John D. Keith

THE ANOMALOUS ORIGIN OF THE LEFT CORONARY ARTERY FROM THE PULMONARY ARTERY

Considerable variation in origin and distribution of the coronary arteries has been described over the years. One of the most interesting anomalies is that of the left coronary artery arising from the pulmonary artery in a heart without other defects, first described by Abrikosoff in 1911. Cases were reported sporadically in the next twenty years but clinical interest was not aroused until Bland, White, and Garland, in 1933, integrated the clinical and pathological data and recorded an electrocardiogram in an infant dying of this condition. In all, nearly 50 cases have been reported, and the author has had an opportunity of studying 10 more at the Hospital for Sick Children in recent years. Bland et al. reported finding this aberrant left coronary once in 6800 necropsies at the Massachusetts General Hospital over a period of thirty-seven years. In the total group of congenital heart disease we have found this anomaly to occur in 0 5 per cent of cases. In relating it to child population in the Toronto Heart Registry it appears once in 300,000 children. It is undoubtedly a rare defect but its diagnosis during life is now possible in most cases, and successful surgery appears within reach. Most instances of this defect have been found in babies who have died in the first year of life. However, survival into adult life is possible, and this appears to occur in approximately 15 per cent of cases. Kaunitz, in 1947, presented data on 7 such cases: the oldest was sixty-four and was first reported by Abbott in 1927. All of the adults were discovered, incidentally, at autopsy, and usually in subjects who had died suddenly without obvious clinical cause. Pathology. At necropsy the origin of the left coronary artery is not immediately visible and attention is attracted first to the grossly enlarged left ventricle of aneurysmal proportions, with a ventricular wall that appears somewhat thin in proportion to its size. In most studies the left ventricular wall is actually normal in thickness and only occasionally is it either obviously hypertrophied or pathologically thin. However, as might be expected, the right ventricle by comparison is small and compressed. The total heart weight is increased (see Fig. 1). Patchy fibrosis is found in the left ventricle, particularly at the apex, and over the anterior portion of the myocardium (Fig. 2). It involves all layers down to the endocardium, and the latter shows a diffuse endocardial fibroelastosis. The fibrosis of the muscle of the left ventricle diminishes in degree as one approaches the collateral branches of the right coronary on either side. Histologically the muscle fibres are increased in number and may present a patchy disintegration. There is an increase in elastic tissue in the involved areas and often some cedema. In the more advanced cases calcification within the myocardium has been noted: Kaunitz (1947) reported this finding in slightly over half the cases.

Anatomic types of congenital dextrocardia: Diagnostic and embryologic implications☆☆☆

Abstract The anatomic findings in 51 necropsied cases of congenital dextrocardia are presented. The diagnostic and embryologic implications of these findings are assessed. A new general anatomic classification is proposed which is equally applicable to right-sided and to left-sided hearts, either with two well-developed ventricles or with single (common) ventricle. The proposed classification, which is specifically designed to facilitate accurate diagnosis of the relative locations of the cardiac chambers by current investigative methods, is based upon two considerations: (1) the type of viscero-atrial situs present, and (2) the type of cardiac loop which coexists. The type of visceral situs, established radiologically, always is the same as the atrial situs. Thus, the visceral situs indicates the atrial locations with virtually complete accuracy. The type of relationship between the great arteries at the semilunar valves, determined angiocardiographically, indicates the type of cardiac loop present and, hence, the relative location of each ventricle. Thus, the great arteries identify the ventricles with great accuracy. Three types of relationship are considered, an appreciation of which greatly simplifies and clarifies ones understanding of congenital heart disease: (1) viscero-atrial; (2) bulboventricular (great arteries to ventricles); and (3) bulboventriculovisceral (types of cardiac loop relative to types of viscero-atrial situs). The malformation which recently has been regarded as “classic dextroversion” very probably is nonexistent. The incidence of the tetralogy of Fallot in dextrocardia has been greatly overestimated, probably because of confusion with transposition, pulmonary stenosis and ventricular septal defect. The mirror-imagery of inversion is considered to be a biologic illusion. Rudimentary spleen (polysplenia) appeared to be a forme fruste of asplenia. Posterior transposed aorta is described.

