DuShane, James W.

Data on hemodynamic findings in 19 infants and children with ventricular septal defect are presented. The ages of these patients ranged from 3 months to 14 years. Significant elevation of pulmonary arterial pressure was found in 17 of the 19 patients studied. Left-to-right shunts, at times of large magnitude, were found in all these patients. However, right-to-left shunts accounting for up to 50 per cent of systemic flow were also obtained, even in young patients. A history suggestive of cardiac failure was obtained in seven patients. Cyanosis was constant in one patient and was found intermittently in three others. A systolic murmur was heard in most cases in the third or fourth intercostal space. In four additional patients a diastolic murmur was also identified. The electrocardiogram provided valuable information, which correlated with the relationship of pulmonary and systemic arterial resistances, the status of intracardiac shunting of blood, and the total pulmonary blood flow. These factors are considered to be of paramount importance in selection of patients for the operative closure of ventricular septal defect. It has been demonstrated that the hemodynamic status of the patient may be difficult to assess at the time of cardiac catheterization because of the unpredictable effect of anesthesia on ventilation. The use of dye-dilution curves in the diagnosis and evaluation of both right-to-left and left-to-right shunts is a vital factor in the adequate assessment of the patients from the hemodynamic standpoint.

Thirty-three cases of corrected transposition of the great vessels are analyzed: 31 of corrected transposition in situs solitus, and two of corrected transposition in situs inversus. In 18 of these 33 cases, of which 64% were males, diagnosis was confirmed by necropsy or operation. There was no history of congenital heart disease in the families of any of these patients. The person whose sole anomaly is corrected transposition has no hemodynamic basis for symptoms. Symptoms are the result of associated lesions, the most common of which are anomalies of the left atrioventricular valve usually causing incompetence, ventricular septal defects, pulmonary valvular stenosis, and advanced disturbances of atrioventricular conduction. Physical findings in corrected transposition depend upon these associated defects. Noncardiac associated anomalies are rare. Anteroposterior thoracic roentgenograms may suggest the diagnosis, particularly when a narrow waist is present at the base of the heart, accompanied by the absence of a pulmonary-artery "knob" and the presence of an enlarged left atrium. Electrocardiographic features that should suggest corrected transposition are atrioventricular block (particularly 2:1 or complete heart block), abnormal P waves, absent or low R voltage in aVR, an initial Q wave in leads 3, aVR, aVF and V1, absence of a Q wave in lead V6, upright T waves across the precordium in children, and a clockwise spatial loop in the frontal plane. Cardiac catheterization may be diagnostic in this malformation when careful documentation is made of the location of the atrioventricular valves and their relation to the semilunar valves, together with the position of the great vessels in the anteroposterior and lateral views. Alteration of hemodynamics is secondary to associated malformations. Inability to enter the pulmonary artery during catheterization should arouse suspicion, and in these cases, particularly, angiocardiography can be diagnostic. The decision as to whether the most frequently associated malformations exist as isolated entities, or whether they are present in combination with corrected transposition, appears to be the main differential problem–together with the differentiation of corrected transposition with associated cyanosis from complete (that is, uncorrected) transposition. Surgical treatment of corrected transposition has been difficult because of complete atrioventricular block before or after operation, residual incompetence when deformed left atrioventricular valves were present, and the mirror-image arrangement for the coronary arteries. The most common cause of death was cardiac failure, often with a terminal bout of pulmonary edema. The average age at death in this series was about 14 years, with a median age at death of about 4 years. A review of the literature again emphasizes the association of corrected transposition with some degree of atrioventricular block evidenced on the electrocardiogram. The most frequently reported associated cardiac lesions were ventricular septal defect, pulmonary stenosis or atresia, patent ductus arteriosus, and dextrocardia. The incidence of anomalies of the left atrioventricular valve in these reported cases has probably been underestimated.

Serial histologic sections of the atrioventricular (A-V) conduction system were studied in four hearts with persistent common A-V canal, and the anatomic findings were related to the abnormal ECG patterns. Two hearts were examples of the partial form and two of the complete form of A-V canal. The major anatomic abnormalities were: (1) postero-inferior displacement of the A-V node; (2) relatively short distances between the A-V node and the origin of the left bundle branching; (3) marked posteroinferior displacement of the left bundle branching system; and (4) relative hypoplasia of the anterior (superior) left bundle branches. The anatomic configuration of the A-V conduction system in A-V canal could result in relatively early impulse propagation to the posterior aspect of the ventricular septum as suggested by reported electrophysiologica studies. The anatomic findings are considered to be related closely to the known ECG patterns of A-V canal.

