The role of coronary artery abnormalities in the prognosis of truncus arteriosus.

A high incidence of coronary ostial and arterial abnormalities was found in a study of 30 pathologic specimens of classic truncus arteriosus at Children's Hospital of Pittsburgh. The following were of special note: (1) left coronary ostium in a posterior and high position; (2) close relation of the left coronary ostium to the pulmonary artery segment in three-leaflet truncal valves; (3) stenosis of the coronary ostium caused by small size, slitlike shape, or the location of the ostium above or in a commissure; (4) the acute angle takeoff of the coronary artery; (5) the position of the left anterior descending artery as it courses posteriorly and close to the truncal wall, and then to the left of the interventricular septum; (6) the size and course of the conal and diagonal arteries from the right coronary artery across the right ventricular outflow area; (7) other coronary abnormalities, including a single coronary artery or ostium with branches crossing the right ventricle below the truncus, the circumflex arising from the right coronary artery and coursing behind the truncus, and the right coronary artery originating from the left anterior descending artery and vice versa. Eight heart specimens with conduit repair were reviewed, and all had injury to coronary arteries, possibly responsible for or contributing to the deaths of six of the eight patients. Coronary abnormalities, often several occurring in combination, may contribute to high operative mortality rate and may be a cause of late sudden death in truncus arteriosus. Surgical procedures should be planned with a view to protecting coronary arteries in the region of the right ventricular outflow tract below the truncus. Coronary artery obstruction (ostial or luminal) can occur and may need to be addressed as a separate issue during surgical procedures.

Conduction tissue anomalies in absence of the right superior caval vein.

The incidence of electrical instability of the heart is high in patients with absence of the right and persistence of the left superior caval vein when the latter connects to the coronary sinus. It has been suggested that a large coronary sinus may influence the susceptibility to arrhythmias. we studied the conduction tissues of 8 hearts from the cardiopathological collection of Children's Hospital of Pittsburgh. Six of these specimens had a persistent left superior caval vein connecting to the coronary sinus. There were 4 with absence of the right superior caval vein, 3 of which were in the group with persistent left veins. We evaluated the sinus node and the specialized atrioventricular junctional area, comparing them with known normals. The coronary sinus varied in size from through it. The size did not alter the histology of the adjacent conduction tissue. In contrast, the sinus node was abnormal in 3 of the 4 hearts with absent right superior caval vein. This may be the key factor in the development of arrhythmias when the right superior caval vein is absent or abnormal.

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)

Tetralogy of Fallot with absent pulmonic valve: analysis of 17 patients.

Seventeen patients with tetralogy of Fallot (TF) and absent pulmonic valve were seen at Children's Hospital of Pittsburgh from 1958 to 1981. In 7 patients, severe respiratory symptoms developed due to bronchial compression by an aneurysmal pulmonary artery, and 6 died. In 4 patients, moderate respiratory symptoms developed. Six patients remained free of respiratory distress. Medical and surgical management of patients with respiratory distress in infancy has been frustrating and frequently unsuccessful. A 4-month-old infant with respiratory distress underwent complete intracardiac repair with valve insertion and has subsequently survived with relief of symptoms. Considering the high mortality rate in this group of patients, further attempts at aggressive surgical repair in infancy for patients with severe respiratory symptoms is warranted. An anatomic review of pathologic specimens with this anomaly confirmed previous reports of the frequent association of absence of the ductus arteriosus in patients with tetralogy of Fallot and absent pulmonary valve. The exception is noted in patients with discontinuity between the right and left pulmonary arteries in which a ductus arteriosus may be present supplying the isolated left pulmonary artery.

The morphology of ventricular septal defects.

Ventricular septal defect (VSD) is the most common congenital cardiac lesion, occurring either in isolation or in hearts containing more complex lesions. Usually, the defect is between two ventricles, each of which is connected to a separate atrium and to a separate great artery, and surgical or spontaneous closure of the VSD basically corrects the circulation if the effects of any associated lesion are ignored. In other situations, the VSD is an integral part of the circulation, either because the atria connect to only one ventricle or because the ventricles give rise to only one patent great artery or else both great arteries arise from the same ventricle. When in such circumstances the circulation is VSD-dependent and the defect cannot be surgically closed without bypassing it with a conduit or similar device. In all of these situations, the VSD takes one of three basic forms. Usually, the VSD abuts directly upon the fibrous skeleton of the heart formed by the conjoined rings of the cardiac valves. The membranous part of the ventricular septum is an integral part of this skeleton, and these defects are termed perimembranous. These defects do not always occupy the same part of the septum. They may extend mostly into either the inlet, trabecular, or outlet parts of the muscular septum, or else be confluent extending into two or all these parts. Less commonly, VSD may be exclusively contained within the muscular septum. Such muscular defects can also be confined to either the inlet, trabecular, or outlet parts of the septum. They may be multiple or coexist with one of the other types. The third and least common type is a VSD which is roofed by the conjoined rings of the aortic and pulmonary valves because of absence of the outer septum. Such a defect may have a muscular posteroinferior rim or may extend to become perimembranous. Identifying a defect as perimembranous or muscular, together with its location relative to the different parts of the muscular septum, gives at the same time information concerning the site of the conduction axis in relation to the defect and its chances of spontaneous closure.