Clinical,angiocardiographic, and pathologic findings in 100 patients

Salient clinical, hemodynamic, angiocardiographic, and pathologic findings are presented in 100 patients with truncus arteriosus communis, 79 of whom were studied at autopsy. In this study of typical truncus, all had a ventricular septal defect (type A). Truncus with a partially formed aorticopulmonary septum (type A1) was much the commonest form (50%). Cases with no remnant of aorticopulmonary septum (type A2) were second in frequency (21%). The distinction between types A1 and A2 could not be made with certainty in 9%, because these types merge into one another. Cases with absence of either pulmonary artery branch (type A3) were the least frequent form (8%). Truncus with interruption, atresia, preductal coarctation, or severe hypoplasia of the aortic arch (type A4) constituted 12%. The diagnosis of truncus is primarily angiocardiographic. The plane of the truncal valve in the lateral projection is distinctive. It tilts anteriorly, facing the patients toes, which can be of assistance in differential diagnosis. The angiocardiographic features of type A4, although unfamiliar, are pathognomonic. Since the median age at death was only 5 weeks, and in view of the difficulties associated with pulmonary artery banding, our goal should be the surgical correction of truncus during the first and second months of life.

Ventricular septal defect with increased pulmonary vascular resistance: Late results of surgical closure

Abstract The fate of 57 children who underwent surgical closure of ventricular septal defect in the presence of increased pulmonary vascular resistance was analyzed. Eighteen (32 percent) died at or immediately after operation. Seven late deaths, due to the Eisenmenger syndrome, occurred 1 to 7 years after operation. Follow-up studies, including cardiac catheterization, were performed in 25 survivors, 1 to 11 years (mean 5 years) after operation. In patients operated on after age 2 years, the degree of preoperative elevation of pulmonary vascular resistance largely determined the prognosis: The condition of patients with mild elevation (pulmonary vascular resistance less than one third the systemic level) returned to normal after operation, with one exception. Patients with more severe elevation (pulmonary vascular resistance more than one third the systemic level) most often showed progressive pulmonary vascular disease; the condition of a few remained unchanged and that of only one returned to normal after operation. Operative mortality rate was high in children with elevated pulmonary vascular resistance during the second year of life who were operated on before age 2 years, but pulmonary vascular resistance returned to normal in the three survivors. When pulmonary vascular resistance was increased in the first year of life, it generally decreased spontaneously (independently of operation); the early increase in these cases is believed to represent delayed maturation of the pulmonary vascular bed rather than pulmonary vascular disease. The overall results of surgery in ventricular septal defect associated with a high level of pulmonary vascular resistance are unfavorable and call for interruption of the natural history before significant pulmonary vascular obstructive changes have taken place; this can be achieved by surgical closure before age 2 years or pulmonary artery banding in infancy.

Spontaneous Closure of Ventricular Septal Defects

A group of 37 children is described in whom a systolic murmur heard early in life gradually diminished and eventually disappeared. When the patients were first seen, the clinical findings suggested a small ventricular septal defect but no thrill was present and the systolic murmur had a superficial blowing quality with high-frequency vibrations and tended to stop before the second heart sound. Cardiac catheterization demonstrated a small left-to-right shunt at ventricular level in 4 of the patients while the murmur was present; in 1 this was repeated after the murmur had gone and no abnormality could be demonstrated. Cardiac catheterization in other patients with typical disappearing systolic murmurs showed a left-to-right shunt in some but in others this was too small to be detected by routine oxygen studies. A rough correlation was established between the length and intensity of the murmur and the size of the shunt. With angiocardiography and intracardiac phonocardiography the exact site of the ventricular septal defect was localized to the muscular portion of the septum in 4 of the patients. In 1 patient who presented with congestive heart failure, clinical and hemodynamic findings of a large ventricular septal defect diminished over several years and finally disappeared. Children with the specific type of systolic murmur described may be recognized as having a small defect in the muscular ventricular septum. The defect is thought to be gradually reduced in size and ultimately closed by hypertrophy of septal muscle. Spontaneous closure appears to be not uncommon with small ventricular septal defects and may rarely occur with lesions large enough to present with congestive heart failure.

Incidence of Bacterial Endocarditis in Ventricular Septal Defects

In summary, the population figures presented place the risk of bacterial endocarditis for cases of ventricular septal defect in the 5 to 14-year age group as 1 in 470 patient years, or 2.1 per 100 cases in 10 years. The estimated risks for the 5-year-old and 15-year-old patient up to the age of 70 years would be 13.6% and 11.5% respectively. In the city of Toronto, only four cases were seen in 10 years in the general population of over half a million, while in metropolitan Toronto with the population of 1.3 million, eight cases were seen in a similar period. If the clinical experiences of the various authors reported in the literature are pooled with that at The Hospital for Sick Children in Toronto, one would have 21 cases of bacterial endocarditis in 11,328 patient years. This would place the incidence as approximately 1 in 500 patient years.It is suggested that the surgery for ventricular septal defect may itself initiate bacterial endocarditis as noted in three of our cases.On the basis of the available data, there is insufficient evidence to designate the risk of future bacterial endocarditis as an adequate reason for surgical closure of the defect.