The morphology of the atrioventricular (A-V) conduction system was studied by serial histologic section in two cases of tricuspid atresia type IB (without transposition of the great arteries, with subpulmonary stenosis). The A-V node was adjacent to the central fibrous body, and its location was indicated by a "dimple" in the floor of the right atrium. The left bundle branches originated unusually close to the nodal-bundle junction. The right bundle branch was markedly elongated in its course to the right septal endocardium. It was situated along the inferior aspect of the channel-like ventricular septal defect as it traversed the septum. The early origin of the left bundle branches and the markedly elongated course of the right bundle branch were such that, theoretically, abnormal spread of the activation wave might result.

The status of 58 patients, 3 to 57 years of age, with ventricular septal defect and a marked increase in pulmonary vascular resistance (pulmonary obstructive disease) was determined 5 years or longer after diagnostic catheterization. Forty-six (80%) were alive 5 years after that study. The probability of living 5 years was 95% for patients aged 10 through 19 years and 56% for those 20 years of age or older. The dissimilarity of actuarial curves between these two groups is consistent with the hypothesis that pulmonary vascular obstructive disease develops under age 20. Calculated pulmonary resistance increased with age of patient on admission to the study, suggesting its progressive nature. Hemoptysis was rare under age 20, and its presence over this age indicated a poor prognosis. The most common causes of death were "sudden" or "unknown." Most surviving patients were gainfully employed or attending school without severe symptoms.

The atrioventricular conduction system was studied by a technique of selected serial histological sections in examples of tetralogy of Fallot and ventricular septal defect to correlate the anatomic findings observed with the electrophysiological findings as manifested by the vectorcardiographic pattern. Eight hearts were studied; two examples of each anomaly had electrocardiographic and VCG patterns in the frontal plane similar to A-V canal defects and two examples of each had ECG and VCG patterns usually associated with these lesions. Of the four examples of tetralogy, the two examples with VCG patterns similar to the A-V canal pattern differed from the other examples in that the distance between the A-V node and the origin of left bundle branching was shorter and the fibers destined to become the right bundle branch took an elongated course. The VSD examples offered less striking differences. A short distance from the A-V node to the onset of left bundle branching was seen in both examples with VCG patterns similar to the A-V canal pattern, but one example of VSD with a representative VCG pattern had a similar anatomic configuration. When measurement ratios were compared, the right bundle took its origin at a relatively greater distance from the A-V node in the examples with VCG patterns similar to the A-V canal pattern. The anatomic configuration of those examples of tetralogy and VSD with VCG patterns similar to the A-V canal pattern was such that relatively early conduction to the left bundle branch system could occur.

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.

The analysis and description of the preoperative and postoperative vectorcardiograms in tetralogy of Fallot are presented. The spatial orientation of the maximum QRS vectors to the right, anteriorly, and inferiorly in group I is indicative of right ventricular hypertrophy. In group II patients, the vectorcardiogram showed evidence of increased electrical activity of the left ventricle. Vectorcardiographic patterns of complete right bundle-branch block were noted in nine patients in group III.

A quantitative analysis was made of the pulmonary arterial medial thickness and index of medial surface area (ratio of medial tissue to pulmonary parenchyma) in 50 cases of uncomplicated ventricular septal defect in fetuses, infants, and children. The ages of the subjects ranged from 26 weeks of fetal life to 12 years. The results were compared with those obtained from a control group of the same age. During the fetal and newborn period, both the thickness and the index of surface area of the media were generally within normal limits, although in an occasional case pulmonary arterial branches were considerably thinner than those in corresponding controls. The subjects between 1 week and 5 weeks of age had a medial thickness and an index of medial surface area that were lower than the average values at the time of birth. In this regard the pulmonary arterial tree in cases of ventricular septal defect corresponded with that in normal newborn infants. Soon after, however, and most clearly from 8 weeks on, the subjects with ventricular septal defect showed a pronounced rise both in medial thickness and in the index of medial surface area, indicating the presence of considerable medial hypertrophy. Although intimal proliferation was observed in two infants of 11 and 27 days of age, it was uncommon in children less than the age of 1 year. Above that age it was almost invariably present. Plexiform or glomeruluslike structures were found in seven cases. The youngest patient with these lesions was 2½ years of age.