Double-inlet left ventricle with rudimentary right ventricle and ventriculoarterial concordance.

Seven hearts were studied that had in common the segmental combination of double-inlet left ventricle, rudimetary right ventricle and ventriculoarterial concordance. The prototype of these hearts has been described as the "Holmes heart" or "single ventricle type A1." Five of the hearts had 2 atrio-ventricular valves; in 1 of these the right valve was minimally straddling. The other 2 had a common valve. In 6 of the hearts the rudimentary right ventricle was obliquely situated on the anterior surface of the dominant left ventricle. The trabecular component was anterior and right-sided with the outlet components and pulmonary trunk in left-sided position. In the final case, both trabecular and outlet components of the rudimentary right ventricle were left-sided. Conduction tissue studies were performed in 2 hearts. In 1, the connecting atrioventricular node and bundle were in anomalous anterolateral position, as expected in double-inlet left ventricle. In the other, a ring-like, posterior, nonbranching bundle connected the regular node in the atrial septum to the branching bundle positioned on the anterior interventricular septum. The anatomic findings are related to the likely modes of presentation and differential diagnosis while the conduction tissue findings are discussed in the light of options for surgical repair. Thus, the term "single ventricle" is best avoided when describing hearts that unequivocally possess 2 ventricular chambers.

Mechanisms of closure of perimembranous ventricular septal defect.

Although more defects in the muscular ventricular septum close spontaneously than do defects abutting on the membranous septum (perimembranous defects), a good proportion of the latter show a tendency to diminish in size and to close. The mechanism responsible for this closure is usually described as an aneurysm of the membranous septum, although some doubt has been cast as to whether this is the precise mechanism. In this study, 69 unoperated hearts with ventricular septal defect were examined; 26 (38%) showed some evidence of partial closure and none extended exclusively into the outlet part of the septum. Two thirds of the trabecular perimembranous defects, almost half of the inlet defects, and one third of the confluent defects showed signs of partial occlusion. The anatomic structures most frequently responsible were reduplication of tricuspid valve tissue (16 cases), adhesion of tricuspid valve leaflets (6 cases), and prolapse of an aortic valve leaflet (3 cases). Only in 2 cases were subaortic tissue tags observed which might have originated from the remnant of the membranous septum. The present study shows that although anatomic evidence of partial closure was present in two fifths of the hearts studied, only rarely was it due to so-called aneurysm of the membranous septum.

Morphology of ventricular septal defect associated with coarctation of aorta.

It is now well established that the morphology of the ventricular septal defect associated with interrupted aortic arch is such as to compromise blood flow to the ascending aorta. Though there is some evidence that a similar mechanism may be operative in coarctation with ventricular septal defect, we are unaware of any necropsy study of this hypothesis. We therefore studied 25 hearts from the Heart Museum of Children's Hospital of Pittsburgh with coarctation and ventricular septal defect. Four had a malalignment defect with left ventricular outflow tract obstruction such as is seen in cases with interruption. Twenty of the remaining cases had a particular form of perimembranous defect with aortic overriding. The defects were partially closed by tricuspid valve tissue, the left ventricular outflow tract being further narrowed by various anatomical lesions. In addition, mitral valve malformations were present in 14 cases. The anatomy of the group as a whole suggests a possible reduction of aortic blood flow during fetal development. The clinical implications of these findings remain to be evaluated.

The anatomical heterogeneity of hearts lacking a patent communication between the left atrium and the ventricular mass ('mitral atresia') in presence of a patent aortic valve.

