variation in the recognized landmarks for the atrioventricular conduction system was studied grossly in 94 hearts with atrioventricular septal defect, assessing 20 hearts with normal atrioventricular septation as a control. In all the hearts with intact atrioventricular septal structures, the tendon of Todaro demarcated the superior boundary of the triangle of Koch. In hearts with atrioventricular septal defect, however, the landmarks for the conduction axis made up a separate nodal triangle. The tendon of Todaro, along with a bridging tendon not found in the normal heart, were variably developed in hearts with atrioventricular septal defect and formed a further triangle unrelated to the axis for atrioventricular conduction. The opening of the coronary sinus was also variable in its location and size. It was the location of the inferior bridging leaflet as it crossed the ventricular septum that was the best surgical landmark to the site of penetration of the atrioventricular conduction axis.