Pediatric cardiologyVentricular septal defect with increased pulmonary vascular resistance: Late results of surgical closure☆

Abstract The fate of 57 children who underwent surgical closure of ventricular septal defect in the presence of increased pulmonary vascular resistance was analyzed. Eighteen (32 percent) died at or immediately after operation. Seven late deaths, due to the Eisenmenger syndrome, occurred 1 to 7 years after operation. Follow-up studies, including cardiac catheterization, were performed in 25 survivors, 1 to 11 years (mean 5 years) after operation. In patients operated on after age 2 years, the degree of preoperative elevation of pulmonary vascular resistance largely determined the prognosis: The condition of patients with mild elevation (pulmonary vascular resistance less than one third the systemic level) returned to normal after operation, with one exception. Patients with more severe elevation (pulmonary vascular resistance more than one third the systemic level) most often showed progressive pulmonary vascular disease; the condition of a few remained unchanged and that of only one returned to normal after operation. Operative mortality rate was high in children with elevated pulmonary vascular resistance during the second year of life who were operated on before age 2 years, but pulmonary vascular resistance returned to normal in the three survivors. When pulmonary vascular resistance was increased in the first year of life, it generally decreased spontaneously (independently of operation); the early increase in these cases is believed to represent delayed maturation of the pulmonary vascular bed rather than pulmonary vascular disease. The overall results of surgery in ventricular septal defect associated with a high level of pulmonary vascular resistance are unfavorable and call for interruption of the natural history before significant pulmonary vascular obstructive changes have taken place; this can be achieved by surgical closure before age 2 years or pulmonary artery banding in infancy.

Ventricular septal defect Incidence, morbidity, and mortality in various age groups

The true incidence of isolated ventricular septal defect and its subdivisions is difficult to estimate accurately, since the data available in the past have been obtained in a variety of incomplete ways. Necropsy studies usually included the complicated as well as the isolated cases. The clinical diagnostic criteria were less accurate than those used currently. Some studies dealt only with adults; other reports omitted infants or took patients into the investigation series at different ages. It is reasonable to conclude that no final figures will ever be arrived at, since the factors affecting prevalence data are changing continuously and no two studies are identical or complete. However, it is worth while considering some of the information obtained in the past from certain specific points of view.

DIAGNOSIS OF THE ANATOMIC TYPES OF SINGLE OR COMMON VENTRICLE.

Abstract The present report seeks to determine whether or not one can accurately diagnose the various anatomic types of single ventricle by clinical and laboratory methods. The history, physical examination, chest roentgenograms and electrocardiogram usually were diagnostically nonspecific. Despite its lack of specificity, the electrocardiogram in single left ventricle with an infundibular outlet chamber usually could be understood in terms of the type of bulboventricular loop which was present. Cardiac catheterization often provided the first clue to the presence of a single ventricle: a large left to right shunt at the ventricular level, despite systemic pressure in the “right” ventricle; and an extraordinarily wide range of oxygen content from different sites in the ventricle, and even from the same site. Selective ventricular angiocardiography is the diagnostic method of choice. Two groups can be distinguished: (1) single ventricle with an outlet chamber, and (2) single ventricle without an outlet chamber. Those with an outlet chamber have absence of the right ventricular sinus (inflow tract). This results in a single left ventricle with an infundibular outlet chamber, the relatively frequent type of single ventricle (79% of this series).

Double outlet right ventricle {S,D,L} with subaortic ventricular septal defect and pulmonary stenosis: Report of six cases☆

The clinical, hemodynamic, angiocardiographic and pathologic findings are presented in an infrequent but surgically correctable type of double outlet right ventricle. This study is based on six cases, one with autopsy confirmation. In all, the viscera and atria were in situs solitus (S). A ventricular d-loop was present (D). There was I-malposition of the great arteries, the aorta being to the left of, and anterior to, the pulmonary artery (L). Hence, this anomaly may conveniently be represented as double outlet right ventricle (S,D,L,). The ventricular septal defect to the ventricular septum. A bilateral conus was present beneath both the aortic and pulmonary valves, preventing any semilunar-atrioventricular fibrous continuity. The subpulmonary conus was poorly expanded, resulting in pulmonary infundibular and valvular (annular) stenosis. The clinical features were those of cyanosis, clubbing and accentuation of the second heart sound in the pulmonary area (related to aortic valve closure). There was a systolic ejection murmur along the upper left sternal border, related to pulmonary outflow tract stenosis. Selective right and left ventricular angiocardiography was diagnostic. Relatively early surgical correction is suggested to minimize the progression of pulmonary infundibular stenosis and to avoid acquired atresia. In this malformation, pulmonary outflow tract reconstruction is more difficult than in tetralogy of Fallot because of the rather posterior location of the pulmonary outflow tract, and because the right coronary artery crosses the stenotic pulmonary outflow tract in front of the pulmonary valve.