Thirty-five hearts were studied with no patent communication between the left atrium and the ventricular mass ('mitral atresia'). In ten, an imperforate and hypoplastic membrane separated the left atrium from a hypoplastic left ventricle. The imperforate valve ranged from a tiny membrane with no evidence of tension apparatus, through a larger membrane supported by muscular columns in the ventricular inlet portion, to an aneurysmal imperforate sac attached to a single hypoplastic papillary muscle. The ventriculo-arterial connection was concordant in nine of the ten hearts and double outlet from the right ventricle in one. In one further heart, there was double inlet left ventricle with imperforate left atrioventricular valve, a rudimentary right ventricle and ventriculo-arterial discordance. In the other 24 hearts the muscular floor of the left atrium was completely separated by the atrioventricular sulcus from the ventricular mass (absent left atrioventricular connection). In 11 of these hearts, the right atrium was connected to a right ventricle and there was a posterior and left-sided rudimentary left ventricular chamber which had no connection with the atrial chambers. The left ventricle supported the aorta in five of the 11 hearts, but in the other six it was simply a pouch of left ventricular morphology. In ten cases the right atrium was connected to a dominant left ventricle. An anterior rudimentary right ventricle was present in each but had no connection with the atrial chambers. It was to the left of the left ventricle in seven, directly anterior in one and to the right in two cases. The right ventricle supported the aorta in eight cases, the pulmonary trunk in one and neither great artery in the remaining case. Lastly, there were three cases in which a sole ventricular chamber of indeterminate morphology was present and gave rise to both great arteries.

Hemodynamic function after the Mustard operation for transposition of the great arteries.

Pre- and postoperative cardiac catheterization data and cinenangiocardiograms of 82 patients who survived the Mustard operation for transposition of the great arteries (TGA) were reviewed. The post-operative catheterizations were performed 20 days to 10 years after operation (mean 2.5 years). Forty-six patients (56%) had no or insignificant associated cardiac lesions, whereas 36 (44%) had ventricular septal defect, pulmonary stenosis, or both, and required surgical intervention at the time of the Mustard operation. Postoperatively, 11 patients (13%) had significant systemic venous obstruction. Of the 11 patients, 6 required reoperation, and 2 patients had evidence of restenosis or complete obstruction in the superior vena cava after reoperation. In most patients, superior vena caval obstruction was well tolerated even in the presence of high pressure in the superior vena cava. Pulmonary venous obstruction occurred in 5 patients (6%), 3 of whom had no clinical symptoms despite severe pulmonary venous obstruction, although all had radiographic evidence of pulmonary venous congestion. The incidence of obstruction was drastically reduced after the Mustard operation was modified to include routine enlargement of the pulmonary venous atrium. Tricuspid regurgitation was uncommon (10%), but did occur in patients who had transatrial closure of a ventricular septal defect. Preoperatively, left ventricular outflow obstruction occurred in 38%. In 12 patients an attempt was made to relieve the obstruction at surgery. The 6 patients who had localized obstruction had a good result, but patients with more diffuse narrowing of left ventricular outflow had little or no relief of obstruction. Mild to moderate left ventricular outflow gradients regressed spontaneously in most patients after the Mustard operation.

Exercise studies after the Mustard operation in transposition of the great arteries.

Twenty-one postoperative patients with transposition of the great arteries (TGA) underwent graded exercise testing 4 to 15 years (mean 9) after the Mustard operation. No patient had subjective exercise intolerance before testing, although some had symptomatic resting arrhythmias. Correlations were made between cardiac catheterization data and 24-hour ambulatory monitoring. Exercise tolerance was diminished in nearly half of the patients. No statistically significant differences were found in heart rate or blood pressure responses, but maximal oxygen consumption values were lower than the control values (p less than 0.001) in the larger patients. Arrhythmias were present or provoked in most patients during exercise testing. Only 28% remained in normal sinus rhythm during and after exercise. Multifocal premature contractions were the most serious arrhythmias demonstrated. Some long-term survivors of the Mustard operation may have abnormal exercise dynamics, even though they may be asymptomatic and have normal physical activities and endurance. Mean maximal systolic blood pressure, heart rate, oxygen consumption, and maximal treadmill times were consistently in the low-normal range or were statistically lower than normal.

Arrhythmias in transposition of the great arteries after the Mustard operation.

Disorders of rhythm or conduction in patients with transposition of the great arteries (TGA) after the Mustard operation have been widely reported. This study provides a systematic evaluation of the electrophysiologic function of 87 survivors of the Mustard operation at a single institution. Surface electrocardiograms were reviewed in all 87 patients, Holter monitoring data in 26 patients, exercise electrocardiograms in 21 patients, and invasive electrophysiologic data in 61 patients. Surface electrocardiograms showed normal sinus rhythm in 52%, sinus node dysfunction in 27%, and atrioventricular block in 16%. Holter monitoring was obtained in an unselected subgroup of 26 patients who had a mean age of 12 years and a mean interval from operation of 9 years. Sinus node dysfunction was found in 58%, atrioventricular block in 27% ventricular ectopy in 50%, supraventricular ectopy in 27%, and no abnormalities in only 8%. Intracardiac electrophysiologic evaluation showed a high frequency of abnormal sinus node recovery times and suboptimal response of the atrioventricular-conduction system to rapid atrial pacing. When all modalities used in this study were considered, sinus node dysfunction occurred in 47%, ectopy in 34% and atrioventricular block in 23%. Although only 30% of patients had no evidence of arrhythmia, symptoms of rhythm or conduction disturbances were rare.

Blade atrial septostomy: collaborative study.

During the past 4 years, five institutions have collaborated in evaluating the efficacy of blade atrial septostomy. The procedure was performed in 52 patients, including 31 with transposition of the great arteries, 10 with mitral atresia, five with tricuspid atresia and six with miscellaneous anomalies. The patient's ages ranged from 1 day to 12 years (mean 13 months). Improvement occurred in 41 of 52 patients (79%). Four patients had an intact interatrial septum, and blade atrial septostomy was successfully performed by a transseptal technique. One patient died from a lacerated left atrial wall; other complications occurred in four patients. Blade atrial septostomy is an effective palliative procedure, even when the interatrial septum is thickened or intact.

Surgical anatomy of tetralogy of Fallot.

On the basis of previous experience, we have analyzed the anatomy of a series of 53 hearts catalogued as having tetralogy of Fallot in the museum of the Children's Hospital of Pittsburgh. All hearts had a ventricular septal defect, aortic overriding, infundibular pulmonary obstruction, and right ventricular hypertrophy. None of the hearts had been operated upon during life. We paid particular attention to features of surgical importance. Thus the ventricular septal defect was found to be of variable form. It was perimembranous in 42 hearts. In 11 hearts it had entirely muscular rims and in the remaining heart it was roofed by the conjoined aortic and pulmonary valve rings (subarterial). From our previous histologic experience, it was evident that this varying morphology significantly affected the surgical anatomy of the atrioventricular conduction tissues. We endeavored to display this disposition as might be viewed by the surgeon. The degree of aortic override was variable, the aortic valve being connected by 15% to 95% to the right ventricle. In 17 hearts more than half the aortic valve was attached to right ventricular musculature. The nature of the infundibular obstruction also varied markedly. In all cases (except the one with absent infundibular septum) the infundibular septum was deviated in cephalad and anterior direction so as to produce obstruction. In the majority of hearts further anatomic structures also contributed to the obstruction. In some hearts there was hypertrophy of the infundibular septum, particularly at its junction with the trabecular septum. In others there was hypertrophy of the trabecula septomarginalis, and in many hearts there was hypertrophy of additional anterior infundibular trabeculations. The pulmonary valve was the narrowest point of the outflow tract in only six hearts, but in many of the others, it was abnormal. The results emphasize that while hearts may exhibit the classical features of tetralogy of Fallot, there is usually considerable individual variation in each of these features which is of major surgical significance.

Electrocardiogram in double chamber right ventricle.

Thirty patients with a double chamber right ventricle were seen during a 7 year period. The majority of patients had associated cardiac anomalies, most commonly a ventricular septal defect. In this series, as in others, the history, clinical examination, chest roentgenogram and echocardiogram were inconclusive for diagnosing double chamber right ventricle. Symptoms were generally related to the severity of the associated anomalies. In 40 percent of the patients reviewed, upright T waves were found in lead V3R as the only electrocardiographic finding suggestive of right ventricular hypertrophy. Because upright T waves in lead V3R in the absence of other evidence of right ventricular hypertrophy are not commonly seen in patients with an isolated ventricular septal defect or a defect associated with other forms of right ventricular outflow obstruction, this finding should alert the cardiologist to the possibility of the presence of double chamber right ventricle prior to cardiac catheterization.

Absent right superior vena cava with persistent left superior vena cava: implications and management.

Seven cases of absent right superior vena cava with persistent left superior vena cava and normal situs were diagnosed at Children's Hospital of Pittsburgh. All patients had associated cardiac defects. In two cases the diagnosis was made at autopsy, the first in 1957 and in a 26 day old infant with multiple cogenital defects and the second in 1965 in a 22 day old infant who had pulmonary atresia with ventricular septal defect and patent ductus arteriosus. Since 1966 absent right superior vena cava has been diagnosed at cardiac catheterization in five children. Three of these children have had surgery, two for subaortic stenosis and one for an atrial septal defect. One has an insignificant atrial septal defect and the fifth has a ventricular septal defect. The electrocardiogram of four reveals s short P-R interval and a leftward frontal plane axis of the P wave, suggesting a low atrial focus. None has had any significant conduction problem. All five children are living and well, the oldest has survived 13 years postoperatively. Certain precautions are necessary should corrective cardiac surgery or transvenous pacemaker insertion be necessary.